84 results on '"Rowlands DS"'
Search Results
2. An epigenetic clock for human skeletal muscle
- Author
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Voisin, S, primary, Harvey, NR, additional, Haupt, LM, additional, Griffiths, LR, additional, Ashton, KJ, additional, Coffey, VG, additional, Doering, TM, additional, Thompson, JM, additional, Benedict, C, additional, Cedernaes, J, additional, Lindholm, ME, additional, Craig, JM, additional, Rowlands, DS, additional, Sharples, AP, additional, Horvath, S, additional, and Eynon, N, additional
- Published
- 2019
- Full Text
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3. Effects of ß-hydroxy-ß-methylbutyrate supplementation during resistance training on strength, body composition, and muscle damage in trained and untrained young men: a meta-analysis.
- Author
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Rowlands DS and Thomson JS
- Abstract
Beta-hydroxy-beta-methylbutyrate (HMB) is a popular supplement in the resistance training community, with its use supported by claims of increased strength, muscle growth, and improved recovery; however, research outcomes are variable. Therefore, we meta-analyzed the effectiveness of HMB on strength, body composition, and muscle damage. Nine qualifying studies yielded 14 comparisons subcategorized by training experience (trained, untrained) to provide 12-13 estimates of strength (upper body, lower body, overall average), 13 estimates of fat and fat-free mass, and 7 estimates of the muscle-damage marker creatine kinase. The meta-analysis comprised 394 subjects (age 23 +/- 2 years, mean +/- between-study SD) with 5 +/- 2 weeks' intervention and 5 +/- 6 h.wk of training. The estimates were analyzed using a meta-analytic mixed model with study sample size as the weighting factor that included the main-effect covariates to control for between-study differences in HMB dose, intervention duration, training load, and dietary cointervention. To interpret magnitudes, meta-analyzed effects were standardized using the composite baseline between-subject SD and were qualified using modified Cohen effect size thresholds. There were small benefits to lower-body (mean +/- 90% confidence limit: 9.9% +/- 5.9%) and average strength (6.6 +/- 5.7%), but only negligible gains for upper-body strength (2.1 +/- 5.5%) were observed in untrained lifters. In trained lifters, all strength outcomes were trivial. Combined (all studies), the overall average strength increase was trivial (3.7 +/- 2.4%), although uncertainty allows for a small benefit. Effects on fat and fat-free mass were trivial, and results regarding creatine kinase were unclear. Supplementation with HMB during resistance training incurs small but clear overall and leg strength gains in previously untrained men, but effects in trained lifters are trivial. The HMB effect on body composition is inconsequential. An explanation for strength gains in previously untrained lifters requires further research. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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4. Effects of nine weeks of ß-hydroxy-ß methylbutyrate supplementation on strength and body composition in resistance trained men.
- Author
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Thomson JS, Watson PE, and Rowlands DS
- Abstract
The dietary supplement beta-hydroxy-beta-methylbutyrate (HMB) is claimed to increase strength, lean body mass, and decrease fat mass when used in conjunction with resistance training. Although there is some support for these claims, the evidence is not conclusive, and it is even less so for resistance trained individuals. Therefore, we aimed to further elucidate the effects of HMB supplementation in trained men. A randomized, double-blind, controlled study design was used to investigate the effects of supplementing 22 resistance trained men with 3 g.d of HMB or corn starch placebo for 9 weeks with resistance training. The effect of HMB on strength was determined using the 1-repetition maximum (1RM) method for the lower body (leg extension) and upper body (bench press, bicep preacher curl) at baseline and after the supplementation period. Body composition was assessed by skinfolds and bioelectrical impedance analysis (BIA). Overall, 9 weeks' HMB supplementation resulted in a clear-cut, trivial increase in combined averaged strength measures of 1.6% (90% confidence limits: +/-4.3%). When considered in isolation, however, leg extension 1RM increased by a substantial 9.1% (90% confidence limits: +/-7.5%), but the effect on upper-body strength was inconclusive (bench press: -1.9 +/- 9.3%; bicep curl: -1.7 +/- 4.7%). Based on BIA estimates, HMB had a decreasing (although inconclusive) influence on fat mass of -9 +/- 14%, but it had a clear, trivial effect on fat-free mass of 0.2 +/- 2.2%. The magnitude of change in body mass was trivial, but the probability of substantial reductions in skinfold thicknesses ranged from negligible to likely. In previously trained men, supplementation of HMB in conjunction with resistance training provides a substantial benefit to lower-body strength, but it has negligible effects on body composition. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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5. Effect of dietary protein content during recovery from high-intensity cycling on subsequent performance and markers of stress, inflammation, and muscle damage in well-trained men.
- Author
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Rowlands DS, Rössler K, Thorp RM, Graham DF, Timmons BW, Stannard SR, and Tarnopolsky MA
- Published
- 2008
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6. Oxidation of combined ingestion of maltodextrins and fructose during exercise.
- Author
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Wallis GA, Rowlands DS, Shaw C, Jentjens RLP, and Jeukendrup AE
- Abstract
PURPOSE: To determine whether combined ingestion of maltodextrin and fructose during 150 min of cycling exercise would lead to exogenous carbohydrate oxidation rates higher than 1.1 g.min. METHODS: Eight trained cyclists VO2max: 64.1 +/- 3.1 mL.kg.min) performed three exercise trials in a random order. Each trial consisted of 150 min cycling at 55% maximum power output (64.2+/-3.5% VO2max) while subjects received a solution providing either 1.8 g.min of maltodextrin (MD), 1.2 g.min of maltodextrin + 0.6 g.min of fructose (MD+F), or plain water. To quantify exogenous carbohydrate oxidation, corn-derived MD and F were used, which have a high natural abundance of C. RESULTS: Peak exogenous carbohydrate oxidation (last 30 min of exercise) rates were approximately 40% higher with combined MD+F ingestion compared with MD only ingestion (1.50+/-0.07 and 1.06+/-0.08 g.min, respectively, P<0.05). Furthermore, the average exogenous carbohydrate oxidation rate during the last 90 min of exercise was higher with combined MD+F ingestion compared with MD alone (1.38+/-0.06 and 0.96+/-0.07 g.min, respectively, P<0.05). CONCLUSIONS: The present study demonstrates that with ingestion of large amounts of maltodextrin and fructose during cycling exercise, exogenous carbohydrate oxidation can reach peak values of approximately 1.5 g.min, and this is markedly higher than oxidation rates from ingesting maltodextrin alone. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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7. The sensory acceptance of fibre-enriched cereal foods: A meta-analysis
- Author
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Grigor, JM, Brennan, CS, Hutchings, SC, and Rowlands, DS
- Published
- 2016
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8. Standardization and other approaches to meta-analyze differences in means.
- Author
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Hopkins WG and Rowlands DS
- Subjects
- Humans, Data Interpretation, Statistical, Models, Statistical, Meta-Analysis as Topic
- Abstract
Meta-analysts often use standardized mean differences (SMD) to combine mean effects from studies in which the dependent variable has been measured with different instruments or scales. In this tutorial we show how the SMD is properly calculated as the difference in means divided by a between-subject reference-group, control-group, or pooled pre-intervention SD, usually free of measurement error. When combining mean effects from controlled trials and crossovers, most meta-analysts have divided by either the pooled SD of change scores, the pooled SD of post-intervention scores, or the pooled SD of pre- and post-intervention scores, resulting in SMDs that are biased and difficult to interpret. The frequent use of such inappropriate standardizing SDs by meta-analysts in three medical journals we surveyed is due to misleading advice in peer-reviewed publications and meta-analysis packages. Even with an appropriate standardizing SD, meta-analysis of SMDs increases heterogeneity artifactually via differences in the standardizing SD between settings. Furthermore, the usual magnitude thresholds for standardized mean effects are not thresholds for clinically important differences. We therefore explain how to use other approaches to combining mean effects of disparate measures: log transformation of factor effects (response ratios) and of percent effects converted to factors; rescaling of psychometrics to percent of maximum range; and rescaling with minimum clinically important differences. In the absence of clinically important differences, we explain how standardization after meta-analysis with appropriately transformed or rescaled pre-intervention SDs can be used to assess magnitudes of a meta-analyzed mean effect in different settings., (© 2024 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.)
- Published
- 2024
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9. A very-low-calorie diet (VLCD) intervention for the management of prediabetes and early Type 2 diabetes mellitus in a multi-ethnic cohort in Aotearoa New Zealand: The PROGRESS NZ feasibility study.
- Author
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Whitfield PL, Hall RM, Théaude L, Sixtus RP, Kanaan R, Holley AS, Umpleby AM, Weatherall M, Rowlands DS, and Krebs JD
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- Humans, Male, New Zealand, Middle Aged, Cohort Studies, Adult, Aged, Body Composition, Weight Loss, Blood Glucose, Diabetes Mellitus, Type 2 diet therapy, Prediabetic State diet therapy, Prediabetic State therapy, Feasibility Studies, Caloric Restriction methods
- Abstract
Background and Objectives: Very-low calorie diets (VLCD) achieve weight loss and remission of Type 2 diabetes (T2DM), but efficacy and acceptability in non-European populations is less clear. This feasibility study examines the impact of 10% weight loss through VLCD on metabolic and body composition outcomes in a multi-ethnic cohort of Aotearoa New Zealand (AoNZ) men with prediabetes/early T2DM, and VLCD tolerability/cultural acceptability., Methods and Study Design: Participants followed a VLCD intervention (mean energy 3033kJ/day) until achievement of 10% weight loss. An oral glucose tolerance test (OGTT), hyperinsulinaemic isoglycaemic clamp with stable isotopes, hood calorimetry and dual-energy Xray absorptiometry (DXA) were undertaken before and after intervention. Qualitative data on VLCD tolerability/cultural acceptability were collected., Results: Fifteen participants were enrolled; nine achieved 10% weight loss. In this group, mean HbA1c reduced by 4.8mmol/mol (2.4-7.1) and reverted to normoglycaemia in n=5/9; mean body weight reduced by 12.0 kg (11.0-13.1) and whole-body glucose disposal improved by 1.5 mg kgFFM-1 min-1 (0.7-2.2). Blood pressure and fasting triglycerides improved significantly. No changes in hepatic glu-cose metabolism were found. In all participants who attended completion testing, HbA1c reduced by 3.4mmol/mol (SD 3.5) and total weight by 9.0kg (SD 5.7). The intervention was highly tolerable/culturally acceptable however challenges with fulfilment of cultural obligations were described., Conclusions: Results support VLCD use in AoNZ however further work to investigate ethnic differences in physiological response to VLCDs and to optimise protocols for multi-ethnic populations are required., Competing Interests: The authors have no conflicts of interest to declare
- Published
- 2024
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10. Postexercise muscle glycogen synthesis with glucose, galactose, and combined galactose-glucose ingestion.
- Author
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Podlogar T, Shad BJ, Seabright AP, Odell OJ, Lord SO, Civil R, Salgueiro RB, Shepherd EL, Lalor PF, Elhassan YS, Lai YC, Rowlands DS, and Wallis GA
- Subjects
- Female, Humans, Male, Blood Glucose, Dietary Carbohydrates pharmacology, Eating physiology, Glycogen, Insulin, Muscle, Skeletal physiology, Double-Blind Method, Galactose, Glucose
- Abstract
Ingested galactose can enhance postexercise liver glycogen repletion when combined with glucose but effects on muscle glycogen synthesis are unknown. In this double-blind randomized study participants [7 men and 2 women; V̇o
2max : 51.1 (8.7) mL·kg-1 ·min-1 ] completed three trials of exhaustive cycling exercise followed by a 4-h recovery period, during which carbohydrates were ingested at the rate of 1.2 g·kg-1 ·h-1 comprising glucose (GLU), galactose (GAL) or galactose + glucose (GAL + GLU; 1:2 ratio). The increase in vastus lateralis skeletal-muscle glycogen concentration during recovery was higher with GLU relative to GAL + GLU [contrast: +50 mmol·(kg DM)-1 ; 95%CL 10, 89; P = 0.021] and GAL [+46 mmol·(kg DM)-1 ; 95%CL 8, 84; P = 0.024] with no difference between GAL + GLU and GAL [-3 mmol·(kg DM)-1 ; 95%CL -44, 37; P = 0.843]. Plasma glucose concentration in GLU was not significantly different vs. GAL + GLU (+ 0.41 mmol·L-1 ; 95%CL 0.13, 0.94) but was significantly lower than GAL (-0.75 mmol·L-1 ; 95%CL -1.34, -0.17) and also lower in GAL vs. GAL + GLU (-1.16 mmol·-1 ; 95%CL -1.80, -0.53). Plasma insulin was higher in GLU + GAL and GLU compared with GAL but not different between GLU + GAL and GLU. Plasma galactose concentration was higher in GAL compared with GLU (3.35 mmol·L-1 ; 95%CL 3.07, 3.63) and GAL + GLU (3.22 mmol·L-1 ; 95%CL 3.54, 2.90) with no difference between GLU + GAL (0.13 mmol·L-1 ; 95%CL -0.11, 0.37) and GLU. Compared with galactose or a galactose + glucose blend, glucose feeding was more effective in postexercise muscle glycogen synthesis. Comparable muscle glycogen synthesis was observed with galactose-glucose coingestion and exclusive galactose-only ingestion. NEW & NOTEWORTHY Postexercise galactose-glucose coingestion or exclusive galactose-only ingestion resulted in a lower rate of skeletal-muscle glycogen replenishment compared with exclusive glucose-only ingestion. Comparable muscle glycogen synthesis was observed with galactose-glucose coingestion and exclusive galactose-only ingestion.- Published
- 2023
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11. Changes to insulin sensitivity in glucose clearance systems and redox following dietary supplementation with a novel cysteine-rich protein: A pilot randomized controlled trial in humans with type-2 diabetes.
- Author
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Peeters WM, Gram M, Dias GJ, Vissers MCM, Hampton MB, Dickerhof N, Bekhit AE, Black MJ, Oxbøll J, Bayer S, Dickens M, Vitzel K, Sheard PW, Danielson KM, Hodges LD, Brønd JC, Bond J, Perry BG, Stoner L, Cornwall J, and Rowlands DS
- Subjects
- Adult, Humans, Glucose metabolism, Cysteine metabolism, Pilot Projects, Insulin metabolism, Muscle, Skeletal metabolism, Protein Isoforms metabolism, Dietary Supplements, Oxidation-Reduction, Keratins metabolism, Keratins pharmacology, Insulin Resistance, Diabetes Mellitus, Type 2 metabolism
- Abstract
We recently developed a novel keratin-derived protein (KDP) rich in cysteine, glycine, and arginine, with the potential to alter tissue redox status and insulin sensitivity. The KDP was tested in 35 human adults with type-2 diabetes mellitus (T2DM) in a 14-wk randomised controlled pilot trial comprising three 2×20 g supplemental protein/day arms: KDP-whey (KDPWHE), whey (WHEY), non-protein isocaloric control (CON), with standardised exercise. Outcomes were measured morning fasted and following insulin-stimulation (80 mU/m
2 /min hyperinsulinaemic-isoglycaemic clamp). With KDPWHE supplementation there was good and very-good evidence for moderate-sized increases in insulin-stimulated glucose clearance rate (GCR; 26%; 90% confidence limits, CL 2%, 49%) and skeletal-muscle microvascular blood flow (46%; 16%, 83%), respectively, and good evidence for increased insulin-stimulated sarcoplasmic GLUT4 translocation (18%; 0%, 39%) vs CON. In contrast, WHEY did not effect GCR (-2%; -25%, 21%) and attenuated HbA1c lowering (14%; 5%, 24%) vs CON. KDPWHE effects on basal glutathione in erythrocytes and skeletal muscle were unclear, but in muscle there was very-good evidence for large increases in oxidised peroxiredoxin isoform 2 (oxiPRX2) (19%; 2.2%, 35%) and good evidence for lower GPx1 concentrations (-40%; -4.3%, -63%) vs CON; insulin stimulation, however, attenuated the basal oxiPRX2 response (4%; -16%, 24%), and increased GPx1 (39%; -5%, 101%) and SOD1 (26%; -3%, 60%) protein expression. Effects of KDPWHE on oxiPRX3 and NRF2 content, phosphorylation of capillary eNOS and insulin-signalling proteins upstream of GLUT4 translocation AktSer437 and AS160Thr642 were inconclusive, but there was good evidence for increased IRSSer312 (41%; 3%, 95%), insulin-stimulated NFκB-DNA binding (46%; 3.4%, 105%), and basal PAK-1Thr423 /2Thr402 phosphorylation (143%; 66%, 257%) vs WHEY. Our findings provide good evidence to suggest that dietary supplementation with a novel edible keratin protein in humans with T2DM may increase glucose clearance and modify skeletal-muscle tissue redox and insulin sensitivity within systems involving peroxiredoxins, antioxidant expression, and glucose uptake., Competing Interests: Declaration of competing interest We were unable to get the Elsevier online DOI working, so this document covers declarations., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2023
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12. A role for β-catenin in diet-induced skeletal muscle insulin resistance.
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Masson SWC, Dissanayake WC, Broome SC, Hedges CP, Peeters WM, Gram M, Rowlands DS, Shepherd PR, and Merry TL
- Subjects
- Mice, Animals, Proto-Oncogene Proteins c-akt metabolism, Phosphatidylinositol 3-Kinases metabolism, beta Catenin metabolism, beta Catenin pharmacology, Glucose metabolism, Muscle, Skeletal metabolism, Insulin metabolism, Diet, High-Fat, Phosphorylation, Glucose Transporter Type 4 metabolism, Insulin Resistance genetics, Diabetes Mellitus, Type 2 metabolism
- Abstract
A central characteristic of insulin resistance is the impaired ability for insulin to stimulate glucose uptake into skeletal muscle. While insulin resistance can occur distal to the canonical insulin receptor-PI3k-Akt signaling pathway, the signaling intermediates involved in the dysfunction are yet to be fully elucidated. β-catenin is an emerging distal regulator of skeletal muscle and adipocyte insulin-stimulated GLUT4 trafficking. Here, we investigate its role in skeletal muscle insulin resistance. Short-term (5-week) high-fat diet (HFD) decreased skeletal muscle β-catenin protein expression 27% (p = 0.03), and perturbed insulin-stimulated β-catenin
S552 phosphorylation 21% (p = 0.009) without affecting insulin-stimulated Akt phosphorylation relative to chow-fed controls. Under chow conditions, mice with muscle-specific β-catenin deletion had impaired insulin responsiveness, whereas under HFD, both mice exhibited similar levels of insulin resistance (interaction effect of genotype × diet p < 0.05). Treatment of L6-GLUT4-myc myocytes with palmitate lower β-catenin protein expression by 75% (p = 0.02), and attenuated insulin-stimulated β-catenin phosphorylationS552 and actin remodeling (interaction effect of insulin × palmitate p < 0.05). Finally, β-cateninS552 phosphorylation was 45% lower in muscle biopsies from men with type 2 diabetes while total β-catenin expression was unchanged. These findings suggest that β-catenin dysfunction is associated with the development of insulin resistance., (© 2023 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)- Published
- 2023
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13. Oxidation of independent and combined ingested galactose and glucose during exercise.
- Author
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Odell OJ, Impey SG, Shad BJ, Podlogar T, Salgueiro RB, Rowlands DS, and Wallis GA
- Subjects
- Male, Female, Humans, Adult, Oxygen Consumption, Blood Glucose metabolism, Dietary Carbohydrates metabolism, Oxidation-Reduction, Glucose metabolism, Galactose
- Abstract
Coingestion of glucose and galactose has been shown to enhance splanchnic extraction and metabolism of ingested galactose at rest; effects during exercise are unknown. This study examined whether combined ingestion of galactose and glucose during exercise enhances exogenous galactose oxidation. Fourteen endurance-trained male and female participants [age, 27 (5) yr; V̇o
2peak , 58.1 (7.0) mL·kg-1 ·min-1 ] performed cycle ergometry for 150 min at 50% peak power on four occasions, in a randomized counterbalanced manner. During exercise, they ingested beverages providing carbohydrates at rates of 0.4 g.min-1 galactose (GAL), 0.8 g.min-1 glucose (GLU), and on two occasions 0.8 g.min-1 total galactose-glucose (GAL + GLU; 1:1 ratio). Single-monosaccharide13 C-labeling (*) was used to calculate independent (GAL, GLU, GAL* + GLU, and GAL + GLU*) and combined (GAL* + GLU*, COMBINE) exogenous-monosaccharide oxidation between exercise. Plasma galactose concentrations with GAL + GLU [0.4 mmol.L; 95% confidence limits (CL): 0.1, 0.6] were lower (contrast: 0.5 mmol.L; 95% CL: 0.2, 0.8; P < 0.0001) than when GAL alone (0.9 mmol.L; 95% CL: 0.7, 1.2) was ingested. Exogenous carbohydrate oxidation with GAL alone (0.31 g·min-1 ; 95% CL: 0.28, 0.35) was marginally reduced (contrast: 0.05 g·min-1 ; 95% CL: -0.09, 0.00007; P = 0.01) when combined with glucose (GAL* + GLU 0.27 g·min-1 ; 0.24, 0.30). Total combined exogenous-carbohydrate oxidation (COMBINE: 0.57 g·min-1 ; 95% CL: 0.49, 0.64) was similar (contrast: 0.02 g·min-1 ; 95% CL: -0.05, 0.09; P = 0.63) when compared with isoenergetic GLU (0.55 g·min-1 ; 95% CL: 0.52, 0.58). In conclusion, coingestion of glucose and galactose did not enhance exogenous galactose oxidation during exercise. When combined, isoenergetic galactose-glucose ingestion elicited similar exogenous-carbohydrate oxidation to glucose suggesting galactose-glucose blends are a valid alternative for glucose as an exogenous-carbohydrate source during exercise. NEW & NOTEWORTHY Glucose and galactose coingestion blunted the galactosemia seen with galactose-only ingestion during exercise. Glucose and galactose coingestion did not enhance the oxidation of ingested galactose during exercise. Combined galactose-glucose (1:1 ratio) ingestion was oxidized to a similar extent as isoenergetic glucose-only ingestion during exercise. Galactose-glucose blends are a viable exogenous carbohydrate energy source for ingestion during exercise.- Published
- 2022
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14. Wool keratin - A novel dietary protein source: Nutritional value and toxicological assessment.
- Author
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Dias GJ, Haththotuwa TN, Rowlands DS, Gram M, and Bekhit AEA
- Subjects
- Amino Acids analysis, Animal Feed analysis, Animals, Caseins analysis, Diet veterinary, Dietary Proteins analysis, Nutritive Value, Rats, Sheep, Keratins chemistry, Wool chemistry
- Abstract
Keratin derived protein (KDP) was extracted from sheep wool using high pressure microwave technology and food acids and investigated for its potential as a novel dietary protein. The proximate composition, amino acid profile, element profile, in vitro cytotoxicity and digestibility of KDP were evaluated. Nutritive effects of KDP at 50% dietary supplementation were compared with a casein-based diet in a growing rat model for 95 days. Results indicate KDP to be rich in protein (86%), amino acid cysteine (8.8 g/100 g) and element selenium (0.29 μg/g). KDP was non-cytotoxic in vitro at ≤ 2 mg/mL concentration. There were no differences in the rat's weight gain compared to the control group (P > 0.05). Overall, the inclusion of the KDP in the diet was an effective substitute for casein protein at 50% and KDP has the potential to be used in the food industry as a novel dietary protein, free of fat and carbohydrate., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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15. The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration During Continuous Exercise: A Systematic Meta-Analysis and Perspective.
- Author
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Rowlands DS, Kopetschny BH, and Badenhorst CE
- Subjects
- Bayes Theorem, Humans, Osmolar Concentration, Sodium, Water-Electrolyte Balance, Dehydration therapy, Exercise physiology
- Abstract
Background: Body-fluid loss during prolonged continuous exercise can impair cardiovascular function, harming performance. Delta percent plasma volume (dPV) represents the change in central and circulatory body-water volume and therefore hydration during exercise; however, the effect of carbohydrate-electrolyte drinks and water on the dPV response is unclear., Objective: To determine by meta-analysis the effects of ingested hypertonic (> 300 mOsmol kg
-1 ), isotonic (275-300 mOsmol kg-1 ) and hypotonic (< 275 mOsmol kg-1 ) drinks containing carbohydrate and electrolyte ([Na+ ] < 50 mmol L-1 ), and non-carbohydrate drinks/water (< 40 mOsmol kg-1 ) on dPV during continuous exercise., Methods: A systematic review produced 28 qualifying studies and 68 drink treatment effects. Random-effects meta-analyses with repeated measures provided estimates of effects and probability of superiority (p+ ) during 0-180 min of exercise, adjusted for drink osmolality, ingestion rate, metabolic rate and a weakly informative Bayesian prior., Results: Mean drink effects on dPV were: hypertonic - 7.4% [90% compatibility limits (CL) - 8.5, - 6.3], isotonic - 8.7% (90% CL - 10.1, - 7.4), hypotonic - 6.3% (90% CL - 7.4, - 5.3) and water - 7.5% (90% CL - 8.5, - 6.4). Posterior contrast estimates relative to the smallest important effect (dPV = 0.75%) were: hypertonic-isotonic 1.2% (90% CL - 0.1, 2.6; p+ = 0.74), hypotonic-isotonic 2.3% (90% CL 1.1, 3.5; p+ = 0.984), water-isotonic 1.3% (90% CL 0.0, 2.5; p+ = 0.76), hypotonic-hypertonic 1.1% (90% CL 0.1, 2.1; p+ = 0.71), hypertonic-water 0.1% (90% CL - 0.8, 1.0; p+ = 0.12) and hypotonic-water 1.1% (90% CL 0.1, 2.0; p+ = 0.72). Thus, hypotonic drinks were very likely superior to isotonic and likely superior to hypertonic and water. Metabolic rate, ingestion rate, carbohydrate characteristics and electrolyte concentration were generally substantial modifiers of dPV., Conclusion: Hypotonic carbohydrate-electrolyte drinks ingested continuously during exercise provide the greatest benefit to hydration., (© 2021. The Author(s).)- Published
- 2022
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16. Effects of whey protein on skeletal muscle microvascular and mitochondrial plasticity following 10 weeks of exercise training in men with type 2 diabetes.
- Author
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Gaffney K, Lucero A, Macartney-Coxson D, Clapham J, Whitfield P, Palmer BR, Wakefield S, Faulkner J, Stoner L, and Rowlands DS
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- Adaptation, Physiological drug effects, Adaptation, Physiological physiology, Adult, Aged, Beverages, Diabetes Mellitus, Type 2 therapy, Dietary Supplements, Humans, Male, Microcirculation drug effects, Middle Aged, Mitochondria drug effects, Muscle, Skeletal drug effects, Whey Proteins administration & dosage, Diabetes Mellitus, Type 2 physiopathology, Exercise, Microcirculation physiology, Mitochondria physiology, Muscle, Skeletal physiology, Whey Proteins pharmacology
- Abstract
Skeletal muscle microvascular dysfunction and mitochondrial rarefaction feature in type 2 diabetes mellitus (T2DM) linked to low tissue glucose disposal rate (GDR). Exercise training and milk protein supplementation independently promote microvascular and metabolic plasticity in muscle associated with improved nutrient delivery, but combined effects are unknown. In a randomised-controlled trial, 24 men (55.6 y, SD 5.7) with T2DM ingested whey protein drinks (protein/carbohydrate/fat: 20/10/3 g; WHEY) or placebo (carbohydrate/fat: 30/3 g; CON) before/after 45 mixed-mode intense exercise sessions over 10 weeks, to study effects on insulin-stimulated (hyperinsulinemic clamp) skeletal-muscle microvascular blood flow (mBF) and perfusion (near-infrared spectroscopy), and histological, genetic, and biochemical markers (biopsy) of microvascular and mitochondrial plasticity. WHEY enhanced insulin-stimulated perfusion (WHEY-CON 5.6%; 90% CI -0.1, 11.3), while mBF was not altered (3.5%; -17.5, 24.5); perfusion, but not mBF, associated (regression) with increased GDR. Exercise training increased mitochondrial (range of means: 40%-90%) and lipid density (20%-30%), enzyme activity (20%-70%), capillary:fibre ratio (∼25%), and lowered systolic (∼4%) and diastolic (4%-5%) blood pressure, but without WHEY effects. WHEY dampened PGC1 α -2.9% (90% compatibility interval: -5.7, -0.2) and NOS3 -6.4% (-1.4, -0.2) expression, but other messenger RNA (mRNA) were unclear. Skeletal muscle microvascular and mitochondrial exercise adaptations were not accentuated by whey protein ingestion in men with T2DM. ANZCTR Registration Number: ACTRN12614001197628. Novelty: Chronic whey ingestion in T2DM with exercise altered expression of several mitochondrial and angiogenic mRNA. Whey added no additional benefit to muscle microvascular or mitochondrial adaptations to exercise. Insulin-stimulated perfusion increased with whey but was without impact on glucose disposal.
- Published
- 2021
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17. The Road to the Beijing Winter Olympics and Beyond: Opinions and Perspectives on Physiology and Innovation in Winter Sport.
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Wang J, Guan H, Hostrup M, Rowlands DS, González-Alonso J, and Jensen J
- Abstract
Beijing will host the 2022 Winter Olympics, and China strengthens research on various aspects to allow their athletes to compete successfully in winter sport. Simultaneously, Government-directed initiatives aim to increase public participation in recreational winter sport. These parallel developments allow research to advance knowledge and understanding of the physiological determinants of performance and health related to winter sport. Winter sport athletes often conduct a substantial amount of training with high volumes of low-to-moderate exercise intensity and lower volumes of high-intensity work. Moreover, much of the training occur at low ambient temperatures and winter sport athletes have high risk of developing asthma or asthma-related conditions, such as exercise-induced bronchoconstriction. The high training volumes require optimal nutrition with increased energy and dietary protein requirement to stimulate muscle protein synthesis response in the post-exercise period. Whether higher protein intake is required in the cold should be investigated. Cross-country skiing is performed mostly in Northern hemisphere with a strong cultural heritage and sporting tradition. It is expected that innovative initiatives on recruitment and training during the next few years will target to enhance performance of Chinese athletes in classical endurance-based winter sport. The innovation potential coupled with resourcing and population may be substantial with the potential for China to become a significant winter sport nation. This paper discusses the physiological aspects of endurance training and performance in winter sport highlighting areas where innovation may advance in athletic performance in cold environments. In addition, to ensure sustainable development of snow sport, a quality ski patrol and rescue system is recommended for the safety of increasing mass participation., Competing Interests: Conflict of interestOn behalf of all authors, the corresponding author states that there is no confict of interest., (© The Author(s) 2021.)
- Published
- 2021
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18. An epigenetic clock for human skeletal muscle.
- Author
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Voisin S, Harvey NR, Haupt LM, Griffiths LR, Ashton KJ, Coffey VG, Doering TM, Thompson JM, Benedict C, Cedernaes J, Lindholm ME, Craig JM, Rowlands DS, Sharples AP, Horvath S, and Eynon N
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Young Adult, Epigenomics methods, Muscle, Skeletal physiopathology
- Abstract
Background: Ageing is associated with DNA methylation changes in all human tissues, and epigenetic markers can estimate chronological age based on DNA methylation patterns across tissues. However, the construction of the original pan-tissue epigenetic clock did not include skeletal muscle samples and hence exhibited a strong deviation between DNA methylation and chronological age in this tissue., Methods: To address this, we developed a more accurate, muscle-specific epigenetic clock based on the genome-wide DNA methylation data of 682 skeletal muscle samples from 12 independent datasets (18-89 years old, 22% women, 99% Caucasian), all generated with Illumina HumanMethylation (HM) arrays (HM27, HM450, or HMEPIC). We also took advantage of the large number of samples to conduct an epigenome-wide association study of age-associated DNA methylation patterns in skeletal muscle., Results: The newly developed clock uses 200 cytosine-phosphate-guanine dinucleotides to estimate chronological age in skeletal muscle, 16 of which are in common with the 353 cytosine-phosphate-guanine dinucleotides of the pan-tissue clock. The muscle clock outperformed the pan-tissue clock, with a median error of only 4.6 years across datasets (vs. 13.1 years for the pan-tissue clock, P < 0.0001) and an average correlation of ρ = 0.62 between actual and predicted age across datasets (vs. ρ = 0.51 for the pan-tissue clock). Lastly, we identified 180 differentially methylated regions with age in skeletal muscle at a false discovery rate < 0.005. However, gene set enrichment analysis did not reveal any enrichment for gene ontologies., Conclusions: We have developed a muscle-specific epigenetic clock that predicts age with better accuracy than the pan-tissue clock. We implemented the muscle clock in an r package called Muscle Epigenetic Age Test available on Bioconductor to estimate epigenetic age in skeletal muscle samples. This clock may prove valuable in assessing the impact of environmental factors, such as exercise and diet, on muscle-specific biological ageing processes., (© 2020 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders.)
- Published
- 2020
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19. The Effects of Uniquely-Processed Titanium on Balance and Walking Performance in Healthy Older Adults.
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Black MJ, Lucero AA, Fink PW, Stoner L, Shultz SP, Lark SD, and Rowlands DS
- Abstract
The increased risk of falls associated with advancing age has increased demand for methods to improve balance and mobility. The primary purpose of the study was to determine whether wearing Aqua Titan-treated stockings could improve balance and walking performance in an older population; secondary was to elucidate the mechanisms. In a randomized, double-blind crossover, 16 healthy older adults (age, 67.9 ± 4.2 years; BMI, 24.8 ± 3.1 kg/m²) performed two 4-day trials composed of baseline measures and fatiguing exercise on Day 1, with recovery measures at 14, 38 and 62 h post-exercise, wearing Aqua Titan and control stockings. Balance, walking performance, triceps surae stretch reflex, ankle range of motion and gastrocnemius muscle microvascular perfusion, blood flow and oxygen consumption were measured at baseline and during recovery. Aqua Titan had no effect on the microvascular parameters, but increased total ankle range of motion at 38 h (2.4°; 95% CI ± 1.8°) and 62 h (2.7°; ±1.7°), contributed to by increases in dorsiflexion and plantar flexion. There was decreasing persistence in the medial-lateral center of pressure movement at 38 h (q = 0, −0.0635 ± 0.0455), compared to control stockings. Aqua Titan garments hold potential for improving balance and mobility in older adults in the days following a bout of fatiguing exercise. The proposed mechanisms associated with enhanced sensory feedback require further exploration.
- Published
- 2018
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20. Commentaries on Viewpoint: Principles, insights, and potential pitfalls of the noninvasive determination of muscle oxidative capacity by near-infrared spectroscopy.
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Chung S, Nelson MD, Hamaoka T, Jacobs RA, Pearson J, Subudhi AW, Jenkins NT, Bartlett MF, Fitzgerald LF, Miehm JD, Kent JA, Lucero AA, Rowlands DS, Stoner L, McCully KK, Call J, Rodriguez-Miguelez P, Harris RA, Porcelli S, Rasica L, Marzorati M, Quaresima V, Ryan TE, Vernillo G, Millet GP, Malatesta D, Millet GY, Zuo L, and Chuang CC
- Subjects
- Exercise, Muscles, Oxidative Stress, Oxygen Consumption, Spectroscopy, Near-Infrared
- Published
- 2018
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21. Nil Whey Protein Effect on Glycemic Control after Intense Mixed-Mode Training in Type 2 Diabetes.
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Gaffney KA, Lucero A, Stoner L, Faulkner J, Whitfield P, Krebs J, and Rowlands DS
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- Body Composition, Double-Blind Method, Humans, Insulin Resistance, Male, Middle Aged, Oxygen Consumption, Quadriceps Muscle physiology, Waist Circumference, Blood Glucose analysis, Diabetes Mellitus, Type 2 blood, High-Intensity Interval Training methods, Whey Proteins administration & dosage
- Abstract
Although intense endurance and resistance exercise training and whey protein supplementation have both been shown to independently improve glycemic control, no known studies have examined the effect of high-intensity mixed-mode interval training (MMIT) and whey supplementation in adults with Type 2 diabetes (T2D)., Purpose: This study aimed to determine if peritraining whey protein supplementation combined with MMIT can improve glycemic control., Methods: In a double-blind, randomized, placebo-controlled trial, 24 men (55.7 ± 5.6 yr) with T2D performed MMIT with whey (20 g) or placebo control for 10 wk. Glycemic control was assessed via glucose disposal rate during a euglycemic insulin clamp, fasting blood glucose concentration, and homeostatic model assessment of insulin resistance. Changes in peak oxygen consumption, 1-repetition maximum strength, vastus lateralis muscle, and subcutaneous adipose thicknesses, and waist circumference were also assessed., Results: Ten weeks of MMIT substantially improved glucose disposal rate by 27.5% (90% confidence interval, 1.2%-60.7%) and 24.8% (-5.4% to 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in fasting blood glucose by -17.4% (-30.6% to -1.6%) and homeostatic model assessment of insulin resistance by -14.1% (-25.3% to 1.08%) in the whey group; however, whey effects were not clearly beneficial to glycemic outcomes relative to the control. MMIT also clearly substantially improved 1-repetition maximum by 20.6% (16.3%-24.9%) and 22.7% (18.4%-27.2%), peak oxygen consumption by 22.6% (12.0%-26.2%) and 18.5% (10.5%-27.4%), and vastus lateralis muscle thickness by 18.9% (12.0%-26.2%) and 18.6% (10.5%-27.4%) and possibly reduced waist circumference by -2.1% (-3.1% to -1.0%) and -1.9% (-3.7% to -0.1%) in the control and whey groups, respectively, but the whey-control outcome was trivial or unclear., Conclusions: A clinically meaningful enhancement in glycemic control after 10 wk of MMIT was not clearly advanced with peritraining whey protein supplementation in middle-age men with T2D.
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- 2018
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22. Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.
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Rowlands DS and Houltham SD
- Subjects
- Adolescent, Adult, Body Weight, Competitive Behavior physiology, Cross-Over Studies, Diet, Double-Blind Method, Energy Drinks, Food, Fructose administration & dosage, Gastrointestinal Diseases prevention & control, Glucose administration & dosage, Humans, Male, Middle Aged, Polysaccharides administration & dosage, Temperature, Young Adult, Bicycling physiology, Dietary Carbohydrates administration & dosage, Physical Endurance physiology, Running physiology, Swimming physiology
- Abstract
The ingestion of multiple (2:1 glucose-fructose) transportable carbohydrate in beverages at high rates (>78 g·h) during endurance exercise enhances exogenous carbohydrate oxidation, fluid absorption, gut comfort, and performance relative to glucose alone. However, during long-distance endurance competition, athletes prefer a solid-gel-drink format, and the effect size of multiple-transportable carbohydrate is unknown., Purpose: This study aimed to determine the effect of multiple-transportable carbohydrate on triathlon competition performance when ingested within bars, gels, and drinks., Methods: A double-blind randomized controlled trial was conducted within two national-body sanctioned half-ironman triathlon races held 3 wk apart in 74 well-trained male triathletes (18-60 yr; >2 yr competition experience). Carbohydrate comprising glucose/maltodextrin-fructose (2:1 ratio) or standard isocaloric carbohydrate (glucose/maltodextrin only) was ingested before (94 g) and during the cycle (2.5 g·km) and run (7.8 g·km) sections, averaging 78.6 ± 6.6 g·h, partitioned to bars (25%), gels (35%), and drink (40%). Postrace, 0- to 10-unit Likert-type scales were completed to assess gut comfort and energy., Results: The trial returned low dropout rate (9%), high compliance, and sensitivity (typical error 2.2%). The effect of multiple-transportable carbohydrate on performance time was -0.53% (95% confidence interval = -1.30% to 0.24%; small benefit threshold = -0.54%), with likelihood-based risk analysis supporting adoption (benefit-harm ratio = 48.9%:0.3%; odds ratio = 285:1). Covariate adjustments for preexercise body weight and heat stress had negligible impact performance. Multiple-transportable carbohydrate possibly lowered nausea during the swim and bike; otherwise, effects on gut comfort and perceived energy were negligible., Conclusions: Multiple-transportable (2:1 maltodextrin/glucose-fructose) compared with single-transportable carbohydrate ingested in differing format provided a small benefit to long-distance triathlon performance, inferred as adoption worthy. Large sample in-competition randomized trials offer ecological validity, high participant throughput, compliance, and sensitivity for evaluation of health and performance interventions in athletes.
- Published
- 2017
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23. Solid, Gel, and Liquid Carbohydrate Format Effects on Gut Comfort and Performance.
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Guillochon M and Rowlands DS
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- Adult, Athletes, Cross-Over Studies, Digestion, Double-Blind Method, Exercise Test, Fructose administration & dosage, Gels administration & dosage, Humans, Male, Muscle Fatigue, Polysaccharides administration & dosage, Young Adult, Athletic Performance, Bicycling psychology, Dietary Carbohydrates administration & dosage, Sports Nutritional Physiological Phenomena
- Abstract
Carbohydrate sports drinks produce worthwhile benefits to endurance performance compared with noncaloric controls. However, athletes now consume carbohydrate in a range of formats, including gels and bars, but the comparable performance outcomes are unknown. Therefore, the aim of this study was to establish the relative effects of drink, gel, bar, and mixed carbohydrate formats on intense cycling performance. In a treatmentapparent randomized crossover design, 12 well-trained male cyclists completed 4 trials comprising a 140-min race simulation, followed by a double-blind slow-ramp to exhaustion (0.333 W·s
-1 ). Carbohydrate comprising fructose and maltodextrin was ingested every 20 min via commercial drink, gel, bar, or mix of all 3, providing 80 g carbohydrate·h-1 . Fluid ingestion was 705 ml·h-1 . Exertion, fatigue, and gastrointestinal discomfort were measured with VAS. Performance peak power (SD) was 370 (41), 376 (37), 362 (51) and 368 W (54) for drink, gels, bars, and mix respectively. The reduction in power (-3.9%; 90%CI ±4.3) following bar ingestion vs. gel was likely substantial (likelihood harm 81.2%; benefit 0.8%), but no clear differences between drinks, gels, and the mix were evident. Bars also produced small-moderate standardized increases in nausea, stomach fullness, abdominal cramps, and perceived exertion, relative to gels (likelihood harm 95-99.5%; benefit <0.01%) and drink (75-95%; <0.01%); mix also increased nausea relative to gels (95%; <0.01%). Relative to a gel, carbohydrate bar ingestion reduced peak power, gut comfort, and ease of exertion; furthermore, no clear difference relative to drink suggests bars alone are the less favorable exogenous-carbohydrate energy source for intense endurance performance.- Published
- 2017
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24. Probiotic Streptococcus thermophilus FP4 and Bifidobacterium breve BR03 Supplementation Attenuates Performance and Range-of-Motion Decrements Following Muscle Damaging Exercise.
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Jäger R, Purpura M, Stone JD, Turner SM, Anzalone AJ, Eimerbrink MJ, Pane M, Amoruso A, Rowlands DS, and Oliver JM
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- Adult, Dietary Supplements, Double-Blind Method, Humans, Male, Muscle, Skeletal, Young Adult, Athletic Performance, Bifidobacterium breve, Myalgia prevention & control, Probiotics, Range of Motion, Articular, Resistance Training, Streptococcus thermophilus
- Abstract
Probiotics have immunomodulatory effects. However, little is known about the potential benefit of probiotics on the inflammation subsequent to strenuous exercise. In a double-blind, randomized, placebo controlled, crossover design separated by a 21-day washout, 15 healthy resistance-trained men ingested an encapsulated probiotic Streptococcus ( S. ) thermophilus FP4 and Bifidobacterium ( B. ) breve BR03 at 5 bn live cells (AFU) concentration each, or a placebo, daily for 3 weeks prior to muscle-damaging exercise (ClinicalTrials.gov NCT02520583). Isometric strength, muscle soreness, range of motion and girth, and blood interleukin-6 (IL-6) and creatine kinase (CK) concentrations were measured from pre- to 72 h post-exercise. Statistical analysis was via mixed models and magnitude-based inference to the standardized difference. Probiotic supplementation resulted in an overall decrease in circulating IL-6, which was sustained to 48 h post-exercise. In addition, probiotic supplementation likely enhanced isometric average peak torque production at 24 to 72 h into the recovery period following exercise (probiotic-placebo point effect ±90% CI: 24 h, 11% ± 7%; 48 h, 12% ± 18%; 72 h, 8% ± 8%). Probiotics also likely moderately increased resting arm angle at 24 h (2.4% ± 2.0%) and 48 h (1.9% ± 1.9%) following exercise, but effects on soreness and flexed arm angle and CK were unclear. These data suggest that dietary supplementation with probiotic strains S. thermophilus FP4 and B. breve BR03 attenuates performance decrements and muscle tension in the days following muscle-damaging exercise., Competing Interests: J.D.S., S.M.T., A.J.A., D.S.R., and J.M.O. declare no competing interests. M.Pa. and A.A. are employed by Biolab Research S.r.l., Probiotical S.p.A.’s holding company. R.J. and M.Pu. are consultants of Pharmachem Laboratories, Inc., Kearny, NJ, USA, which engages in business trade with Probiotical S.p.A.
- Published
- 2016
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25. Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.
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Oliver JM, Almada AL, Van Eck LE, Shah M, Mitchell JB, Jones MT, Jagim AR, and Rowlands DS
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- Double-Blind Method, Humans, Kinetics, Molecular Weight, Placebos, Carbohydrates chemistry
- Abstract
Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373)., Competing Interests: Anthony Almada is the founder and CEO of Vitargo Global Sciences, Inc. Mr. Almada was not involved in any data collection or subsequent analysis. The study was independently designed, conducted, and analyzed without input from Mr. Almada. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials
- Published
- 2016
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26. Protein-leucine ingestion activates a regenerative inflammo-myogenic transcriptome in skeletal muscle following intense endurance exercise.
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Rowlands DS, Nelson AR, Raymond F, Metairon S, Mansourian R, Clarke J, Stellingwerff T, and Phillips SM
- Subjects
- Adult, Gene Regulatory Networks, Humans, Male, Models, Biological, Multigene Family, Muscle, Skeletal metabolism, Oligonucleotide Array Sequence Analysis, Reproducibility of Results, Software, Exercise, Inflammation genetics, Leucine administration & dosage, Muscle Development genetics, Muscle, Skeletal pathology, Physical Endurance, Transcriptome genetics
- Abstract
Protein-leucine supplement ingestion following strenuous endurance exercise accentuates skeletal-muscle protein synthesis and adaptive molecular responses, but the underlying transcriptome is uncharacterized. In a randomized single-blind triple-crossover design, 12 trained men completed 100 min of high-intensity cycling then ingested 70/15/180/30 g protein-leucine-carbohydrate-fat (15LEU), 23/5/180/30 g (5LEU), or 0/0/274/30 g (CON) beverages during the first 90 min of a 240 min recovery period. Vastus lateralis muscle samples (30 and 240 min postexercise) underwent transcriptome analysis by microarray followed by bioinformatic analysis. Gene expression was regulated by protein-leucine in a dose-dependent manner affecting the inflammatory response and muscle growth and development. At 30 min, 15LEU and 5LEU vs. CON activated transcriptome networks with gene-set functions involving cell-cycle arrest (Z-score 2.0-2.7, P < 0.01), leukocyte maturation (1.7, P = 0.007), cell viability (2.4, P = 0.005), promyogenic networks encompassing myocyte differentiation and myogenin (MYOD1, MYOG), and a proteinaceous extracellular matrix, adhesion, and development program correlated with plasma lysine, arginine, tyrosine, taurine, glutamic acid, and asparagine concentrations. High protein-leucine dose (15LEU-5LEU) activated an IL-1I-centered proinflammatory network and leukocyte migration, differentiation, and survival functions (2.0-2.6, <0.001). By 240 min, the protein-leucine transcriptome was anti-inflammatory and promyogenic (IL-6, NF- β, SMAD, STAT3 network inhibition), with overrepresented functions including decreased leukocyte migration and connective tissue development (-1.8-2.4, P < 0.01), increased apoptosis of myeloid and muscle cells (2.2-3.0, P < 0.002), and cell metabolism (2.0-2.4, P < 0.01). The analysis suggests protein-leucine ingestion modulates inflammatory-myogenic regenerative processes during skeletal muscle recovery from endurance exercise. Further cellular and translational research is warranted to validate amino acid-mediated myeloid and myocellular mechanisms within skeletal-muscle functional plasticity., (Copyright © 2016 the American Physiological Society.)
- Published
- 2016
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27. Novel Form of Curcumin Improves Endothelial Function in Young, Healthy Individuals: A Double-Blind Placebo Controlled Study.
- Author
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Oliver JM, Stoner L, Rowlands DS, Caldwell AR, Sanders E, Kreutzer A, Mitchell JB, Purpura M, and Jäger R
- Abstract
Curcumin, a turmeric extract, may protect against cardiovascular diseases by enhancing endothelial function. In this randomized controlled double-blind parallel prospective study, fifty-nine healthy adults were assigned to placebo, 50 mg (50 mg), or 200 mg (200 mg) curcumin, for 8 weeks. The higher curcumin (200 mg) supplementation produced a dose-mediated improvement in endothelial function measured by flow-mediated dilation (FMD). The outcome was a clinically substantial 3.0% increase (90% CI 0.7 to 5.3%, p = 0.032; benefit : harm odds ratio 546 : 1) with the 200 mg dose, relative to placebo. The 50 mg dose also increased FMD relative to placebo by 1.7% (-0.6 to 4.0%, p = 0.23; 25 : 1), but the outcome was not clinically decisive. In apparently healthy adults, 8 weeks of 200 mg oral curcumin supplementation resulted in a clinically meaningful improvement in endothelial function as measured by FMD. Oral curcumin supplementation may present a simple lifestyle strategy for decreasing the risk of cardiovascular diseases. This trial was registered at ISRCTN registry (ISRCTN90184217).
- Published
- 2016
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28. Fructose-Glucose Composite Carbohydrates and Endurance Performance: Critical Review and Future Perspectives.
- Author
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Rowlands DS, Houltham S, Musa-Veloso K, Brown F, Paulionis L, and Bailey D
- Subjects
- Dietary Carbohydrates metabolism, Fructose metabolism, Gastric Emptying, Gastrointestinal Absorption, Glucose metabolism, Humans, Liver metabolism, Maltose metabolism, Muscle, Skeletal metabolism, Oxidation-Reduction, Polysaccharides metabolism, Taste, Beverages, Dietary Carbohydrates administration & dosage, Fructose administration & dosage, Glucose administration & dosage, Maltose administration & dosage, Physical Endurance physiology, Polysaccharides administration & dosage
- Abstract
Sports beverages formulated with fructose and glucose composites enhance exogenous carbohydrate oxidation, gut comfort, and endurance performance, relative to single-saccharide formulations. However, a critical review of performance data is absent. We conducted a comprehensive literature review of the effect of fructose:glucose/maltodextrin (glucose or maltodextrin) composites versus glucose/maltodextrin on endurance performance. Mechanistic associations were drawn from effects on carbohydrate metabolism, gut, and other sensory responses. Overall, 14 studies contained estimates of 2.5-3.0-h endurance performance in men, mostly in cycling. Relative to isocaloric glucose/maltodextrin, the ingestion of 0.5-1.0:1-ratio fructose:glucose/maltodextrin beverages at 1.3-2.4 g carbohydrate·min(-1) produced small to moderate enhancements (1-9 %; 95 % confidence interval 0-19) in mean power. When 0.5:1-ratio composites were ingested at ≥1.7 g·min(-1), improvements were larger (4-9 %; 2-19) than at 1.4-1.6 g·min(-1) (1-3 %; 0-6). The effect sizes at higher ingestion rates were associated with increased exogenous carbohydrate oxidation rate, unilateral fluid absorption, and lower gastrointestinal distress, relative to control. Solutions containing a 0.7-1.0:1 fructose:glucose ratio were absorbed fastest; when ingested at 1.5-1.8 g·min(-1), a 0.8:1 fructose:glucose ratio conveyed the highest exogenous carbohydrate energy and endurance power compared with lower or higher fructose:glucose ratios. To conclude, ingesting 0.5-1.0:1-ratio fructose:glucose/maltodextrin beverages at 1.3-2.4 g·min(-1) likely benefits 2.5-3.0 h endurance power versus isocaloric single saccharide. Further ratio and dose-response research should determine if meaningful performance benefits of composites accrue with ingestion <1.3 g·min(-1), relative to higher doses. Effects should be established in competition, females, other food formats, and in heat-stress and ultra-endurance exercise where carbohydrate demands may differ from the current analysis.
- Published
- 2015
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29. Curcumin supplementation likely attenuates delayed onset muscle soreness (DOMS).
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Nicol LM, Rowlands DS, Fazakerly R, and Kellett J
- Subjects
- Adolescent, Adult, Cross-Over Studies, Double-Blind Method, Exercise physiology, Humans, Inflammation prevention & control, Interleukin-6 metabolism, Male, Pain etiology, Pain Measurement, Physical Education and Training methods, Psychomotor Performance drug effects, Treatment Outcome, Weight Lifting physiology, Young Adult, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Curcumin pharmacology, Dietary Supplements, Myalgia prevention & control
- Abstract
Introduction: Oral curcumin decreases inflammatory cytokines and increases muscle regeneration in mice., Purpose: To determine effects of curcumin on muscle damage, inflammation and delayed onset muscle soreness (DOMS) in humans., Method: Seventeen men completed a double-blind randomized-controlled crossover trial to estimate the effects of oral curcumin supplementation (2.5 g twice daily) versus placebo on single-leg jump performance and DOMS following unaccustomed heavy eccentric exercise. Curcumin or placebo was taken 2 d before to 3 d after eccentric single-leg press exercise, separated by 14-d washout. Measurements were made at baseline, and 0, 24 and 48-h post-exercise comprising: (a) limb pain (1-10 cm visual analogue scale; VAS), (b) muscle swelling, (c) single-leg jump height, and (d) serum markers of muscle damage and inflammation. Standardized magnitude-based inference was used to define outcomes., Results: At 24 and 48-h post-exercise, curcumin caused moderate-large reductions in pain during single-leg squat (VAS scale -1.4 to -1.7; 90 %CL: ±1.0), gluteal stretch (-1.0 to -1.9; ±0.9), squat jump (-1.5 to -1.1; ± 1.2) and small reductions in creatine kinase activity (-22-29 %; ±21-22 %). Associated with the pain reduction was a small increase in single-leg jump performance (15 %; 90 %CL ± 12 %). Curcumin increased interleukin-6 concentrations at 0-h (31 %; ±29 %) and 48-h (32 %; ±29 %) relative to baseline, but decreased IL-6 at 24-h relative to post-exercise (-20 %; ±18 %)., Conclusions: Oral curcumin likely reduces pain associated with DOMS with some evidence for enhanced recovery of muscle performance. Further study is required on mechanisms and translational effects on sport or vocational performance.
- Published
- 2015
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30. Muscular strength, aerobic capacity, and adipocytokines in obese youth after resistance training: A pilot study.
- Author
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Shultz SP, Dahiya R, Leong GM, Rowlands DS, Hills AP, and Byrne NM
- Abstract
Background: Exercise has shown positive training effects on obesity-related inflammation, however, resistance training has shown mixed results concerning adipocytokine levels., Aims: The purpose of this pilot study was to explore the effects of resistance training on blood adipocytokine concentrations in obese youth, with specific examination of the relationship between these biomarkers and improved fitness (i.e., aerobic capacity, muscular strength)., Methods: Fourteen obese adolescents (16.1 ±1.6 y; BMI: 32.3 ±3.9 kg/m(2)) participated in a 16-week resistance training intervention. Body composition, fasting blood concentrations of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-ɑ), adiponectin, and leptin were measured pre- and post-training. Aerobic capacity was assessed via a maximal discontinuous exercise test. The rate of gain in muscular strength was calculated as the slope of progression in 1-repetition maximum throughout the intervention., Results: Resistance training increased lean mass (total, trunk) and decreased per cent body fat (total, trunk). The training also caused moderate clear decreases in IL-6 and TNF-ɑ concentrations. A small increase in adiponectin was also observed before and after intervention. When the group was stratified by changes in aerobic capacity, there were substantially larger decreases in leptin levels for those with improved capacity. Correlation analyses also revealed a negative relationship between log-transformed leptin and aerobic capacity at rest. Improvement in quadriceps strength was positively correlated with IL-6 and TNF-ɑ, while improvement in shoulder adductor strength was positively correlated with IL-6 only., Conclusion: Resistance training improved adipocytokine markers, which were partially associated with improved physical fitness. Specifically, the relationship between strength improvements and IL-6 and TNF-ɑ suggests an exercise-induced signalling pathway that results in overall adaptive decreases in systemic inflammation in obese youth.
- Published
- 2015
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31. High-protein, low-fat, short-term diet results in less stress and fatigue than moderate-protein moderate-fat diet during weight loss in male weightlifters: a pilot study.
- Author
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Helms ER, Zinn C, Rowlands DS, Naidoo R, and Cronin J
- Subjects
- Adult, Affect, Anthropometry, Athletes psychology, Caloric Restriction psychology, Diet, Fat-Restricted psychology, Diet, Reducing psychology, Dietary Fats administration & dosage, Dietary Proteins administration & dosage, Double-Blind Method, Exercise psychology, Fatigue etiology, Humans, Male, Muscle Strength drug effects, Resistance Training, Sports Nutritional Physiological Phenomena, Stress, Psychological etiology, Weight Lifting psychology, Young Adult, Diet psychology, Dietary Proteins therapeutic use, Exercise physiology, Fatigue prevention & control, Stress, Psychological prevention & control, Weight Lifting physiology, Weight Loss physiology
- Abstract
Purpose: Athletes risk performance and muscle loss when dieting. Strategies to prevent losses are unclear. This study examined the effects of two diets on anthropometrics, strength, and stress in athletes., Methods: This double-blind crossover pilot study began with 14 resistance-trained males (20-43 yr) and incurred one dropout. Participants followed carbohydrate-matched, high-protein low-fat (HPLF) or moderate-protein moderate-fat (MPMF) diets of 60% habitual calories for 2 weeks. Protein intakes were 2.8g/kg and 1.6g/kg and mean fat intakes were 15.4% and 36.5% of calories, respectively. Isometric midthigh pull (IMTP) and anthropometrics were measured at baseline and completion. The Daily Analysis of Life Demands of Athletes (DALDA) and Profile of Mood States (POMS) were completed daily. Outcomes were presented statistically as probability of clinical benefit, triviality, or harm with effect sizes (ES) and qualitative assessments., Results: Differences of effect between diets on IMTP and anthropometrics were likely or almost certainly trivial, respectively. Worse than normal scores on DALDA part A, part B and the part A "diet" item were likely more harmful (ES 0.32, 0.4 and 0.65, respectively) during MPMF than HPLF. The POMS fatigue score was likely more harmful (ES 0.37) and the POMS total mood disturbance score (TMDS) was possibly more harmful (ES 0.29) during MPMF than HPLF., Conclusions: For the 2 weeks observed, strength and anthropometric differences were minimal while stress, fatigue, and diet-dissatisfaction were higher during MPMF. A HPLF diet during short-term weight loss may be more effective at mitigating mood disturbance, fatigue, diet dissatisfaction, and stress than a MPMF diet.
- Published
- 2015
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32. Protein-leucine fed dose effects on muscle protein synthesis after endurance exercise.
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Rowlands DS, Nelson AR, Phillips SM, Faulkner JA, Clarke J, Burd NA, Moore D, and Stellingwerff T
- Subjects
- Adult, Amino Acids, Essential blood, Beverages, Blood Glucose metabolism, Cross-Over Studies, Dietary Carbohydrates administration & dosage, Dietary Fats administration & dosage, Dietary Proteins metabolism, Humans, Insulin blood, Leucine blood, Male, Mechanistic Target of Rapamycin Complex 1, Multiprotein Complexes metabolism, Muscle, Skeletal metabolism, Myofibrils metabolism, Single-Blind Method, TOR Serine-Threonine Kinases metabolism, Dietary Proteins administration & dosage, Leucine administration & dosage, Muscle Proteins biosynthesis, Physical Endurance physiology
- Abstract
Unlabelled: Protein-leucine ingestion after strenuous endurance exercise accentuates muscle protein synthesis and improves recovery of muscle performance., Purpose: The objective of this study is to determine whether a low-dose protein-leucine blend ingested after endurance exercise enhances skeletal muscle myofibrillar protein fractional synthetic rate (FSR)., Method: In a crossover design, 12 trained men completed 100 min of high-intensity cycling, then ingested either 70/15/180/30 g of protein/leucine/carbohydrate/fat (15LEU), 23/5/180/30 g of 5LEU, or 0/0/274/30 g of CON beverages in randomized order in four servings during the first 90 min of a 240-min recovery period. Muscle biopsies were collected at 30 and 240 min into recovery with FSR determined by L-[ring-13C6]phenylalanine incorporation and mTORC1 pathway phosphorylation by Western blot., Results: The 33% (90% CL, ±12%) increase in FSR with 5LEU (mean, SD: 0.080, 0.014%·h(-1)) versus CON (0.060, 0.012%·h(-1)) represented near-maximal FSR stimulation. Tripling protein-leucine dose (15LEU: 0.090, 0.11%·h(-1)) negligibly increased FSR (13%, ±12% vs 5LEU). Despite similar FSR, mTORC1(Ser2448) phosphorylation only increased with 15LEU at 30 min, whereas p70S6K(Thr389), rpS6(Ser240/244), and 4E-BP1γ(Ser112) phosphorylation increased with protein-leucine quantity at one or both time points. Plasma leucine and essential amino acid concentrations decreased during recovery in CON but increased with protein-leucine dose. Serum insulin was increased in 15LEU versus CON (60%, ±20%) but was unaffected relative to 5LEU. Regression analysis revealed p70S6K-rpS6 phosphorylation moderately predicted FSR, but the associations with plasma leucine and essential amino acids were small., Conclusions: Ingesting 23 g of protein with 5 g of added leucine achieved near-maximal FSR after endurance exercise, an effect unlikely attributable to mTORC1-S6K-rpS6 signaling, insulin, or amino acids. Translating the effects of protein-leucine quantity on protein synthesis to optimizing adaptation and performance requires further research.
- Published
- 2015
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33. Multi-omic integrated networks connect DNA methylation and miRNA with skeletal muscle plasticity to chronic exercise in Type 2 diabetic obesity.
- Author
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Rowlands DS, Page RA, Sukala WR, Giri M, Ghimbovschi SD, Hayat I, Cheema BS, Lys I, Leikis M, Sheard PW, Wakefield SJ, Breier B, Hathout Y, Brown K, Marathi R, Orkunoglu-Suer FE, Devaney JM, Leiken B, Many G, Krebs J, Hopkins WG, and Hoffman EP
- Subjects
- Diabetes Mellitus, Type 2 complications, Epigenesis, Genetic, Female, Gene Expression Regulation, Glucose metabolism, Humans, Lipid Metabolism, Male, MicroRNAs metabolism, Middle Aged, Muscle, Skeletal blood supply, Muscle, Skeletal ultrastructure, Obesity complications, Phenotype, Physical Endurance genetics, Proteomics, RNA, Messenger genetics, RNA, Messenger metabolism, Resistance Training, Transcriptome genetics, DNA Methylation genetics, Diabetes Mellitus, Type 2 genetics, Exercise, Gene Regulatory Networks, MicroRNAs genetics, Muscle, Skeletal pathology, Obesity genetics
- Abstract
Epigenomic regulation of the transcriptome by DNA methylation and posttranscriptional gene silencing by miRNAs are potential environmental modulators of skeletal muscle plasticity to chronic exercise in healthy and diseased populations. We utilized transcriptome networks to connect exercise-induced differential methylation and miRNA with functional skeletal muscle plasticity. Biopsies of the vastus lateralis were collected from middle-aged Polynesian men and women with morbid obesity (44 kg/m(2) ± 10) and Type 2 diabetes before and following 16 wk of resistance (n = 9) or endurance training (n = 8). Longitudinal transcriptome, methylome, and microRNA (miRNA) responses were obtained via microarray, filtered by novel effect-size based false discovery rate probe selection preceding bioinformatic interrogation. Metabolic and microvascular transcriptome topology dominated the network landscape following endurance exercise. Lipid and glucose metabolism modules were connected to: microRNA (miR)-29a; promoter region hypomethylation of nuclear receptor factor (NRF1) and fatty acid transporter (SLC27A4), and hypermethylation of fatty acid synthase, and to exon hypomethylation of 6-phosphofructo-2-kinase and Ser/Thr protein kinase. Directional change in the endurance networks was validated by lower intramyocellular lipid, increased capillarity, GLUT4, hexokinase, and mitochondrial enzyme activity and proteome. Resistance training also lowered lipid and increased enzyme activity and caused GLUT4 promoter hypomethylation; however, training was inconsequential to GLUT4, capillarity, and metabolic transcriptome. miR-195 connected to negative regulation of vascular development. To conclude, integrated molecular network modelling revealed differential DNA methylation and miRNA expression changes occur in skeletal muscle in response to chronic exercise training that are most pronounced with endurance training and topographically associated with functional metabolic and microvascular plasticity relevant to diabetes rehabilitation., (Copyright © 2014 the American Physiological Society.)
- Published
- 2014
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34. Republished research: Impact of autologous blood injections in treatment of mid-portion Achilles tendinopathy: double blind randomised controlled trial.
- Author
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Bell KJ, Fulcher ML, Rowlands DS, and Kerse N
- Abstract
Study Question: Do peritendinous autologous blood injections improve pain and function in people with mid-portion Achilles tendinopathy?, Summary Answer: The administration of two unguided peritendinous autologous blood injections one month apart, in addition to a standardised eccentric training programme, provides no additional benefit in the treatment of mid-portion Achilles tendinopathy., What Is Known and What This Paper Adds: Several studies have suggested that injection of autologous blood can help in the treatment of various tendinopathies. There is a lack of high quality evidence showing relevant benefit for autologous blood injections, particularly in the management of mid-portion Achilles tendinopathy. We found no additional reduction in pain or improvement in function when these injections were combined with an eccentric calf training programme., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)
- Published
- 2014
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35. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes.
- Author
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Helms ER, Zinn C, Rowlands DS, and Brown SR
- Subjects
- Adipose Tissue metabolism, Body Fluid Compartments metabolism, Body Weight, Dietary Proteins pharmacology, Female, Humans, Male, Nutritional Requirements, Sports, Athletes, Body Composition drug effects, Caloric Restriction, Dietary Proteins administration & dosage, Energy Intake, Resistance Training, Sports Nutritional Physiological Phenomena
- Abstract
Unlabelled: Caloric restriction occurs when athletes attempt to reduce body fat or make weight. There is evidence that protein needs increase when athletes restrict calories or have low body fat., Purpose: The aims of this review were to evaluate the effects of dietary protein on body composition in energy-restricted resistance-trained athletes and to provide protein recommendations for these athletes., Methods: Database searches were performed from earliest record to July 2013 using the terms protein, and intake, or diet, and weight, or train, or restrict, or energy, or strength, and athlete. Studies (N = 6) needed to use adult (≥ 18 yrs), energy-restricted, resistance-trained (> 6 months) humans of lower body fat (males ≤ 23% and females ≤ 35%) performing resistance training. Protein intake, fat free mass (FFM) and body fat had to be reported., Results: Body fat percentage decreased (0.5-6.6%) in all study groups (N = 13) and FFM decreased (0.3-2.7kg) in nine of 13. Six groups gained, did not lose, or lost nonsignificant amounts of FFM. Five out of these six groups were among the highest in body fat, lowest in caloric restriction, or underwent novel resistance training stimuli. However, the one group that was not high in body fat that underwent substantial caloric restriction, without novel training stimuli, consumed the highest protein intake out of all the groups in this review (2.5-2.6g/kg)., Conclusions: Protein needs for energy-restricted resistance-trained athletes are likely 2.3-3.1g/kg of FFM scaled upwards with severity of caloric restriction and leanness.
- Published
- 2014
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36. A snapshot of nitrogen balance in endurance-trained women.
- Author
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Houltham SD and Rowlands DS
- Subjects
- Adult, Female, Humans, Nitrogen metabolism, Physical Endurance physiology, Sports physiology
- Abstract
Indirect estimates of the mean daily protein requirement for female endurance athletes are 1.2-1.4 g·kg(-1)·day(-1); however, an empirical estimate using nitrogen balance is absent. A 72-h nitrogen balance was determined during the mid-follicular phase of 10 female cyclists and triathletes training for 10.8 h·week(-1) (SD 2.8) following 2 habituated protein intakes: (i) normal habitual (NH) (protein 85 g·day(-1)), and (ii) isocaloric high-protein (HP) (∼2-fold increase in protein). Total 72-h nitrogen intake was determined from Leco total combustion of ingested food samples. Nitrogen loss was determined from micro-Kjeldahl analysis of 72-h total urinary nitrogen and representative resting and exercise sweat output, plus estimates for fecal and miscellaneous losses. Habituated (steady state) protein requirement was estimated from the mean regression of adapted nitrogen balance vs nitrogen intake. Mean (SD) 24-h dietary protein and energy intake was NH: 1.4 g·kg(-1)·day(-1) (0.2), energy: 9078 kJ·day(-1) (1492), HP: 2.7 g·kg(-1)·day(-1) (0.3) 8909 kJ·day(-1) (1411). Average 24-h urinary nitrogen and sweat urea nitrogen outputs were 13.2 g·day(-1) (2.4) and 0.33 g·day(-1) (0.08) in NH; 21.5 g·day(-1) (3.9) and 0.54 g·day(-1) (0.12) in HP, respectively. Nitrogen balance was negative in NH (-0.59 gN·day(-1) SD 1.64) but positive in HP (2.69 gN·day(-1) SD 3.09). Estimated mean protein requirement was 1.63 g·kg(-1)·day(-1) (95% confidence interval: 1.1-3.8). In conclusion the snapshot of follicular phase dietary protein requirement conformed with previous estimates for men, but was higher than previous nonempirical estimates for endurance-training women; low self-selected energy and carbohydrate intakes may explain the higher than expected nitrogen turnover, and consequently protein requirement.
- Published
- 2014
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37. The effects of uniquely-processed titanium on biological systems: implications for human health and performance.
- Author
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Rowlands DS, Shultz SP, Ogawa T, Aoi W, and Korte M
- Abstract
Titanium is biocompatible and widely utilized in a variety of applications. Recently, titanium in pico-nanometer scale and soluble form (Aqua Titan) has expanded its use to applied human health and performance. The purpose of this article is to review the current evidence associated with specific physiological responses to Aqua Titan-treated materials. In vitro studies have shown that application of Aqua Titan can modify membrane potential and long-term potentiation in isolated hippocampal neurons, suggesting reduced pain memory as a possible mechanism for reported analgesia. Proximal contact with Aqua Titan-treated titanium increased gene expression, protein synthesis, cell growth and adhesion in normal cultured muscle and bone cells, suggesting application for Aqua Titan in clinical implant procedures and wound healing. Evidence for beneficial effects on neuromuscular control of muscle-tendon function and improvements in running economy in human athletes was seen when Aqua Titan-treated tape was applied to the human triceps surae following fatigue induced by prior strenuous exercise. Finally, behavioral responses and effects on the autonomic nervous system to environmental exposure suggest Aqua Titan may promote a mild relaxant, or stress-suppressive response. Together, data suggest exposure to Aqua Titan-treated materials modulates aspects of growth and function in neuronal and other musculoskeletal cells with possible benefits to musculotendinous recovery from exercise and to the systemic response to stress.
- Published
- 2014
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38. Effect of whole-body microtitanium-treated garments on metabolic cost of exercise following strenuous hill running.
- Author
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Rowlands DS, Graham DF, Fink PW, Wadsworth DP, and Hughes JD
- Subjects
- Adult, Cross-Over Studies, Double-Blind Method, Healthy Volunteers, Humans, Male, Young Adult, Clothing, Energy Metabolism drug effects, Exercise, Running, Titanium administration & dosage
- Abstract
Objectives: To determine the effect size of wearing sports garments treated with microscopic titanium particles (AQUA TITAN) during recovery from strenuous running on the restoration of running economy during subsequent exercise., Design: A double-blind crossover was used to determine the effect of AQUA TITAN on running metabolic cost in 10 healthy men. Participants performed 40 min of treadmill running comprising 2×(10 min at 5% and 10 min at -10% grade), followed by random allocation to skin-tight nylon-polyurethane AQUA TITAN treated or non-treated placebo garments covering the torso, limbs, and feet. Garments were worn continuously throughout the next 48-h, during which time participants rested (day 2) then completed a graded treadmill run to determine metabolic outcome (day 3)., Methods: Body-weight normalised running metabolic cost was evaluated by indirect calorimetry and the effect size referenced against the smallest meaningful change in economy (0.9%) for improvement in distance running performance., Results: The fatigue effect while wearing control garments on metabolic cost at 48-h was small (2.2% 95%CL ±1.2%). In contrast, AQUA TITAN garments most certainly reduced running metabolic cost (-3.1% ±0.9%) vs. control. Additionally, AQUA TITAN increased the respiratory exchange ratio (0.011 ±0.005) and lowered minute ventilation at intensities below the ventilatory threshold (-4.0% ±0.9%)., Conclusions: AQUA TITAN garments worn during recovery from strenuous exercise improved subsequent running economy to a magnitude likely to restore endurance performance. Future research should verify the magnitude of garment effects on performance outcomes, and on identifying the acute or passive neural, musculotendinous or metabolic mechanisms responsible., (Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2014
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39. Effect of microtitanium impregnated tape on the recovery of triceps surae musculotendinous function following strenuous running.
- Author
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Hughes JD, Fink PW, Graham DF, and Rowlands DS
- Abstract
We previously reported increased running economy and joint range of motion (ROM) during subsequent exercise performed 48-h following strenuous exercise while wearing garments containing micro-titanium particles generated from high-pressure aqueous processing of titanium (AQUA TITAN(TM)). Here we utilised an isolated plantarflexion triceps surae model and AQUA TITAN-treated flexible tape to determine if dermal application of the micro-titanium could account for meaningful changes in functional properties of the musculotendinous unit. In a randomised double-blind crossover, 20 trained men day 1, baseline measures, AQUA TITAN or placebo tape covering the triceps surae, intermittent high-intensity treadmill running; day 2, rest; day 3, post-stress post-treatment outcome measures. Outcomes comprised: plantarflexion ROM via isokinetic dynamometry; short latency reflex from electromyography; Achilles tendon stiffness from isometric dynamometry, ultrasonography (Achilles-medial-gastrocnemius junction), motion analysis, and force-length modelling. High-intensity exercise with placebo tape reduced tendon stiffness (-16.5%; 95% confidence limits ±8.1%; small effect size), relative to non-taped baseline, but this effect was negligible (-5.9%; ±9.2%) with AQUA TITAN (AQUA TITAN-placebo difference -11.3%; ±11.6%). Change in latency relative to baseline was trivial with placebo (1.6%; ±3.8%) but large with AQUA TITAN (-11.3%; ±3.3%). The effects on ROM with AQUA TITAN (1.6%; ±2.0%) and placebo were trivial (-1.6% ±1.9%), but the small difference (3.1%; ±2.7%) possibly greater with AQUA TITAN. AQUA TITAN tape accelerated the reflex response and attenuated reduced Achilles tendon stiffness following fatiguing exercise. Altered neuromuscular control of tendon stiffness via dermal application of micro-titanium treated materials may facilitate restoration of musculotendinous contractile performance following prior strenuous exercise.
- Published
- 2013
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40. Effect of post-exercise protein-leucine feeding on neutrophil function, immunomodulatory plasma metabolites and cortisol during a 6-day block of intense cycling.
- Author
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Nelson AR, Jackson L, Clarke J, Stellingwerff T, Broadbent S, and Rowlands DS
- Subjects
- Adult, Amino Acids blood, Amino Acids immunology, Cross-Over Studies, Dietary Carbohydrates immunology, Dietary Carbohydrates metabolism, Dietary Supplements, Double-Blind Method, Humans, Hydrocortisone immunology, Immunologic Factors metabolism, Interleukin-10 blood, Interleukin-10 immunology, Interleukin-6 blood, Interleukin-6 immunology, Leucine immunology, Lipid Metabolism immunology, Lipid Metabolism physiology, Male, Milk Proteins immunology, Muscle Proteins immunology, Muscle, Skeletal immunology, Muscle, Skeletal metabolism, Neutrophils metabolism, Oxygen immunology, Oxygen metabolism, Superoxides blood, Superoxides immunology, Testosterone blood, Testosterone immunology, Whey Proteins, Exercise physiology, Hydrocortisone blood, Immunologic Factors immunology, Leucine metabolism, Milk Proteins metabolism, Muscle Proteins metabolism, Neutrophils immunology
- Abstract
Whey protein and leucine ingestion following exercise increases muscle protein synthesis and could influence neutrophil function during recovery from prolonged intense exercise. We examined the effects of whey protein and leucine ingestion post-exercise on neutrophil function and immunomodulators during a period of intense cycling. In a randomized double-blind crossover, 12 male cyclists ingested protein/leucine/carbohydrate/fat (LEUPRO 20/7.5/89/22 g h(-1), respectively) or isocaloric carbohydrate/fat control (CON 119/22 g h(-1)) beverages for 1-3 h post-exercise during 6 days of high-intensity training. Blood was taken pre- and post-exercise on days 1, 2, 4 and 6 for phorbol myristate acetate (PMA)-stimulated neutrophil superoxide (O2 (-)) production, immune cell counts, amino acid and lipid metabolism via metabolomics, hormones (cortisol, testosterone) and cytokines (interleukin-6, interleukin-10). During recovery on day 1, LEUPRO ingestion increased mean concentrations of plasma amino acids (glycine, arginine, glutamine, leucine) and myristic acid metabolites (acylcarnitines C14, myristoylcarnitine; and C14:1-OH, hydroxymyristoleylcarnitine) with neutrophil priming capacity, and reduced neutrophil O2 production (15-17 mmol O2 (-) cell(-1) ± 90 % confidence limits 20 mmol O2 (-) cell(-1)). On day 2, LEUPRO increased pre-exercise plasma volume (6.6 ± 3.8 %) but haematological effects were trivial. LEUPRO supplementation did not substantially alter neutrophil elastase, testosterone, or cytokine concentrations. By day 6, however, LEUPRO reduced pre-exercise cortisol 21 % (±15 %) and acylcarnitine C16 (palmitoylcarnitine) during exercise, and increased post-exercise neutrophil O2 (-) (33 ± 20 mmol O2 (-) cell(-1)), relative to control. Altered plasma amino acid and acylcarnitine concentrations with protein-leucine feeding might partly explain the acute post-exercise reduction in neutrophil function and increased exercise-stimulated neutrophil oxidative burst on day 6, which could impact neutrophil-dependent processes during recovery from intense training.
- Published
- 2013
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41. Fructose-maltodextrin ratio governs exogenous and other CHO oxidation and performance.
- Author
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O'Brien WJ, Stannard SR, Clarke JA, and Rowlands DS
- Subjects
- Adult, Cross-Over Studies, Double-Blind Method, Fructose pharmacokinetics, Glucose metabolism, Humans, Male, Muscle Fatigue, Myalgia, Nausea etiology, Oxidation-Reduction, Physical Exertion, Polysaccharides pharmacokinetics, Taste, Athletic Performance physiology, Bicycling physiology, Fructose administration & dosage, Fructose metabolism, Polysaccharides administration & dosage, Polysaccharides metabolism
- Abstract
Introduction: Fructose coingested with glucose in carbohydrate (CHO) drinks increases exogenous-CHO oxidation, gut comfort, and physical performance., Purpose: This study aimed to determine the effect of different fructose-maltodextrin-glucose ratios on CHO oxidation and fluid absorption while controlling for osmolality and caloricity., Methods: In a crossover design, 12 male cyclists rode 2 h at 57% peak power then performed 10 sprints while ingesting artificially sweetened water or three equiosmotic 11.25% CHO-salt drinks at 200 mL·15 min, comprising weighed fructose and maltodextrin-glucose in ratios of 0.5:1 (0.5 ratio), 0.8:1 (0.8 ratio), and 1.25:1 (1.25 ratio). Fluid absorption was traced with D2O, whereas C-fructose and C-maltodextrin-glucose permitted fructose and glucose oxidation rate evaluation., Results: The mean exogenous-fructose and exogenous-glucose oxidation rates were 0.27, 0.39, and 0.46 g·min and 0.65, 0.71, and 0.58 g·min in 0.5, 0.8, and 1.25 ratio drinks, representing mean oxidation efficiencies of 54%, 59%, and 55% and 65%, 85%, and 86% for fructose and glucose, respectively. With the 0.8 ratio drink, total exogenous-CHO oxidation rate was 18% (90% confidence interval, ±5%) and 5.2% (±4.6%) higher relative to 0.5 and 1.25 ratios, respectively, whereas respective differences in total exogenous-CHO oxidation efficiency were 17% (±5%) and 5.3% (±4.8%), associated with 8.6% and 7.8% (±4.2%) higher fructose oxidation efficiency. The effects of CHO ratio on water absorption were inconclusive. Mean sprint power with the 0.8 ratio drink was moderately higher than that with the 0.5 ratio (2.9%; 99% confidence interval, ±2.8%) and 1.25 ratio (3.1%; ±2.7%) drinks, with total- and endogenous-CHO oxidation rate, abdominal cramps, and drink sweetness qualifying as explanatory mechanisms., Conclusions: Enhanced high-intensity endurance performance with a 0.8 ratio fructose-maltodextrin-glucose drink is characterized by higher exogenous-CHO oxidation efficiency and reduced endogenous-CHO oxidation. The gut-hepatic or other physiological site responsible requires further research.
- Published
- 2013
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42. Impact of autologous blood injections in treatment of mid-portion Achilles tendinopathy: double blind randomised controlled trial.
- Author
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Bell KJ, Fulcher ML, Rowlands DS, and Kerse N
- Subjects
- Adult, Double-Blind Method, Female, Humans, Male, Middle Aged, New Zealand, Patient Compliance, Prospective Studies, Treatment Outcome, Achilles Tendon pathology, Blood Transfusion, Autologous methods, Pain Management methods, Resistance Training methods, Tendinopathy therapy
- Abstract
Objective: To assess the effectiveness of two peritendinous autologous blood injections in addition to a standardised eccentric calf strengthening programme in improving pain and function in patients with mid-portion Achilles tendinopathy., Design: Single centre, participant and single assessor blinded, parallel group, randomised, controlled trial., Setting: Single sports medicine clinic in New Zealand., Participants: 53 adults (mean age 49, 53% men) with symptoms of unilateral mid-portion Achilles tendinopathy for at least three months. Participants were excluded if they had a history of previous Achilles tendon rupture or surgery or had undergone previous adjuvant treatments such as injectable therapies, glyceryl trinitrate patches, or extracorporeal shockwave therapy., Interventions: All participants underwent two unguided peritendinous injections one month apart with a standardised protocol. The treatment group had 3 mL of their own whole blood injected while the control group had no substance injected (needling only). Participants in both groups carried out a standardised and monitored 12 week eccentric calf training programme. Follow-up was at one, two, three and six months., Main Outcome Measures: The primary outcome measure was the change in symptoms and function from baseline to six months with the Victorian Institute of Sport Assessment-Achilles (VISA-A) score. Secondary outcomes were the participant's perceived rehabilitation and their ability to return to sport., Results: 26 participants were randomly assigned to the treatment group and 27 to the control group. In total, 50 (94%) completed the six month study, with 25 in each group. Clear and clinically worthwhile improvements in the VISA-A score were evident at six months in both the treatment (change in score 18.7, 95% confidence interval 12.3 to 25.1) and control (19.9, 13.6 to 26.2) groups. The overall effect of treatment was not significant (P=0.689) and the 95% confidence intervals at all points precluded clinically meaningful benefit or harm. There was no significant difference between groups in secondary outcomes or in the levels of compliance with the eccentric calf strengthening programme. No adverse events were reported., Conclusion: The administration of two unguided peritendinous autologous blood injections one month apart, in addition to a standardised eccentric training programme, provides no additional benefit in the treatment of mid-portion Achilles tendinopathy., Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12610000824066, WHO U1111-1117-2641.
- Published
- 2013
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43. Accurate Quantitation of Dystrophin Protein in Human Skeletal Muscle Using Mass Spectrometry.
- Author
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Brown KJ, Marathi R, Fiorillo AA, Ciccimaro EF, Sharma S, Rowlands DS, Rayavarapu S, Nagaraju K, Hoffman EP, and Hathout Y
- Abstract
Quantitation of human dystrophin protein in muscle biopsies is a clinically relevant endpoint for both diagnosis and response to dystrophin-replacement therapies for dystrophinopathies. A robust and accurate assay would enable the use of dystrophin as a surrogate biomarker, particularly in exploratory Phase 2 trials. Currently available methods to quantitate dystrophin rely on immunoblot or immunohistochemistry methods that are not considered robust. Here we present a mass spectrometry based approach to accurately quantitate dystrophin protein in a total protein extract from human muscle biopsies. Our approach uses a combination of stable isotope labeled dystrophin as a spike-in standard, gel electrophoresis and high precision mass spectrometry to detect and quantitate multiple peptides of dystrophin within a complex protein mixture. The method was found highly reproducible and linear over a wide dynamic range, detecting as low as 5% of dystrophin relative to the normal amount in healthy individuals.
- Published
- 2012
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44. L-Arginine but not L-glutamine likely increases exogenous carbohydrate oxidation during endurance exercise.
- Author
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Rowlands DS, Clarke J, Green JG, and Shi X
- Subjects
- Administration, Oral, Adult, Carbohydrate Metabolism drug effects, Cross-Over Studies, Double-Blind Method, Humans, Male, Oxidation-Reduction drug effects, Physical Endurance drug effects, Arginine administration & dosage, Bicycling physiology, Carbohydrate Metabolism physiology, Dietary Carbohydrates metabolism, Glutamine administration & dosage, Physical Endurance physiology
- Abstract
The addition of L-arginine or L-glutamine to glucose-electrolyte solutions can increase intestinal water, glucose, and sodium absorption in rats and humans. We evaluated the utility of L-arginine and L-glutamine in energy-rehydration beverages through assessment of exogenous glucose oxidation and perceptions of exertion and gastrointestinal distress during endurance exercise. Eight cyclists rode 150 min at 50% of peak power on four occasions while ingesting solutions at a rate of 150 mL 15 min(-1) that contained (13)C-enriched glucose (266 mmol L(-1)) and sodium citrate ([Na(+)] 60 mmol L(-1)), and either: 4.25 mmol L(-1) L-arginine or 45 mmol L(-1) L-glutamine, and as controls glucose only or no glucose. Relative to glucose only, L-arginine invoked a likely 12% increase in exogenous glucose oxidation (90% confidence limits: ± 8%); however, the effect of L-glutamine was possibly trivial (4.5 ± 7.3%). L-Arginine also led to very likely small reductions in endogenous fat oxidation rate relative to glucose (12 ± 4%) and L-glutamine (14 ± 4%), and relative to no glucose, likely reductions in exercise oxygen consumption (2.6 ± 1.5%) and plasma lactate concentration (0.20 ± 0.16 mmol L(-1)). Effects on endogenous and total carbohydrate oxidation were inconsequential. Compared with glucose only, L-arginine and L-glutamine caused likely small-moderate effect size increases in perceptions of stomach fullness, abdominal cramp, exertion, and muscle tiredness during exercise. Addition of L-arginine to a glucose and electrolyte solution increases the oxidation of exogenous glucose and decreases the oxygen cost of exercise, although the mechanisms responsible and impact on endurance performance require further investigation. However, L-arginine also increases subjective feelings of gastrointestinal distress, which may attenuate its other benefits.
- Published
- 2012
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45. Composite versus single transportable carbohydrate solution enhances race and laboratory cycling performance.
- Author
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Rowlands DS, Swift M, Ros M, and Green JG
- Subjects
- Adult, Biological Transport, Colic etiology, Colic physiopathology, Cross-Over Studies, Diarrhea etiology, Diarrhea physiopathology, Dietary Carbohydrates adverse effects, Dose-Response Relationship, Drug, Electrolytes pharmacology, Energy Metabolism drug effects, Female, Fructose adverse effects, Humans, Male, Muscle Fatigue drug effects, Nausea etiology, Nausea physiopathology, Polysaccharides adverse effects, Athletic Performance, Bicycling, Dietary Carbohydrates pharmacology, Fructose pharmacology, Physical Endurance drug effects, Polysaccharides pharmacology
- Abstract
When ingested at high rates (1.8-2.4 g·min(-1)) in concentrated solutions, carbohydrates absorbed by multiple (e.g., fructose and glucose) vs. single intestinal transporters can increase exogenous carbohydrate oxidation and endurance performance, but their effect when ingested at lower, more realistic, rates during intermittent high-intensity endurance competition and trials is unknown. Trained cyclists participated in two independent randomized crossover investigations comprising mountain-bike races (average 141 min; n = 10) and laboratory trials (94-min high-intensity intervals followed by 10 maximal sprints; n = 16). Solutions ingested during exercise contained electrolytes and fructose + maltodextrin or glucose + maltodextrin in 1:2 ratio ingested, on average, at 1.2 g carbohydrate·kg(-1)·h(-1). Exertion, muscle fatigue, and gastrointestinal discomfort were recorded. Data were analysed using mixed models with gastrointestinal discomfort as a mechanism covariate; inferences were made against substantiveness thresholds (1.2% for performance) and standardized difference. The fructose-maltodextrin solution substantially reduced race time (-1.8%; 90% confidence interval = ±1.8%) and abdominal cramps (-8.1 on a 0-100 scale; ±6.6). After accounting for gastrointestinal discomfort, the effect of the fructose-maltodextrin solution on lap time was reduced (-1.1%; ±2.4%), suggesting that gastrointestinal discomfort explained part of the effect of fructose-maltodextrin on performance. In the laboratory, mean sprint power was enhanced (1.4%; ±0.8%) with fructose-maltodextrin, but the effect on peak power was unclear (0.7%; ±1.5%). Adjusting out gastrointestinal discomfort augmented the fructose-maltodextrin effect on mean (2.6%; ±1.9%) and peak (2.5%; ±3.0%) power. Ingestion of multiple transportable vs. single transportable carbohydrates enhanced mountain-bike race and high-intensity laboratory cycling performance, with inconsistent but not irreconcilable effects of gut discomfort as a possible mediating mechanism.
- Published
- 2012
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46. Oxidative stress, inflammation, and muscle soreness in an 894-km relay trail run.
- Author
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Rowlands DS, Pearce E, Aboud A, Gillen JB, Gibala MJ, Donato S, Waddington JM, Green JG, and Tarnopolsky MA
- Subjects
- Adult, Creatine Kinase blood, Dinoprost analogs & derivatives, Dinoprost urine, Female, Humans, Interleukin-6 blood, Lipid Peroxidation, Male, Antioxidants metabolism, Exercise physiology, Inflammation metabolism, Muscle, Skeletal metabolism, Oxidative Stress physiology, Pain metabolism, Running physiology
- Abstract
We describe the effects of multi-day relay trail running on muscle soreness and damage, and systemic immune, inflammatory, and oxidative responses. 16 male and 4 female athletes ran 894 km in 47 stages over 95 h, with mean (SD) 6.4 (1.0) stages per athlete and 19.0 (1.7) km per stage. We observed post-pre run increases in serum creatine kinase (qualified effect size extremely large, p = 0.002), IL-6 (extremely large, p < 0.001), urinary 8-isoprostane/creatinine (extremely large, p = 0.04), TNF-α (large, p = 0.002), leukocyte count (very large, p < 0.0001) and neutrophil fraction (very large, p < 0.001); and reductions in hemoglobin (moderate, p < 0.001), hematocrit (moderate, p < 0.001), and lymphocyte fraction (trivial, p < 0.001). An increase in ORAC total antioxidant capacity (TAC, small, p = 0.3) and decrease in urinary 8-OHdG/creatinine (small, p = 0.1) were not statistically significant. During the run, muscle soreness was most frequent in the quadriceps. The threshold for muscle pain (pain-pressure algometry) in the vastus lateralis and gastrocnemius was lower post-run (small, p = 0.04 and 0.03). Average running speed was correlated with algometer pain and leukocyte count (large, r = 0.52), and TAC was correlated with IL-6 (very large, r = 0.76) and 8-isoprostane/creatinine (very large, r = -0.72). Multi-day stage-racing increases inflammation, lipid peroxidation, muscle damage and soreness without oxidative DNA damage. High TAC is associated with reduced exercise-induced lipid peroxidation, but is not related to immune response or muscle damage.
- Published
- 2012
- Full Text
- View/download PDF
47. No effect of protein coingestion on exogenous glucose oxidation during exercise.
- Author
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Rowlands DS and Wadsworth DP
- Subjects
- Adult, Athletic Performance physiology, Athletic Performance psychology, Blood Glucose metabolism, Blood Glucose physiology, Cross-Over Studies, Dietary Carbohydrates administration & dosage, Dietary Carbohydrates metabolism, Glucose administration & dosage, Glucose physiology, Humans, Lactic Acid blood, Male, Oxygen Consumption physiology, Physical Endurance physiology, Bicycling physiology, Dietary Proteins administration & dosage, Glucose metabolism
- Abstract
Purpose: We examined the hypothesis that protein coingestion with glucose during endurance exercise increases exogenous glucose oxidation rate and gut comfort and lowers perceived exertion., Methods: In a randomized crossover design, eight male cyclists rode 150 min at 50% of peak power on three occasions while ingesting solutions containing the following: 8% ¹³C-enriched glucose and 2% milk protein concentrate (protein-glucose), glucose only (glucose), or noncaloric placebo (water). All solutions contained sodium citrate ([⁺Na] 60 mmol·L⁻¹) and flavor and were ingested at 150 mL·15 min⁻¹. The exogenous carbohydrate oxidation rate was determined using stable isotope method and indirect calorimetry., Results: Protein coingestion had no effect on the exogenous glucose oxidation rate but increased endogenous carbohydrate oxidation rate (16%; 90% confidence limits ±7%), relative to glucose. Total carbohydrate and fat oxidation rates were increased (25%; ±6%) and decreased (17%; ±4%), respectively, by protein coingestion relative to water, but the effect relative to glucose was trivial. The plasma glucose concentration relative to glucose (mean ± SD; 6.1 ± 0.8 mmol·L⁻¹) was 5.8% (±3%) lower with protein coingestion; there were no clear differences in glucose concentration for the remaining comparisons or for lactate concentration. Perceived exertion was not altered by protein coingestion; however, there was a small decrease in nausea with the protein-glucose solution relative to water (-0.14 ± 0.08 U); other protein-affected comparisons were without note., Conclusions: Adding protein to a glucose-sodium solution ingested during exercise had neutral effect on exogenous carbohydrate oxidation and perception and little effect on metabolic measures associated with endurance performance. We conclude that previously reported effects of protein coingestion on endurance capacity were unlikely due to increased exogenous carbohydrate provision.
- Published
- 2012
- Full Text
- View/download PDF
48. Statistical perspectives: all together NOT.
- Author
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Hopkins WG, Batterham AM, Impellizzeri FM, Pyne DB, and Rowlands DS
- Subjects
- Biostatistics, Periodicals as Topic, Biomedical Research statistics & numerical data, Data Interpretation, Statistical
- Published
- 2012
- Full Text
- View/download PDF
49. A protein-leucine supplement increases branched-chain amino acid and nitrogen turnover but not performance.
- Author
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Nelson AR, Phillips SM, Stellingwerff T, Rezzi S, Bruce SJ, Breton I, Thorimbert A, Guy PA, Clarke J, Broadbent S, and Rowlands DS
- Subjects
- Adult, Amino Acids, Branched-Chain blood, Amino Acids, Branched-Chain urine, Aminoisobutyric Acids urine, Creatine Kinase blood, Cross-Over Studies, Dietary Carbohydrates administration & dosage, Dietary Carbohydrates metabolism, Dietary Proteins metabolism, Double-Blind Method, Humans, Leucine metabolism, Leucine urine, Male, Middle Aged, Muscle Strength drug effects, Muscle Strength physiology, Muscle, Skeletal drug effects, Muscle, Skeletal metabolism, Muscle, Skeletal physiology, Oxygen Consumption physiology, Running physiology, Amino Acids, Branched-Chain metabolism, Athletic Performance physiology, Dietary Proteins administration & dosage, Dietary Supplements, Leucine administration & dosage, Nitrogen metabolism
- Abstract
Purpose: This study aimed to determine the effect of postexercise protein-leucine coingestion with CHO-lipid on subsequent high-intensity endurance performance and to investigate candidate mechanisms using stable isotope methods and metabolomics., Methods: In this double-blind, randomized, crossover study, 12 male cyclists ingested a leucine/protein/CHO/fat supplement (LEUPRO 7.5/20/89/22 g · h(-1), respectively) or isocaloric CHO/fat control (119/22 g · h(-1)) 1-3 h after exercise during a 6-d training block (intense intervals, recovery, repeated-sprint performance rides). Daily protein intake was clamped at 1.9 g · kg(-1) · d(-1) (LEUPRO) and 1.5 g · kg(-1) · d(-1) (control). Stable isotope infusions (1-(13)C-leucine and 6,6-(2)H2-glucose), mass spectrometry-based metabolomics, and nitrogen balance methods were used to determine the effects of LEUPRO on whole-body branched-chain amino acid (BCAA) and glucose metabolism and protein turnover., Results: After exercise, LEUPRO increased BCAA levels in plasma (2.6-fold; 90% confidence limits = ×/÷ 1.1) and urine (2.8-fold; ×/÷ 1.2) and increased products of BCAA metabolism plasma acylcarnitine C5 (3.0-fold; ×/÷ 0.9) and urinary leucine (3.6-fold; ×/÷ 1.3) and β-aminoisobutyrate (3.4-fold; ×/÷ 1.4), indicating that ingesting ~10 g leucine per hour during recovery exceeds the capacity to metabolize BCAA. Furthermore, LEUPRO increased leucine oxidation (5.6-fold; ×/÷ 1.1) and nonoxidative disposal (4.8-fold; ×/÷ 1.1) and left leucine balance positive relative to control. With the exception of day 1 (LEUPRO = 17 ± 20 mg N · kg(-1), control = -90 ± 44 mg N · kg(-1)), subsequent (days 2-5) nitrogen balance was positive for both conditions (LEUPRO = 130 ± 110 mg N · kg(-1), control = 111 ± 86 mg N · kg(-1)). Compared with control feeding, LEUPRO lowered the serum creatine kinase concentration by 21%-25% (90% confidence limits = ± 14%), but the effect on sprint power was trivial (day 4 = 0.4% ± 1.0%, day 6 = -0.3% ± 1.0%)., Conclusions: Postexercise protein-leucine supplementation saturates BCAA metabolism and attenuates tissue damage, but effects on subsequent intense endurance performance may be inconsequential under conditions of positive daily nitrogen balance.
- Published
- 2012
- Full Text
- View/download PDF
50. Exercise intervention in New Zealand Polynesian peoples with type 2 diabetes: Cultural considerations and clinical trial recommendations.
- Author
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Sukala WR, Page RA, Rowlands DS, Lys I, Krebs JD, Leikis MJ, and Cheema BS
- Abstract
The Maori and Pacific Islands peoples of New Zealand suffer a greater burden of type 2 diabetes mellitus (T2DM) and associated comorbidities than their European counterparts. Empirical evidence supports the clinical application of aerobic and resistance training for effective diabetes management and potential remission, but few studies have investigated the effectiveness of these interventions in specific ethnic cohorts. We recently conducted the first trial to investigate the effect of prescribed exercise training in Polynesian people with T2DM. This article presents the cultural considerations undertaken to successfully implement the study. The research procedures were accepted and approved by cultural liaisons and potential participants. The approved methodology involved a trial evaluating and comparing the effects of two, 16-week exercise regimens (i.e. aerobic training and resistance training) on glycosylated haemoglobin (HbA1c), related diabetes markers (i.e. insulin resistance, blood lipids, relevant cytokines and anthropometric and hemodynamic indices) and health-related quality of life. Future exercise-related research or implementation strategies in this cohort should focus on cultural awareness and techniques to enhance participation and compliance. Our approach to cultural consultation could be considered by researchers undertaking trials in this and other ethnic populations suffering an extreme burden of T2DM, including indigenous Australians and Americans.
- Published
- 2012
- Full Text
- View/download PDF
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