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OBJECTIVE: To assess the effect of short-term testosterone supplementation on health-related quality of life in elderly males. METHOD: As part of a double-blind, placebo-controlled study, healthy males > or = 65-year-old were randomised to receive a total of four doses of 200 mg testosterone enanthanate (n = 14) or placebo (n = 8) intramuscularly every 2 weeks. Health-related quality of life (HRQOL) was assessed using the Short Form 36-item (SF-36) and Psychological General Well-Being (PGWB) scales, at baseline, week 8 and during therapy withdrawal, 6 weeks after the last dose. RESULTS: The baseline SF-36 scores were similar between the groups in seven domains; only vitality was significantly lower in the placebo group (T: 80.4, P: 65.6; P = 0.007). After the 8-week treatment period and withdrawal phase, SF-36 scores were not significantly different between the groups. The PGWB scores at baseline, on treatment and off treatment were not significantly different between the groups. Moreover, the SF-36 and PGWB scores within each group did not change significantly over time. CONCLUSION: This pilot study suggests that intramuscular testosterone, administered at a dose of 200 mg every 2 weeks, does not affect the HRQOL of elderly males. [ABSTRACT FROM AUTHOR]

Exercise training is recommended for pulmonary hypertension (PH). Post hoc analysis of the PH and Home-Based (PHAHB) trial stratified patients into two groups based on median diffusing capacity of the lungs for carbon monoxide (DLCO). Patients with higher DLCO had a greater improvement in physical activity performance in response to exercise training, compared to those with lower DLCO. DLCO may be an important consideration in prescribing exercise in PH., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Pulmonary Circulation published by John Wiley & Sons Ltd on behalf of Pulmonary Vascular Research Institute.)

Background: Pulmonary hypertension (PH) is a heterogeneous condition, associated with a high symptom burden and a substantial loss of exercise capacity. Despite prior safety concerns regarding physical exertion, exercise training as a supportive therapy is now recommended for PH patients. Currently, most programmes are hospital-based, which limits accessibility. There is a need to provide alternative approaches for physical activity engagement for PH patients. The aim of this research was to develop, implement and evaluate the safety, feasibility and effectiveness of home-based physical activity intervention for PH., Methods: An entirely remotely delivered home-based physical activity intervention underpinned by behaviour change theory and informed by end-users, was assessed using a single-arm feasibility study design. Participants (n=19; 80% female) with a mean±sd age of 49.9±15.9 years with a diagnosis of PH undertook a 10-week, home-based physical activity intervention with induction training, support materials, telecommunication support, health coaching, exercise training and assessments, all remotely delivered. Training involved respiratory training along with a combination of aerobic and resistance exercises., Results: The intervention was deemed safe as no adverse events were reported. A high level of feasibility was demonstrated as the protocol was implemented as intended, sustained a high level of engagement and adherence and was well accepted by participants in terms of enjoyment and utility. There was a significant improvement in functional capacity, physical activity, exercise self-efficacy and quality of life, between baseline and post-training., Conclusion: The study demonstrates that an entirely remotely delivered home-based physical activity programme is safe, feasible and effective in improving functional capacity, physical activity and quality of life in PH patients., Competing Interests: Conflict of interest: B. Kehoe's institution has received grant funding for the submitted research from Actelion Pharmaceuticals. B. Kehoe has received grant funding from the National Cancer Control Programme and Irish Research Council, outside the work submitted. Conflict of interest: S. Gaine's institution has received grant funding for the submitted research from Actelion Pharmaceuticals. S. Gaine has received honoraria and speaker's fees from MSD and Janssen Pharmaceuticals, outside the submitted work; received travel support from MSD and Janssen Pharmaceuticals, outside the submitted work; participated in a data safety monitoring board for United Therapeutics and Janssen Pharmaceuticals; and has received consulting fees from or Altavant, Gossamer Bio, Janssen and MSD outside the submitted work. Conflict of interest: B. McCullagh has received honoraria, speaker's fees and travel support from Janssen Pharmaceuticals, outside the submitted work. Conflict of interest: N.M. Moyna's institution has received grant funding for the submitted research from Actelion Pharmaceuticals. N.M. Moyna has received grants from Enterprise Ireland and Health Service Executive, outside the submitted work; and received consulting fees from Irish Health Life, outside of the submitted work. Conflict of interest: All other authors have nothing to disclose., (Copyright ©The authors 2024.)

The purpose of this study was to compare the activity profile of elite Gaelic football referees (GFR) between the National Football League (NFL) and the All-Ireland Championship (AIC), and across the four divisions of the NFL and three phases of the AIC. Match activity data was collected during 125 NFL and 201 AIC games using 10-Hz global positioning system technology from 41 elite GFR. Game duration, total distance, very low-speed movement (<0.70 m·s -1 ), walking (≥0.70-1.65 m·s -1 ), low-speed running (≥1.66-3.27 m·s -1 ), moderate-speed running (≥3.28-4.86 m·s -1 ), high-speed running (≥4.87-6.48 m·s -1 ), very high-speed running (≥6.49 m·s -1 ) distance, and peak running speed were compared between competitions. Games in the AIC were longer than in the NFL (ES = 0.59) but the total distance was similar between the NFL (119.6 ± 9.5 m·min -1 ) and AIC (122.6 ± 8.4 m·min -1 , ES = 0.11). No other differences were found between the NFL and AIC or across the four divisions of the NFL and three phases of the AIC, except for a higher peak running speed during the All-Ireland Series (6.93 ± 0.52 m·s -1 ) than the All-Ireland Qualifiers (6.65 ± 0.46 m·s -1 , ES = 0.35). This information can be used to design specific conditioning programmes to ensure optimal physical development of GFR at all competitive levels.

The purpose of this study was to examine the activity profile of elite Gaelic football referees (GFR) and to examine temporal changes between the first and second half and across the four quarters. Global positioning systems technology (10-Hz) was used to collect activity data during 202 competitive games from 23 elite GFR. Relative distance, peak running speed and relative distance covered in six movement categories [very low-speed movement (VLSM) (<0.70 m·s -1 ), walking (≥0.70-1.65 m·s -1 ), low-speed running (LSR) (≥1.66-3.27 m·s -1 ), moderate-speed running (MSR) (≥3.28-4.86 m·s -1 ), high-speed running (HSR) (≥4.87-6.48 m·s -1 ), very high-speed running (VHSR) (≥6.49 m·s -1 )] were examined during the full game, first and second half, and across the four quarters. The relative distance covered was 122.6 ± 8.4 m·min -1 , with 13.1 ± 4.9 m·min -1 of HSR and VHSR. The peak running speed was 6.75 ± 0.49 m·s -1 . The relative (ES=0.60), MSR (ES=0.50) and HSR (ES=0.14) distance was higher in the first half than the second half. A higher relative (ES=0.62-0.91) and HSR (ES=0.51-0.61) distance was found in the first quarter than any other period. No differences in HSR distance were found between the second, third and fourth quarters (ES=0.04-0.10). This study provides, for the first time, a detailed insight into the activity profile of elite GFR during competitive games and demonstrates the demanding, intermittent nature of elite refereeing in Gaelic football. This information may be used as a framework for coaches to design training programmes specific to GFR.

Objective: Physical activity (PA) is an established adjunct therapy for pulmonary hypertension (PH) patients to mitigate PH symptoms and improve quality of life. However, PA engagement within this population remains low. This study investigated PH patients' knowledge of PA, recalled advice, exercise preferences and PA support needs., Methods: Semi-structured interviews were conducted with 19 adults (mean age 50 years; SD ±12 years) diagnosed with PH, living in Ireland. Interview scripts were digitally recorded and transcribed verbatim. Thematic analysis was used to analyse the data., Results: Four key themes were identified: Lack of PA knowledge; exercise setting preference; accountability and monitoring; and clinician delivered PA information and guidance., Conclusion: This study found that PH clinicians provide suboptimal PA advice, yet patients desired clinician-delivered PA guidance. Home-based exercise was preferred with monitoring and external accountability deemed as important to facilitate sustained engagement., Practice Implications: PH clinicians are well positioned to play a critical role in assisting and empowering PH patients to engage in PA. Providing training and education to PH clinicians regarding exercise prescription may be beneficial. Further research is needed to evaluate the feasibility and efficacy of home-based exercise interventions to improve quality of life and physical activity in PH., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 McCormack et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Ground based research modalities of microgravity have been proposed as innovative methods to investigate the aetiology of chronic age-related conditions such as cardiovascular disease. Dry Immersion (DI), has been effectively used to interrogate the sequelae of physical inactivity (PI) and microgravity on multiple physiological systems. Herein we look at the causa et effectus of 3-day DI on platelet phenotype, and correlate with both miRomic and circulating biomarker expression. The miRomic profile of platelets is reflective of phenotype, which itself is sensitive and malleable to the exposome, undergoing responsive transitions in order to fulfil platelets role in thrombosis and haemostasis. Heterogeneous platelet subpopulations circulate at any given time, with varying degrees of sensitivity to activation. Employing a DI model, we investigate the effect of acute PI on platelet function in 12 healthy males. 3-day DI resulted in a significant increase in platelet count, plateletcrit, platelet adhesion, aggregation, and a modest elevation of platelet reactivity index (PRI). We identified 15 protein biomarkers and 22 miRNA whose expression levels were altered after DI. A 3-day DI model of microgravity/physical inactivity induced a prothrombotic platelet phenotype with an unique platelet miRNA signature, increased platelet count and plateletcrit. This correlated with a unique circulating protein biomarker signature. Taken together, these findings highlight platelets as sensitive adaptive sentinels and functional biomarkers of epigenetic drift within the cardiovascular compartment., (© 2021. The Author(s).)

Pulmonary hypertension is a progressive cardiorespiratory disease that is characterized by considerable morbidity and mortality. While physical activity can improve symptoms and quality of life, engagement in this population is suboptimal. The aim of this study was to explore attitudes towards exercise and the dimensions that influence physical activity participation in individuals with pulmonary hypertension. Virtual, semi-structured interviews were conducted with individuals, with a formal diagnosis of pulmonary hypertension. Participants were recruited through the Pulmonary Hypertension Association of Ireland. Interviews were transcribed and analysed using thematic analysis. Nineteen patients were interviewed (n = 19). There was a female preponderance (n = 13) and the mean age was 50 ± 12 years. Three themes were identified and included fear, perceived value of exercise and environmental factors. Fear was the primary theme and included three sub-themes of fear of (i) over-exertion, (ii) physical damage and (iii) breathlessness. The perceived value of exercise encompassed two distinct sub-themes of perceived (i) exercise importance and (ii) benefits of exercise. Environmental factors included the terrain, weather conditions and location. Fear of overexertion, harm and dyspnoea strongly influenced attitudes to and engagement in physical activity. This study revealed heterogenous patient perspectives regarding the importance of physical activity and exercise. Future interventions that mitigate fear and promote the value of physical activity for individuals with pulmonary hypertension may have considerable benefits in promoting physical activity engagement. Such interventions require multidisciplinary involvement, including specialised pulmonary hypertension clinicians and exercise and behaviour change specialists., (© The Author(s) 2021.)

Purpose: While ideal for developing aerobic capacity, traditional endurance training (ET) is extremely time-consuming and may lack the specificity to maintain indices of speed and power in team sport athletes. In contrast, low-volume short-duration sprint interval training (SIT) has been shown to improve [Formula: see text]O 2 max to a similar extent as ET. However, to date, few studies have compared the effects of running-based SIT and ET, on aerobic capacity and indices of speed and power of trained team sport athletes., Methods: Club level male Gaelic football players were randomly assigned to SIT (n = 13; 26.5 ± 4.87 years) or ET (n = 12; 25.4 ± 2.58 years) groups. Participants trained 3 days week -1 for 6 weeks. [Formula: see text]O 2 max, RE, v[Formula: see text]O 2 max, blood lactate concentrations, Wingate test performance, running speed, jump performance and intermittent endurance performance (IEP) were measured at baseline and after 6 weeks., Results: An increase in [Formula: see text]O 2 max (p < 0.05), v[Formula: see text]O 2 max (p < 0.001) and IEP (p < 0.001) following 6 weeks of both SIT and ET was observed. Wingate mean power (p < 0.001), peak power (p < 0.001) and fatigue index (p < 0.005) were all significantly improved following training in both groups. Velocity at LT was significantly higher and performance in the 20-m running speed and VJ tests were significantly reduced post training in the ET group (all p < 0.005)., Conclusion: Despite the large difference in total training time, a running-based protocol of SIT is a time efficient training method for improving aerobic capacity and IEP while maintaining indices of lower body power and running speed in team-sport players.

Background: Physical activity (PA) is a well-documented and accepted adjunct therapy for the maintenance and improvement of long-term health in cystic fibrosis (CF). Although the benefits of PA for CF populations are well-established, adherence to PA programmes within this population remains low. This study aimed to investigate the factors that influence engagement in physical activity, and to explore exercise preferences, among adults with cystic fibrosis (CF)., Methods: Semi-structured telephone interviews were conducted. Participants were twenty-one adults (mean age 35 years, SD ± 8) with an established diagnosis of CF, living in Ireland. Interview scripts were digitally recorded and transcribed verbatim. Thematic analysis was used to analyse the data., Results: Four main themes emerged: barriers, motives, value of exercise-related outcomes, and exercise preferences. The main barriers included: low energy levels, time, the weather, and exercise-related confidence. Enjoyment and perceived competence underpinned autonomous motivation. Participants who self-identified as being regularly active valued personally identified exercise-related outcomes such as, accomplishment and affect regulation. Participants indicated a preference for home-based physical activity programs compared to gym- or facility-based programs., Conclusion: Interventions aimed at promoting physical activity among adults with CF should involve programs that foster autonomous motivation, enjoyable activities, personally identified outcomes, competence and that can be conducted from the home environment., Clinical Implications: To increase physical activity participation among adults with CF, interventions that can be conducted from the home environment, that pay attention to the patients' personally-valued exercise outcomes may be required.

Background/objective: Measures of oxygen uptake efficiency (OUE) have been used to evaluate cardiorespiratory fitness (CRF) in adolescents unable to perform maximal exercise. The oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP) have been proposed as surrogates for maximal oxygen consumption (V̇O 2max ). We assessed the validity of the OUES and OUEP as predictors of V̇O 2max in healthy male adolescents., Methods: Sixty-three healthy male adolescents aged 15.40 ± 0.34 years underwent an incremental treadmill test to determine V̇O 2max , OUES and OUEP. OUE throughout the test was assessed by dividing each V̇O 2 value by the corresponding minute ventilation (V̇ E ) value. OUEP was determined as the 90 s average highest consecutive values for OUE. OUES was determined using data up to the ventilatory threshold (VT) by calculating the slope of the linear relation between V̇O 2 and the logarithm of V̇ E ., Results: Limits of agreement for V̇O 2max predicted by OUES (±13.3 mL kg -1. min -1 ) and OUEP (±16.7 mL kg -1. min -1 ) relative to V̇O 2max were wide and a magnitude bias was found for OUES and OUEP as predictors of V̇O 2max (p < 0.001)., Conclusion: The OUES and OUEP do not accurately predict V̇O 2max in male adolescents and should not replace V̇O 2max when assessing CRF in this population., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2020 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd.)

Background: Physical activity (PA) is a well-established therapeutic modality for the maintenance and improvement of long-term health in cystic fibrosis (CF). Healthcare professionals (HCP) are considered credible and well-placed messengers for the delivery of PA advice. Limited research exists investigating the extent of PA prescription within CF care. This study aimed to identify Irish HCP i) knowledge and practice of, and ii) motivators and barriers to PA prescription, and iii) proposed strategies to optimize PA promotion and prescription in CF populations., Methods: HCP from six designated CF centres in Ireland and members of the national physiotherapy CF clinical interest group were invited to participate. Following an expression of interest, each HCP (n = 81) received an email containing the plain language statement and link to the online survey. 48 HCP (physiotherapists n = 24, other n = 24) completed the 30-item investigator-developed survey, which included multiple choice single answer, matrix style and open-ended questions., Results: Most HCP (81%) acknowledged that discussing PA with CF patients was part of their professional role. Almost all physiotherapists (95%) reported having sufficient knowledge regarding PA prescription, compared to 17% of other HCP. All physiotherapists reported discussing PA at every patient interaction, with 81% employing the current consensus guidelines, compared to 33 and 5% of other HCP, respectively. Among the most common barriers reported by HCP to recommending PA to their CF patients were; lack of motivation and compliance among patients to adhere to PA advice, limited availability of PA programmes to refer their patients to, limited time with patients during clinic visits and a lack of knowledge regarding PA prescription for CF care. Three-quarters of HCP reported a need to improve PA services for CF patients in Ireland., Conclusion: As people with CF are living longer, it is imperative that HCP are expanding their scope of practice to include discussions around PA at every patient visit. Formal educational opportunities in the form of continuing professional development programmes are warranted for CF HCP to optimize long-term patient management and outcomes. There is also a need to develop patient-centered and evidence-based PA programmes underpinned by theories of behaviour change to enhance motivation and compliance among CF patients.

Background: Burn injuries are a major cause of morbidity and mortality worldwide. Despite advances in therapeutic strategies for the management of patients with severe burns, the sequelae are pathophysiologically profound, up to the systemic and metabolic levels. Management of patients with a severe burn injury is a long-term, complex process, with treatment dependent on the degree and location of the burn and total body surface area (TBSA) affected. In adverse conditions with limited resources, efficient triage, stabilisation, and rapid transfer to a specialised intensive care burn centre is necessary to provide optimal outcomes. This initial lag time and the form of primary treatment initiated, from injury to specialist care, is crucial for the burn patient. This study aims to investigate the efficacy of a novel visco-elastic burn dressing with a proprietary bio-stimulatory marine mineral complex (MXC) as a primary care treatment to initiate a healthy healing process prior to specialist care., Methods: A new versatile emergency burn dressing saturated in a >90% translucent water-based, sterile, oil-free gel and carrying a unique bio-stimulatory marine mineral complex (MXC) was developed. This dressing was tested using LabSkin as a burn model platform. LabSkin a novel cellular 3D-dermal organotypic full thickness human skin equivalent, incorporating fully-differentiated dermal and epidermal components that functionally models skin. Cell and molecular analysis was carried out by in vitro Real-Time Cellular Analysis (RTCA), thermal analysis, and focused transcriptomic array profiling for quantitative gene expression analysis, interrogating both wound healing and fibrosis/scarring molecular pathways. In vivo analysis was also performed to assess the bio-mechanical and physiological effects of this novel dressing on human skin., Results: This hybrid emergency burn dressing (EBD) with MXC was hypoallergenic, and improved the barrier function of skin resulting in increased hydration up to 24 h. It was demonstrated to effectively initiate cooling upon application, limiting the continuous burn effect and preventing local tissue from damage and necrosis. xCELLigence RTCA® on primary human dermal cells (keratinocyte, fibroblast and micro-vascular endothelial) demonstrated improved cellular function with respect to tensegrity, migration, proliferation and cell-cell contact (barrier formation) [1]. Quantitative gene profiling supported the physiological and cellular function finding. A beneficial quid pro quo regulation of genes involved in wound healing and fibrosis formation was observed at 24 and 48 h time points., Conclusion: Utilisation of this EBD + MXC as a primary treatment is an effective and easily applicable treatment in cases of burn injury, proving both a cooling and hydrating environment for the wound. It regulates inflammation and promotes healing in preparation for specialised secondary burn wound management. Moreover, it promotes a healthy remodelling phenotype that may potentially mitigate scarring. Based on our findings, this EBD + MXC is ideal for use in all pre-hospital, pre-surgical and resource limited settings., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The SwEatch platform, a wearable sensor for sampling and measuring the concentration of electrolytes in human sweat in real time, has been improved in order to allow the sensing of two analytes. The solid contact ion-sensitive electrodes (ISEs) for the detection of Na + and K + have been developed in two alternative formulations, containing either poly(3,4-ethylenedioxythiophene) (PEDOT) or poly(3-octylthiophene-2,5-diyl) (POT) as a conductive polymer transducing component. The solution-processable POT formulation simplifies the fabrication process, and sensor to sensor reproducibility has been improved via partial automation using an Opentron® automated pipetting robot. The resulting electrodes showed good sensitivity (52.4 ± 6.3 mV/decade (PEDOT) and 56.4 ± 2.2 mV/decade (POT) for Na + ISEs, and 45.7 ± 7.4 mV/decade (PEDOT) and 54.3 ± 1.5 mV/decade (POT) for K + ) and excellent selectivity towards potential interferents present in human sweat (H + , Na + , K + , Mg 2+ , Ca 2+ ). The 3D printed SwEatch platform has been redesigned to incorporate a double, mirrored fluidic unit which is capable of drawing sweat from the skin through passive capillary action and bring it in contact with two independent electrodes. The potentiometric signal generated by the electrodes is measured by an integrated electronics board, digitised and transmitted via Bluetooth to a laptop. The results obtained from on-body trials on athletes during cycling show a relatively small increase in sodium (1.89 mM-2.97 mM) and potassium (3.31 mM-7.25 mM) concentrations during the exercise period of up to 90 min., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Exercise training provides benefits for individuals with cystic fibrosis; however, the optimal program is unclear. High-intensity interval training is safe and effective for improving 'functional capacity' in these individuals with peak rate of O 2 uptake typically referenced. The ability to adjust submaximal rate of oxygen uptake (V̇O 2 kinetics) might be more important for everyday function because maximal efforts are usually not undertaken. Moreover, the ability of high-intensity training to accelerate V̇O 2 kinetics for individuals with cystic fibrosis could be enhanced with O 2 supplementation during training., Methods: Nine individuals with cystic fibrosis completed incremental cycling to limit of tolerance followed by 8 weeks of high-intensity interval cycling (2 sessions per week x ~ 45 min per session) either with ( n  = 5; O2+) or without (AMB) oxygen supplementation (100%). Each session involved work intervals at 70% of peak work rate followed by 60 s of recovery at 35%. For progression, duration of work intervals was increased according to participant tolerance., Results: Both groups experienced a significant increase in work-interval duration over the course of the intervention (O2+, 1736 ± 141 v . 700 ± 154 s; AMB, 1463 ± 598 v . 953 ± 253 s; P  = 0.000); however, the increase experienced by O2+ was greater ( P  = 0.027). During low-intensity constant-work-rate cycling, the V̇O 2 mean response time was shortened post compared to pre training (O2+, 34 ± 11 v . 44 ± 9 s; AMB, 39 ± 14 v . 45 ± 17 s; P  = 0.000) while during high-intensity constant-work-rate cycling, time to exhaustion was increased (O2+, 1628 ± 163 v . 705 ± 133 s; AMB, 1073 ± 633 v . 690 ± 348 s; P  = 0.002) and blood [lactate] response was decreased (O2+, 4.5 ± 0.9 v . 6.3 ± 1.4 mmol . L - 1 ; AMB, 4.5 ± 0.6 v . 5.2 ± 1.4 mmol . L - 1 ; P  = 0.003). These positive adaptations were similar regardless of gas inspiration during training., Conclusion: Eight weeks of high-intensity interval training for patients with cystic fibrosis accelerated V̇O 2 kinetics and increased time to exhaustion. This provides some evidence that these patients may benefit from this type of exercise., Trial Registration: This study was retrospectively registered in the ISRTCN registry on 22/06/2019 (#ISRCTN13864650)., Competing Interests: Competing interestsFJD is editor of the Exercise Physiology section of BMC Sports, Science, Medicine and Rehabilitation., (© The Author(s). 2020.)

Kelly, DT, Tobin, C, Egan, B, Carren, AM, O'Connor, PL, McCaffrey, N, and Moyna, NM. Comparison of sprint interval and endurance training in team sport athletes. J Strength Cond Res 32(11): 3051-3058, 2018-High-volume endurance training (ET) has traditionally been used to improve aerobic capacity but is extremely time-consuming in contrast to low-volume short-duration sprint interval training (SIT) that improves maximal oxygen uptake (V[Combining Dot Above]O2max) to a similar extent. Few studies have compared the effects of SIT vs. ET using running-based protocols, or in team sport athletes. Club level male Gaelic football players were randomly assigned to SIT (n = 7; 21.6 ± 2.1 years) or ET (n = 8; 21.9 ± 3.5 years) for 6 sessions over 2 weeks. V[Combining Dot Above]O2max, muscle mitochondrial enzyme activity, running economy (RE), and high-intensity endurance capacity (HEC) were measured before and after training. An increase in V[Combining Dot Above]O2max (p ≤ 0.05) after 2 weeks of both SIT and ET was observed. Performance in HEC increased by 31.0 and 17.2% after SIT and ET, respectively (p ≤ 0.05). Running economy assessed at 8, 9, 10, and 11 km·h, lactate threshold and vV[Combining Dot Above]O2max were unchanged after both SIT and ET. Maximal activity of 3-β-hydroxylacyl coenzyme A dehydrogenase (β-HAD) was increased in response to both SIT and ET (p ≤ 0.05), whereas the maximal activity of citrate synthase remained unchanged after training (p = 0.07). A running-based protocol of SIT is a time-efficient training method for improving aerobic capacity and HEC, and maintaining indices of RE and lactate threshold in team sport athletes.

Cullen, BD, Roantree, M, McCarren, A, Kelly, DT, O'Connor, PL, Hughes, SM, Daly, PG, and Moyna1, NM. Physiological profile and activity pattern of minor Gaelic football players. J Strength Cond Res 31(7): 1811-1820, 2017-The purpose of this study was to evaluate the physiological profile and activity pattern in club- and county-level under-18 (U-18) Gaelic football players relative to playing position. Participants (n = 85) were analyzed during 17 official 15-a-side matches using global positioning system technology (SPI Pro X II; GPSports Systems, Canberra, Australia) and heart rate (HR) telemetry. During the second part of this study, 63 participants underwent an incremental treadmill test to assess their maximal oxygen uptake (V[Combining Dot Above]o2max) and peak HR (HRmax). Players covered a mean distance of 5,774 ± 737 m during a full 60-minute match. The mean %HRmax and %V[Combining Dot Above]O2max observed during the match play were 81.6 ± 4.3% and 70.1 ± 7.75%, respectively. The playing level had no effect on the distance covered, player movement patterns, or %HRmax observed during match play. Midfield players covered significantly greater distance than defenders (p = 0.033). Playing position had no effect on %HRmax or the frequency of sprinting or high-intensity running during match play. The frequency of jogging, cruise running, striding (p = 0.000), and walking (p = 0.003) was greater in the midfield position than in the forward position. Time had a significant effect (F(1,39) = 33.512, p-value = 0.000, and (Equation is included in full-text article.)= 0.462) on distance covered and %HRmax, both of which showed a reduction between playing periods. Gaelic football is predominantly characterized by low-to-moderate intensity activity interspersed with periods of high-intensity running. The information provided may be used as a framework for coaches in the design and prescription of training strategies. Positional specific training may be warranted given the comparatively greater demands observed in the midfield playing position. Replicating the demands of match play in training may reduce the decline in distance covered and %HRmax observed during the second half of match play.

Glucocorticoid receptor (NR3C1) polymorphisms associate with obesity, muscle strength, and cortisol sensitivity. We examined associations among four NR3C1 polymorphisms and the muscle response to resistance training (RT). European-American adults (n = 602, 23.8±0.4yr) completed a 12 week unilateral arm RT program. Maximum voluntary contraction (MVC) assessed isometric strength (kg) and MRI assessed biceps size (cm2) pre- and post-resistance training. Subjects were genotyped for NR3C1 -2722G>A, -1887G>A, -1017T>C, and +363A>G. Men carrying the -2722G allele gained less relative MVC (17.3±1.2vs33.5±6.1%) (p = 0.010) than AA homozygotes; men with -1887GG gained greater relative MVC than A allele carriers (19.6±1.4vs13.2±2.3%) (p = 0.016). Women carrying the -1017T allele gained greater relative size (18.7±0.5vs16.1±0.9%) (p = 0.016) than CC homozygotes. We found sex-specific NR3C1 associations with the muscle strength and size response to RT. Future studies should investigate whether these associations are partially explained by cortisol's actions in muscle tissue as they interact with sex differences in cortisol production.

Background: Meta-analysis of genome-wide association studies identified obesity-related genetic variants. Due to the pleiotropic effects of related phenotypes, we tested six of these obesity-related genetic variants for their association with physical activity: fat mass and obesity-associated ( FTO )(rs9939609)T>A, potassium channel tetramerization domain containing ( KCTD15 ) (rs11084753)G>A, melanocortin receptor4 ( MC4R )(rs17782313)T>C, neuronal growth regulator 1 ( NEGR1 )(rs2815752)A>G, SH2B adapter protein 1 ( SH2B1 )(rs7498665)A>G, and transmembrane protein18 ( TMEM18 )(rs6548238)C>T., Method: European-American women ( n  = 263) and men ( n  = 229) (23.5 ± 0.3 years, 24.6 ± 0.2 kg/m 2 ) were genotyped and completed the Paffenbarger physical activity Questionnaire. Physical activity volume in metabolic energy equivalents [MET]-hour/week was derived from the summed time spent (hour/week) times the given MET value for vigorous, moderate, and light intensity physical activity, and sitting and sleeping, respectively. Multivariable adjusted [(age, sex, and body mass index (BMI)] linear regression tested associations among genotype (dominant/recessive model) and the log of physical activity volume., Result: MC4R (rs17782313)T>C explained 1.1 % ( p  = 0.02), TMEM18 (rs6548238)C>T 1.2 % ( p  = 0.01), and SH2B1 (rs7498665)A>G 0.6 % ( p  = 0.08) of the variability in physical activity volume. Subjects with the MC4R C allele spent 3.5 % less MET-hour/week than those with the TT genotype ( p  = 0.02). Subjects with the TMEM18 T allele spent 4.1 % less MET-hour/week than those with the CC genotype ( p  = 0.01). Finally, subjects with the SH2B1 GG genotype spent 3.6 % less MET-hour/week than A allele carriers ( p  = 0.08)., Conclusion: Our findings suggest a shared genetic influence among some obesity-related gene loci and physical activity phenotypes that should be explored further. Physical activity volume differences by genotype have public health importance equating to 11-13 lb weight difference annually.

The purpose of this study was to examine whether leptin levels affect the response of leptin to exercise training (ET) and whether this is also affected by C-reactive protein (CRP) or the three common Apolipoprotein E genotypes (APOE). Ninety-seven (male = 45, female = 52) sedentary individuals underwent 6 months of supervised ET. Blood was sampled before the initiation of ET, and again 24 and 72 hr after completion of the final training session. ET resulted in a small reduction in body mass (80.47 ± 18.03 vs 79.42 ± 17.34 kg, p < .01). Leptin was reduced 24 hr after the final exercise session (p < .01), but returned to normal after 72 hr (p > .05)--Pre: 13.51 ± 12.27, 24hr: 12.14 ± 12.34, 72 hr: 12.98 ± 11.40 ng/ml. The most hyperleptinemic individuals had a greater initial response, which was sustained through to 72 hr after the final session in the pooled study population (p < .01), and in both males (p < .05) and females (p < .05) separately. CRP was related to leptin independently of body weight and positively related to the reductions in leptin. APOE genotype was not related to leptin levels and did not affect the response to ET. Leptin levels may only be reduced by ET in those with hyperleptinemia. In addition, both the initial extent of hyperleptinemia and the subsequent reduction in leptin may be related to low grade chronic systemic inflammation.

Genome-wide association studies have identified thousands of variants that are associated with numerous phenotypes. One such variant, rs13266634, a nonsynonymous single nucleotide polymorphism in the solute carrier family 30 (zinc transporter) member eight gene, is associated with a 53% increase in the risk of developing type 2 diabetes (T2D). We hypothesized that individuals with the protective allele against T2D would show a positive response to short-term and long-term resistance exercise. Two cohorts of young adults-the Eccentric Muscle Damage (EMD; n = 156) cohort and the Functional Single Nucleotide Polymorphisms Associated with Muscle Size and Strength Study (FAMuSS; n = 874)-were tested for association of the rs13266634 variant with measures of skeletal muscle response to resistance exercise. Our results were sexually dimorphic in both cohorts. Men in the EMD study with two copies of the protective allele showed less post-exercise bout strength loss, less soreness, and lower creatine kinase values. In addition, men in the FAMuSS, homozygous for the protective allele, showed higher pre-exercise strength and larger arm skeletal muscle volume, but did not show a significant difference in skeletal muscle hypertrophy or strength with resistance training.

The purpose of this study was to evaluate the anthropometric characteristics and fitness levels of elite level under 18 (U-18) Gaelic football players to establish normative centile scores for selected fitness parameters and to compare the physical and fitness characteristics relative to each playing position. A total of 265 male U-18 Gaelic football players (age: 16.96 ± 0.7 years; height: 178.11 ± 6.27 cm; weight: 72.07 ± 8.68 kg) participated in the study. According to positional roles, players were categorized as goalkeepers (n = 13), defenders (n = 113), midfielders (n = 30), and forwards (n = 109). Height and weight were measured, and skinfolds were taken before participants sequentially performed a sit and reach test (S&R), countermovement jump (CMJ), standing long jump (SLJ), 5- and 20-m speed test, and the Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1). The percentage body fat was higher (p < 0.01) in goalkeepers than the other playing positions. Goalkeepers had a higher body mass index than defenders (p < 0.05) and forwards (p < 0.01). Midfielders and goalkeepers were taller (p < 0.01) and heavier (p < 0.01) than defenders and forwards. The total distance covered in the YYIRT1 was significantly lower (p < 0.01) in goalkeepers than the other playing positions. There was no significant positional difference in the performance scores in the S&R test, CMJ, SLJ, and 5- and 20-m running speed. The study findings indicate minimal differences in the anthropometric and physiological characteristics between playing positions in elite youth level Gaelic football players. The norm-referenced percentile scores will enable conditioning coaches to benchmark elite performance and design training programs.

Purpose: An osteopontin (OPN; SPP1) gene promoter polymorphism modifies disease severity in Duchenne muscular dystrophy, and we hypothesized that it might also modify muscle phenotypes in healthy volunteers., Methods: Gene association studies were carried out for OPN (rs28357094) in the FAMuSS cohort (n = 752; mean ± SD age = 23.7 ± 5.7 yr). The phenotypes studied included muscle size (MRI), strength, and response to supervised resistance training. We also studied 147 young adults that had carried out a bout of eccentric elbow exercise (age = 24.0 ± 5.2 yr). Phenotypes analyzed included strength, soreness, and serum muscle enzymes., Results: In the FAMuSS cohort, the G allele was associated with 17% increase in baseline upper arm muscle volume only in women (F = 26.32; P = 5.32 × 10), explaining 5% of population variance. In the eccentric damage cohort, weak associations of the G allele were seen in women with both baseline myoglobin and elevated creatine kinase. The sexually dimorphic effects of OPN on muscle were also seen in OPN-null mice. Five of seven muscle groups examined showed smaller size in OPN-null female mice, whereas two were smaller in male mice. The query of OPN gene transcription after experimental muscle damage in mice showed rapid induction within 12 h (100-fold increase from baseline), followed by sustained high-level expression through 16 d of regeneration before falling to back to baseline., Conclusion: OPN is a sexually dimorphic modifier of muscle size in normal humans and mice and responds to muscle damage. The OPN gene is known to be estrogen responsive, and this may explain the female-specific genotype effects in adult volunteers.

Purpose: We investigated the influence of Leptin (LEP) and leptin receptor (LEPR) SNPs on habitual physical activity (PA) and body composition response to a unilateral, upper body resistance training (RT) program., Methods: European-derived American volunteers (men=111, women=131, 23.4 ± 5.4 yr, 24.4 ± 4.6 kg·m(-2)) were genotyped for LEP 19 G>A (rs2167270), and LEPR 326 A>G (rs1137100), 668 A>G (rs1137101), 3057 G>A (rs1805096), and 1968 G>C (rs8179183). They completed the Paffenbarger PA Questionnaire. Arm muscle and subcutaneous fat volumes were measured before and after 12 wk of supervised RT with MRI. Multivariate and repeated measures ANCOVA tested differences among phenotypes by genotype and gender with age and body mass index as covariates., Results: Adults with the LEP 19 GG genotype reported more kcal/wk in vigorous intensity PA (1273.3 ± 176.8, p=0.017) and sports/recreation (1922.8 ± 226.0, p<0.04) than A allele carriers (718.0 ± 147.2, 1328.6 ± 188.2, respectively). Those with the LEP 19 GG genotype spent more h/wk in light intensity PA (39.7 ± 1.6) than A allele carriers (35.0 ± 1.4, p=0.03). In response to RT, adults with the LEPR 668 G allele gained greater arm muscle volume (67,687.05 ± 3186.7 vs. 52,321.87 ± 5125.05 mm(3), p=0.01) and subcutaneous fat volume (10,599.89 ± 3683.57 vs. -5224.73 ± 5923.98 mm(3), p=0.02) than adults with the LEPR 668 AA genotype, respectively., Conclusion: LEP19 G>A and LEPR 668 A>G associated with habitual PA and the body composition response to RT. These LEP and LEPR SNPs are located in coding exons likely influencing LEP and LEPR function. Further investigation is needed to confirm our findings and establish mechanisms for LEP and LEPR genotype and PA and body composition associations we observed., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Many of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS), it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects., Methods: Using a randomized cross-over design, very low density lipoprotein (VLDL) responses were evaluated in eight men on the morning after i) an inactive control trial (CON), ii) exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF), and iii) after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL)., Results: The intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG) determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70-120 nm (large) particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43-55 nm (medium) particle range. VLDL-TG in smaller particles (29-43 nm) was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL) activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state., Conclusions: These findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in LPL activity.

Background: Quadriceps femoris muscle (QFM) weakness is a feature of knee osteoarthritis (OA) and exercise programs that strengthen this muscle group can improve function, disability and pain. Traditional supervised resistance exercise is however resource intensive and dependent on good adherence which can be challenging to achieve in patients with significant knee OA. Because of the limitations of traditional exercise programs, interest has been shown in the use of neuromuscular electrical stimulation (NMES) to strengthen the QFM. We conducted a single-blind, prospective randomized controlled study to compare the effects of home-based resistance training (RT) and NMES on patients with moderate to severe knee OA., Methods: 41 patients aged 55 to 75 years were randomised to 6 week programs of RT, NMES or a control group receiving standard care. The primary outcome was functional capacity measured using a walk test, stair climb test and chair rise test. Additional outcomes were self-reported disability, quadriceps strength and cross-sectional area. Outcomes were assessed pre- and post-intervention and at 6 weeks post-intervention (weeks 1, 8 and 14 respectively)., Results: There were similar, significant improvements in functional capacity for the RT and NMES groups at week 8 compared to week 1 (p ≤ 0.001) and compared to the control group (p < 0.005), and the improvements were maintained at week 14 (p ≤ 0.001). Cross sectional area of the QFM increased in both training groups (NMES: +5.4%; RT: +4.3%; p = 0.404). Adherence was 91% and 83% in the NMES and RT groups respectively (p = 0.324)., Conclusions: Home-based NMES is an acceptable alternative to exercise therapy in the management of knee OA, producing similar improvements in functional capacity., Trial Registration: Current Controlled Trials ISRCTN85231954.

Ankyrin repeat domain 6 (ANKRD6) is a ubiquitous protein that associates with early development in mammals and is highly expressed in the brain, spinal cord, and heart of humans. We examined the role of 8 ANKRD6 single-nucleotide polymorphisms (SNPs) on muscle performance and habitual physical activity (PA). Single-nucleotide polymorphisms were 545 T>A (rs9362667), 485 M>L (rs61736690), 233 T>M (rs2273238), 128 I>L (rs3748085), 631 P>L (rs61739327), 122 Q>E (rs16881983), 197805 G>A (rs9344950), and 710 L>X (NOVEL). This study consisted of 922 healthy, untrained, European-derived American men (n = 376, 23.6 ± 0.3 years, 25.0 ± 0.2 kg·m(-2)) and women (n = 546, 23.2 ± 0.2 years, 24.0 ± 0.2 kg·m(-2)). Muscle strength (maximum voluntary contraction [MVC] and 1 repetition maximum [1RM]) and size (cross-sectional area [CSA]) were assessed before and after 12 weeks of unilateral resistance training (RT). A subsample (n = 536, 23.4 ± 0.2 years, 24.6 ± 0.2 kg·m(-2)) completed the Paffenbarger Physical Activity Questionnaire. Associations among ANKRD6 genotypes and muscle phenotypes were tested with repeated measure analysis of covariance (ANCOVA) and PA phenotypes with multivariate ANCOVA, with age and body mass index as covariates. ANKRD6 122 Q>E was associated with increased baseline biceps CSA. ANKRD6 545 A>T and ANKRD6 710 L>X were associated with increased 1RM and MVC in response to RT, respectively. ANKRD6 631 P>L was associated with increased biceps CSA response to RT and time spent in moderate-intensity PA among the total sample and women. ANKRD6 genetic variants were associated with the muscle size and strength response to RT and habitual PA levels. Further research is needed to validate our results and explore mechanisms for the associations we observed.

Background: Emerging data have revealed a negative association between adiposity and muscle quality (MQ). There is a lack of research to examine this interaction among young, healthy individuals, and to evaluate the contribution of adiposity to adaptation after resistance exercise (RE)., Objective: The purpose of this investigation was to examine the influence of subcutaneous adipose tissue (SAT) on muscle function among non-obese individuals before and after RE., Design: Analyses included 634 non-obese (body mass index <30 kg m(-2)) subjects (253 males, 381 females; age=23.3 ± 5.2 years). SAT and muscle mass (magnetic resonance imaging-derived SAT and biceps muscle volume), isometric and dynamic biceps strength, and MQ (strength/muscle volume), were analyzed at baseline and after 12 weeks of unilateral RE., Results: At baseline, SAT was independently associated with lower MQ for males (β=-0.55; P<0.01) and females (β=-0.45; P<0.01), controlling for body mass and age. Adaptation to RE revealed a significant negative association between SAT and changes for strength capacity (β=-0.13; p=0.03) and MQ (β=-0.14; P<0.01) among males. No attenuation was identified among females. Post-intervention SAT remained a negative predictor of MQ for males and females (β=-0.47; P<0.01)., Conclusions: The findings reveal that SAT is a negative predictor of MQ among non-obese, healthy adults, and that after 12 weeks of progressive RE this association was not ameliorated. Data suggest that SAT exerts a weak, negative influence on the adaptive response to strength and MQ among males.

An increase in serum osteoprotegerin (OPG) is associated with type 2 diabetes mellitus, the severity of vascular calcification, and coronary artery disease. Obesity is a risk factor for diabetes and cardiovascular disease, but little is known about the relationship between OPG and obesity. The purpose of this study was to determine if changes in body mass index (BMI) and insulin sensitivity influence circulating OPG in healthy subjects. A total of 100 subjects (36 lean, 41 overweight, and 23 obese) with normal glucose tolerance, blood pressure, and electrocardiogram stress test result volunteered for this study. Insulin sensitivity was estimated using a 2-hour oral glucose tolerance test with oral glucose insulin sensitivity analysis. Osteoprotegerin, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL),soluble receptor activator of nuclear factor-κβ ligand (sRANKL), and adiponectin were analyzed using commercially available enzyme-linked immunosorbent assays. Osteoprotegerin (P < .01) and adiponectin (P < .001) were significantly decreased in the obese compared with lean subjects. There was no significant difference between BMI categories for TRAIL or sRANKL. Controlling for age and sex, there was a significant correlation between OPG and adiponectin (r = 0.391, P < .001), BMI (r = -0.331, P < .001), waist circumference (r = -0.268, P < .01), homeostasis model assessment of insulin resistance (r = -0.222, P < .05), and oral glucose insulin sensitivity (r = 0.221, P < .05). Both OPG and adiponectin were negatively correlated with body weight, BMI, waist circumference, and fasting plasma insulin while being positively correlated with insulin sensitivity (P < .05). Controlling for age, sex, and BMI, TRAIL was positively related to fat mass (r = 0.373, P < .001) and waist circumference (r = 0.257, P < .05). In contrast to patients with type 2 diabetes mellitus, circulating OPG is lower in obese, but otherwise healthy subjects and is positively correlated with indices of insulin sensitivity., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Genome-wide association studies (GWASs) have identified polymorphic loci associated with coronary artery disease (CAD) risk factors (i.e. serum lipids) in adult populations (42-69 y). We hypothesized that younger populations would show a greater relative genetic component due to fewer confounding variables. We examined the influence of 20 GWAS loci associated with serum lipids and insulin metabolism, in a university student cohort (n = 548; mean age = 24 y), and replicated statistically associated results in a second study cohort of primary school students (n = 810, mean age = 11.5 y). Nineteen loci showed no relationship with studied risk factors in young adults. However, the ancestral allele of the rs646776 (SORT1) locus was strongly associated with increased LDL (C) in young adults [TT: 97.6 ± 1.0 mg/dL (n = 345) versus CT/CC: 87.3 ± 1.0 mg/dL (n = 203); p = 3 × 10(x6)] and children [TT: 94.0 ± 1.3 mg/dL (n = 551) versus CT/CC: 84.7 ± 1.4 mg/dL (n = 259); p = 4 × 10(x6)]. This locus is responsible for 3.6% of population variance in young adults and 2.5% of population variance in children. The effect size of the SORT1 locus is considerably higher in young populations (2.5-4.1%) compared with older subjects (1%).

Hepatic lipase (HL) and lipoprotein lipase (LPL) activities (HLA, LPLA) modify lipoproteins and facilitate their binding to hepatic receptors. Apolipoprotein E (APOE) physically interacts with the lipases, and the three common haplotypes of the APOE gene (ε2, ε3, and ε4) yield protein isoforms (E2, E3, and E4, respectively) that are functionally different. Lipase activities themselves differ by sex and exercise training status. The interaction of APOE genotype, exercise training, and sex effects on lipase activities has not been studied. We measured postheparin plasma lipase activities in normolipidemic men and women with the three most common APOE genotypes, which are the haplotype combinations ε2/ε3 (n = 53 ), ε3/ε3 (n = 62), and ε4/ε3 (n = 52), enrolled in 6 mo of aerobic exercise training. These haplotype combinations comprise an estimated 11.6, 62.3, and 21.3% of the population, respectively. Baseline HLA was 35% lower in women than in men (P < 0.0001). In men but not women, HLA was higher in ε2/ε3 group compared with ε4/ε3 (P = 0.01) and ε3/ε3 (P = 0.05). Neither sex nor APOE genotype affected baseline LPLA. Training decreased HLA by 5.2% (P = 0.018) with no APOE effect. The apparent increase in LPLA following exercise was significant and APOE dependent only when corrected for baseline insulin (P < 0.05). Exercise decreased LPLA by 0.8 μmol free fatty acid (FFA)·ml⁻¹·h⁻¹ (-6%) in ε3/ε3 compared with the combined increases of 6.6% in ε2/ε3 and 12% in ε4/ε3 (P = 0.018 vs. ε3/ε3). However, these differences were statistically significant only after correcting for baseline insulin. We conclude that common APOE genotypes interact with 1) sex to modulate HLA regardless of training status, with ε2/ε3 men demonstrating higher HLA than ε3/ε3 or ε4/ε3 men, and 2) aerobic training to modulate LPLA, regardless of sex, with ε3/ε3 subjects showing a significant decrease compared with an increase in ε2/ε3 and ε3/ε4 after controlling for baseline insulin.

Recently, a genome-wide association study (GWAS) that identified eight single-nucleotide polymorphisms (SNPs) associated with BMI highlighted a possible neuronal influence on the development of obesity. We hypothesized these SNPs would govern the response of BMI and subcutaneous fat to resistance training in young individuals (age = 24 years). We genotyped the eight GWAS-identified SNPs in the article by Willer et al. in a cohort (n = 796) that undertook a 12-week resistance-training program. Females with a copy of the rare allele (C) for rs17782313 (MC4R) had significantly higher BMIs (, Cc/ct: n = 174; 24.70 ± 0.33 kg/m², TT: n = 278; 23.41 ± 0.26 kg/m², P = 0.002), and the SNP explained 1.9% of overall variation in BMI. Males with a copy of the rare allele (T) for rs6548238 (TMEM18) had lower amounts of subcutaneous fat pretraining (CT/TT: n = 65; 156,534 ± 7,415 mm³, CC: n = 136; 177,825 ± 5,139 mm³, P = 0.019) and males with a copy of the rare allele (A) for rs9939609 (FTO) lost a significant amount of subcutaneous fat with exercise (, At/aa: n = 83; -798.35 ± 2,624.30 mm³, TT: n = 47; 9,435.23 ± 3,494.44 mm³, P = 0.021). Females with a copy of the G allele for a missense variant in the SH2B1 (rs7498665) was associated with less change of subcutaneous fat volume with exercise (, Ag/gg: n = 191; 9,813 ± 2,250 mm³ vs. AA: n = 126; 770 ± 2,772 mm³; P = 0.011). These data support the original finding that there is an association between measures of obesity and a variant near the MC4R gene and extends these results to a younger population and implicates FTO, TMEM18, and SH2B1 polymorphisms in subcutaneous fat regulation.

Converging lines of evidence suggest that AKT1 is a major mediator of the responses to insulin,insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. We hypothesized that AKT1 variants may play a role in the endophenotypes that makeup metabolic syndrome. We studied a 12-kb region including the first exon of the AKT1 gene for association with metabolic syndrome-related phenotypes in four study populations [FAMUSS cohort (n = 574; age 23.7 ± 5.7 years), Strong Heart Study (SHS) (n = 2,134; age 55.5 ± 7.9 years), Dynamics of Health, Aging and Body Composition (Health ABC) (n = 3,075; age 73.6 ± 2.9 years), and Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE)(n = 175; age 40–65 years)]. We identified a three SNP haplotype that we call H1, which represents the ancestral alleles eles at the three loci and H2, which represents the derived alleles at the three loci. In young adult European Americans (FAMUSS), H1 was associated with higher fasting glucose levels in females. In middle age Native Americans (SHS), H1 carriers showed higher fasting insulin and HOMA in males, and higher BMI in females. Inolder African-American and European American subjects(Health ABC) H1 carriers showed a higher incidence of metabolic syndrome. Homozygotes for the H1 haplotype showed about twice the risk of metabolic syndrome in both males and females (p < 0.001). In middle-aged European Americans with insulin resistance (STRRIDE) studied by intravenous glucose tolerance test (IVGTT), H1 carriers showed increased insulin resistance due to the Sg component (p = 0.021). The 12-kb haplotype is a risk factor for metabolic syndrome and insulin resistance that needs to be explored in further populations.

Baseline muscle size and muscle adaptation to exercise are traits with high variability across individuals. Recent research has implicated several chemokines and their receptors in the pathogenesis of many conditions that are influenced by inflammatory processes, including muscle damage and repair. One specific chemokine, chemokine (C-C motif) ligand 2 (CCL2), is expressed by macrophages and muscle satellite cells, increases expression dramatically following muscle damage, and increases expression further with repeated bouts of exercise, suggesting that CCL2 plays a key role in muscle adaptation. The present study hypothesizes that genetic variations in CCL2 and its receptor (CCR2) may help explain muscle trait variability. College-aged subjects [n = 874, Functional Single-Nucleotide Polymorphisms Associated With Muscle Size and Strength (FAMUSS) cohort] underwent a 12-wk supervised strength-training program for the upper arm muscles. Muscle size (via MR imaging) and elbow flexion strength (1 repetition maximum and isometric) measurements were taken before and after training. The study participants were then genotyped for 11 genetic variants in CCL2 and five variants in CCR2. Variants in the CCL2 and CCR2 genes show strong associations with several pretraining muscle strength traits, indicating that inflammatory genes in skeletal muscle contribute to the polygenic system that determines muscle phenotypes. These associations extend across both sexes, and several of these genetic variants have been shown to influence gene regulation.

Previous studies have reported associations of polymorphisms in the IGF1 gene with phenotypes of body composition (BC). The purpose of this study was to identify phenotypes of BC and physical function that were associated with the IGF1 promoter polymorphism (rs35767, -C1245T). Subjects from the Health, Aging, and Body Composition Study, white males and females (n = 925/836) and black males and females (533/705) aged 70-79 years were genotyped for the polymorphism. Phenotypes of muscle size and function, bone mineral density, and BC were analyzed for associations with this polymorphism. To validate and compare these findings, a cohort of young (mean age = 24.6, SD = 5.9) white men and women (n = 173/296) with similar phenotypic measurements were genotyped. An association with BC was identified in elderly females when significant covariates (physical activity, age, smoking status, body mass index) were included. White women with C/C genotype had 3% more trunk fat and 2% more total fat than those with C/T (P < 0.05). Black women with C/C genotype had 3% less total lean mass and 3% less muscle mass than their T/T counterparts (P < 0.05). Associations were identified with muscle strength in white women (P < 0.01) that were in agreement with the C/C genotype having lower muscle function. Thus, in an elderly population but not a young population, a polymorphism in the IGF1 gene may be predictive of differences in body composition, primarily in black females.

Background: Supervised preoperative muscle strengthening programmes (prehabilitation) can improve recovery after total joint arthroplasty but are considered resource intensive. Neuromuscular electrical stimulation (NMES) has been shown to improve quadriceps femoris muscle (QFM) strength and clinical function in subjects with knee osteoarthritis (OA) however it has not been previously investigated as a prehabilitation modality., Methods: This pilot study assessed the compliance of a home-based, NMES prehabilitation programme in patients undergoing total knee arthroplasty (TKA). We evaluated its effect on preoperative and postoperative isometric quadriceps femoris muscle (QFM) strength, QFM cross-sectional area (CSA) and clinical function (subjective and objective). Seventeen subjects were recruited with 14 completing the study (NMES group n = 9; Control group n = 5)., Results: Overall compliance with the programme was excellent (99%). Preoperative QFM strength increased by 28% (p > 0.05) with associated gains in walk, stair-climb and chair-rise times (p < 0.05). Early postoperative strength loss (approximately 50%) was similar in both groups. Only the NMES group demonstrated significant strength (53.3%, p = 0.011) and functional recovery (p < 0.05) from 6 to 12 weeks post-TKA. QFM CSA decreased by 4% in the NMES group compared to a reduction of 12% in the control group (P > 0.05) at 12 weeks postoperatively compared to baseline. There were only limited associations found between objective and subjective functional outcome instruments., Conclusions: This pilot study has shown that preoperative NMES may improve recovery of quadriceps muscle strength and expedite a return to normal activities in patients undergoing TKA for OA. Recommendations for appropriate outcome instruments in future studies of prehabilitation in TKA have been provided.

Skeletal muscle contraction increases intracellular ATP turnover, calcium flux, and mechanical stress, initiating signal transduction pathways that modulate peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha)-dependent transcriptional programmes. The purpose of this study was to determine if the intensity of exercise regulates PGC-1alpha expression in human skeletal muscle, coincident with activation of signalling cascades known to regulate PGC-1alpha transcription. Eight sedentary males expended 400 kcal (1674 kj) during a single bout of cycle ergometer exercise on two separate occasions at either 40% (LO) or 80% (HI) of . Skeletal muscle biopsies from the m. vastus lateralis were taken at rest and at +0, +3 and +19 h after exercise. Energy expenditure during exercise was similar between trials, but the high intensity bout was shorter in duration (LO, 69.9 +/- 4.0 min; HI, 36.0 +/- 2.2 min, P < 0.05) and had a higher rate of glycogen utilization (P < 0.05). PGC-1alpha mRNA abundance increased in an intensity-dependent manner +3 h after exercise (LO, 3.8-fold; HI, 10.2-fold, P < 0.05). AMP-activated protein kinase (AMPK) (2.8-fold, P < 0.05) and calcium/calmodulin-dependent protein kinase II (CaMKII) phosphorylation (84%, P < 0.05) increased immediately after HI but not LO. p38 mitogen-activated protein kinase (MAPK) phosphorylation increased after both trials (2.0-fold, P < 0.05), but phosphorylation of the downstream transcription factor, activating transcription factor-2 (ATF-2), increased only after HI (2.4-fold, P < 0.05). Cyclic-AMP response element binding protein (CREB) phosphorylation was elevated at +3 h after both trials (80%, P < 0.05) and class IIa histone deacetylase (HDAC) phosphorylation increased only after HI (2.0-fold, P < 0.05). In conclusion, exercise intensity regulates PGC-1alpha mRNA abundance in human skeletal muscle in response to a single bout of exercise. This effect is mediated by differential activation of multiple signalling pathways, with ATF-2 and HDAC phosphorylation proposed as key intensity-dependent mediators.

Unlabelled: Participation in regular aerobic exercise has been shown to increase arterial size and that exercise-induced vascular remodeling may be regional rather than systemic. However, these issues have been minimally investigated concerning resistance training., Purposes: To determine whether 1) resistance training of the nondominant arm elicits an increase in diameter of the brachial artery and 2) unilateral training induces arterial remodeling in the contralateral arm., Methods: Twenty-four previously untrained participants, consisting of 18 females (aged 22.3 +/- 5.1 yr) and 6 males (aged 21.7 +/- 1.8 yr), participated in unilateral strength training of the biceps and triceps for 12 wk using their nondominant arm. Isotonic (one-repetition maximum, 1RM) and isometric (ISO) strength of the biceps were assessed before and after training on both arms. Brachial artery diameter and biceps muscle cross-sectional area (CSA) of both arms were also measured before and after training using magnetic resonance imaging (MRI)., Results: Brachial artery diameter increased 5.47% (P < 0.05) in the nondominant trained arm with no change observed in the dominant untrained arm. Biceps CSA increased 18.3% (P < 0.05) in the trained arm with no change (P > 0.05) in the untrained limb. Nondominant 1RM and ISO strength increased by 35.1% and 16.8%, respectively (P < 0.05 for both), although there were no significant changes (P > 0.05) in the contralateral arm. A modest correlation was found between the increases in CSA and in brachial artery diameter (r2 = 0.19, P = 0.039)., Conclusions: These results indicate that upper arm vascular remodeling, manifesting as increased brachial artery diameter, can result from resistance training and that these changes are localized to the trained limb and associated with increases in CSA.

The present study examined associations between the ciliary neurotrophic factor (CNTF) 1357 G --> A polymorphism and the muscle strength response to a unilateral, upper arm resistance-training (RT) program among healthy, young adults. Subjects were 754 Caucasian men (40%) and women (60%) who were genotyped and performed a training program of the nondominant (trained) arm with the dominant (untrained) arm as a comparison. Peak elbow flexor strength was measured with one repetition maximum, isometric strength with maximum voluntary contraction, and bicep cross-sectional area with MRI in the trained and untrained arms before and after training. Women with the CNTF GG genotype gained more absolute isometric strength, as measured by MVC (6.5 +/- 0.3 vs. 5.2 +/- 0.5 kg), than carriers of the CNTF A1357 allele in the trained arm pre- to posttraining (P < 0.05). No significant associations were seen in men. Women with the CNTF GG genotype gained more absolute dynamic (1.0 +/- 0.1 vs. 0.6 +/- 0.1 kg) and allometric (0.022 +/- 0.0 vs. 0.015 +/- 0.0 kg/kg(-0.67)) strength, as measured by 1 RM, than carriers of the CNTF A1357 allele in the untrained arm pre- to posttraining (P < 0.05). No significant associations were seen in men. No significant associations, as measured by cross-sectional area, were seen in men or women. The CNTF 1357 G --> A polymorphism explains only a small portion of the variability in the muscle strength response to training in women.

The purpose of this study was to assess the association of age with muscle mass and strength in a group of young adults before and after 12 weeks of progressive resistance training. Eight hundred twenty-six young males and females (age 24.34 +/- 5.69 yr, range 18-39 yr) completed a strictly supervised 12-week unilateral resistance training program of the nondominant arm. Isometric (maximal voluntary contraction [MVC]) and dynamic strength (1 repetition maximum [1RM]) of the elbow flexors and cross-sectional area (CSA) of the biceps-brachii using magnetic resonance imaging (MRI) scans were measured before and after training. Pearson correlation coefficients were calculated for size and strength variables and age. In addition, the cohort was divided into groups according to decade of life and differences assessed by analysis of variance. Age correlated significantly and positively with all pretraining measures of muscle size and strength (CSA: r = 0.191, p < 0.001; MVC: r = 0.109, p = 0.002; 1RM: r = 0.109, p = 0.002). Age was not related to the training-induced changes in CSA or MVC but was negatively associated with the change in 1RM (r = -0.217, p < 0.001). The study indicates that age does have a significant positive relationship with muscle size and strength in untrained young adults. Although age was negatively associated with improvements in 1RM, the effect of age was small relative to the improvements induced through resistance training, thus suggesting age does not limit response to training in any practical way during early adulthood.

A classic morphogen, bone morphogenetic protein 2 (BMP2) regulates the differentiation of pluripotent mesenchymal cells. High BMP2 levels promote osteogenesis or chondrogenesis and low levels promote adipogenesis. BMP2 inhibits myogenesis. Thus, BMP2 synthesis is tightly controlled. Several hundred nucleotides within the 3' untranslated regions of BMP2 genes are conserved from mammals to fishes indicating that the region is under stringent selective pressure. Our analyses indicate that this region controls BMP2 synthesis by post-transcriptional mechanisms. A common A to C single nucleotide polymorphism (SNP) in the BMP2 gene (rs15705, +A1123C) disrupts a putative post-transcriptional regulatory motif within the human ultra-conserved sequence. In vitro studies indicate that RNAs bearing the A or C alleles have different protein binding characteristics in extracts from mesenchymal cells. Reporter genes with the C allele of the ultra-conserved sequence were differentially expressed in mesenchymal cells. Finally, we analyzed MRI data from the upper arm of 517 healthy individuals aged 18-41 years. Individuals with the C/C genotype were associated with lower baseline subcutaneous fat volumes (P = 0.0030) and an increased gain in skeletal muscle volume (P = 0.0060) following resistance training in a cohort of young males. The rs15705 SNP explained 2-4% of inter-individual variability in the measured parameters. The rs15705 variant is one of the first genetic markers that may be exploited to facilitate early diagnosis, treatment, and/or prevention of diseases associated with poor fitness. Furthermore, understanding the mechanisms by which regulatory polymorphisms influence BMP2 synthesis will reveal novel pharmaceutical targets for these disabling conditions., ((c) 2009 Wiley-Liss, Inc.)

Triglyceride-rich postprandial lipoproteins are known to activate endothelial cells in vitro, contributing to atherosclerosis. Endothelial microparticles (EMP) are membranous vesicles released into the circulation from vascular endothelial cells that permit cell activation to be monitored in vivo. The objective of the study was to examine changes in EMP following a high fat meal, consumed with and without prior exercise. Eight recreationally active young men underwent two oral fat tolerance tests following either 100 min exercise at 70% VO(2)peak (EX trial) or no exercise (CON trial) on the previous evening. Postprandial triglycerides were reduced (1.97 +/- 0.31 vs. 1.17 +/- 0.13 mmol L(-1), p < 0.05) and HDL-cholesterol (HDL-C) increased (1.20 +/- 0.07 vs. 1.30 +/- 0.08 mmol L(-1), p < 0.05) in the EX compared to CON trial. EMP (CD31+/42b-) increased postprandially (p < 0.05). However, counts were not different between trials (postprandial CON and EX trial counts x 10(3 )microL(-1), 3.10 +/- 0.14 vs. 3.26 +/- 0.37). There were no changes in sICAM-1 or sVCAM-1 postprandially and no differences between trials. Interleukin-6 (IL-6) and leukocytes increased postprandially (p < 0.05). IL-6 values were not different between trials. Leukocytes were higher at 0 h in the EX trial with CON and EX trial values similar at 6 h. EMP, but not sICAM-1 or sVCAM-1, increase in response to a high fat meal. However, EMP are not attenuated by acute exercise, despite a considerable reduction in postprandial lipemia and an increase in HDL-C.

Postprandial lipemia (PPL) is associated with impaired endothelial function and inflammation. Acute exercise reduces PPL in adults. This investigation examined the effect of an acute bout of exercise on postprandial changes in triglycerides (TG), glucose, insulin, inflammation [white blood cell count (WBC), interleukin-6 (IL-6) tumor necrosis factor-alpha, C-reactive protein (CRP)] and endothelial activation [soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1)] following a high-fat meal in adolescents. Ten normal weight (NW) (BMI, 20.9 +/- 1.7 kg m(-2); 15.6 +/- 0.7 years) and eight overweight (OW) (BMI, 28.3 +/- 3.6 kg m(-2); 15.9 +/- 0.4 years) adolescent boys underwent two 6-h oral fat tolerance tests (OFTT) separated by 7-10 days. On the evening prior to each OFTT, subjects either rested or completed a treadmill exercise bout (65% V(O)(2max); 600 kcal expended). Exercise reduced (P < 0.01) the postprandial TG area under the curve by approximately 20% in the NW and OW groups. The postprandial glucose and insulin response did not differ between the control and exercise trials or between the NW and OW groups. Circulating leukocytes and plasma IL-6 levels increased (P < 0.01) in the NW and OW groups 6 h following the OFTT in both experimental conditions. There were no changes in CRP, sVCAM-1 or sICAM-1 following the OFTT and there were no differences between experimental condition or NW and OW groups. In conclusion, a moderate exercise bout prior to a high-fat meal effectively reduces postprandial TG concentrations to a similar degree in both NW and OW adolescents, but does not reduce the concomitant postprandial increase in WBC or IL-6.

Purpose: We examined associations among myostatin (MSTN) 2379 A > G and 163 G > A and follistatin (FST) -5003 A > T and -833 G > T single nucleotide polymorphisms (SNP) on the muscle size and the strength response to resistance training (RT)., Methods: Subjects (n = 645, age = 24.1 +/- 0.2 yr, body mass index [BMI] = 24.2 +/- 0.2 kg x m(-2)) self-disclosed themselves as Caucasian (78.9%), African American (3.6%), Asian (8.4%), Hispanic (5.0%), or Other (4.2%). They were genotyped for MSTN 2379 A > G (n = 645), MSTN 163 G > A (n = 639), FST -5003 A > T (n = 580), and FST -833 G > T (n = 603). We assessed dynamic (one repetition maximum [1RM]) and isometric (maximum voluntary contraction [MVC]) muscle strength and size (cross-sectional area [CSA]) of the elbow flexors before and after 12 wk of unilateral upper-arm RT. Repeated-measures ANCOVA tested associations among genetic variants and muscle phenotypes with age and BMI as covariates., Results: Baseline MVC was greater among African Americans who were carriers of the MSTN G(2379) allele (AG/GG, n = 15) than the A2379A homozygotes (n = 8; 64.2 +/- 6.8 vs 49.8 +/- 8.7 kg). African Americans who were carriers of the FST T(-5003) allele (n = 12) had greater baseline 1RM (11.9 +/- 0.7 vs 8.8 +/- 0.5 kg) and CSA (24.4 +/- 1.3 vs 19.1 +/- 1.2 cm(2)) than African Americans with the A-5003A genotype (n = 14; P < 0.05). No MSTN or FST genotype and muscle phenotype associations were found among the other ethnic groups (P >or= 0.05)., Conclusion: MSTN 2379 A > G and FST -5003 A > T were associated with baseline muscle strength and size among African Americans only. These ethnic-specific associations are hypothesis generating and should be confirmed in a larger sample of African Americans.