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Background: The benefits of oral caffeine intake to enhance several aspects of physical performance, such as aerobic endurance, strength, power, and muscle endurance performance, are well supported. However, how the physical performance benefits of caffeine supplementation are translated into better specific actions in intermittent sports during real or simulated competition has been the topic of fewer investigations, and their results need to be appropriately reviewed and meta-analyzed. Objective: The aim of the study was to investigate the effects of acute caffeine intake on specific actions in intermittent sports involving decision making and high-intensity efforts (eg, team, racket, and combat sports) during real or simulated competitions. Methods: All studies included had blinded and crossover experimental designs, and we conducted a risk-of-bias analysis. In total, we included 24 studies. A meta-analysis was performed using the random-effects model to calculate the standardized mean difference (SMD) estimated by Hedges g and 95% CIs. Results: Caffeine ingestion increased high-intensity sport-specific actions during competition, such as the number of sprints (SMD: 0.48; 95% CI, 0.23–0.74), body impacts (SMD: 0.28; 95% CI, 0.08–0.49), accelerations (SMD: 0.35; 95% CI, 0.06–0.63), decelerations (SMD: 0.63; 95% CI, 0.12–1.14), and high-intensity offensive efforts (SMD: 0.36; 95% CI, 0.11–0.61). Additionally, caffeine ingestion induced a higher positive or success rate of actions during real or simulated competition (SMD: 0.44; 95% CI, 0.19–0.69). Conclusion: The current meta-analysis provides evidence of caffeine supplementation in increasing high-intensity efforts and the success rate of sport-specific actions during real or simulated competition. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze the reliability and validity of the predicted distance–time relationship in the severe-intensity domain from a 3-minute all-out running test (3MT). Methods: Twelve runners performed two 3MTs (test #1 and test #2) on an outdoor 400-m track after familiarization. Eighteen-hertz Global Positioning System data were used to estimate critical speed (CS) and distance covered above CS (D′). Time to cover 1200 and 3600 m (T1200 and T3600, respectively) was predicted using CS and D′ estimates from each 3MT. Eight runners performed 2 time trials in a single visit to assess real T1200 and T3600. Intraclass correlation coefficients (ICCs) and standard errors of measurement were calculated for reliability analysis. Results: Good to excellent reliability was found for CS, T1200, and T3600 estimates from 3MT (ICC >.95, standard error of measurement between 1.3% and 2.2%), and poor reliability was found for D′ (ICC =.55, standard error of measurement = 27%). Predictions from 3MT were significantly correlated to actual T1200 (r =.87 and.85 for test #1 and test #2, respectively) and T3600 (r =.91 and.82 for test #1 and test #2, respectively). The calculation of error prediction showed a systematic error between predicted and real T3600 (6.4% and 7.8% for test #1 and test #2, respectively, P <.01) contrary to T1200 (P >.1). Random error was between 4.4% and 6.1% for both distances. Conclusions: Despite low reliability of D′, 3MT yielded a reliable predicted distance–time relationship allowing repeated measures to evidence change with training adaptation. However, caution should be taken with prediction of performance potential of a single individual because of substantial random error and significant underestimation of T3600. [ABSTRACT FROM AUTHOR]

Introduction: The acute and isolated ingestion of sodium bicarbonate (NaHCO3) and caffeine (CAF) improves performance and delays fatigue in high-intensity tasks. However, it remains to be elucidated if the coingestion of both dietary supplements stimulates a summative ergogenic effect. This study aimed to examine the effect of the acute coingestion of NaHCO3 and CAF on repeated-sprint performance. Methods: Twenty-five trained participants (age: 23.3 [4.0] y; sex [female/male]: 12/13; body mass: 69.6 [12.5] kg) participated in a randomized, double-blind, placebo (PLA) -controlled, crossover study. Participants were assigned to 4 conditions: (1) NaHCO3 + CAF, (2) NaHCO3, (3) CAF, or (4) PLA. Thus, they ingested 0.3 g/kg of NaHCO3, 3 mg/kg of CAF, or PLA. Then, participants performed 4 Wingate tests (Wt), consisting of a 30-second all-out sprint against an individualized resisted load, interspersed by a 1.5-minute rest period between sprints. Results: Peak (Wpeak) and mean (Wmean) power output revealed a supplement and sprint interaction effect (P =.009 and P =.049, respectively). Compared with PLA, NaHCO3 + CAF and NaHCO3 increased Wpeak performance in Wt 3 (3%, P =.021) and Wt 4 (4.5%, P =.047), while NaHCO3 supplementation increased mean power performance in Wt 3 (4.2%, P =.001). In Wt 1, CAF increased Wpeak (3.2%, P =.054) and reduced time to Wpeak (−8.5%; P =.008). Plasma lactate showed a supplement plus sprint interaction (P <.001) when NaHCO3 was compared with CAF (13%, P =.031) and PLA (23%, P =.021). Conclusion: To summarize, although the isolated ingestion of CAF and NaHCO3 improved repeated-sprint performance, the coingestion of both supplements did not stimulate a synergic ergogenic effect. [ABSTRACT FROM AUTHOR]

Purpose: Exercise has transient effects on the immune system that could influence infection risk and tissue recovery after exercise. Little is known about how the menstrual cycle interacts with the immune responses to acute exercise. This exploratory study sought to evaluate the effect of menstrual-cycle phase on peripheral blood mononuclear cell counts before and immediately after a bout of intense aerobic exercise. Methods: Seven naturally menstruating women (age: 27 [3] y) completed three 5-km cycling time trials coinciding with the early-follicular, late-follicular, and mid-luteal stage, confirmed by hormonal measurement. Venous blood samples were taken and examined for the presence of immune cell types using flow cytometry. Results: Reductions in circulating CCR7+CD45RA+ naïve CD4+ T cells, CD4+CD25+ regulatory T cells, and CD56+CD57+ natural killer cells observed during the early-follicular phase were attenuated when exercise was performed during the late-follicular phase. Similarly, reductions in circulating CD56+CD57+ natural killer cells and CD14+TLR4+ monocytes following exercise in the early-follicular phase were abolished when exercise was performed in the midluteal phase. Conclusions: These preliminary findings indicate that the effect of acute high-intensity exercise on immune-cell mobilization and activation varies across the menstrual cycle, potentially impacting the anti-inflammatory effects of regulatory T cells and the cell-mediated effects of both natural killer CD57+ cells and monocytes expressing TLR4. [ABSTRACT FROM AUTHOR]

We investigated fatigue and performance rates as decision-making criteria in pacing control during CrossFit®. Thirteen male regional-level competitors completed conditions of all-out (maximum physical work from beginning to end) and controlled-split (controlled physical work in the first two rounds but maximum work in the third round) pacing throughout the Fight Gone Bad workout separated by one week. We assessed benchmarks, countermovement jumps and ratings of fatigue after each round. Benchmarks were lower in round 1 (99 vs. 114, p <.001) but higher in rounds 2 (98 vs. 80, p <.001) and 3 (97 vs. 80, p <.001) for controlled-split compared with all-out pacing. Reductions in countermovement jumps were higher after rounds 1 (−12.6% vs. 1.6%, p <.001) and 2 (−12.7% vs. −4.0%, p =.014) but similar after round 3 (−13.2% vs. −11.3%, p =.571) for all-out compared with controlled-split pacing. Ratings of fatigue were higher after rounds 1 (7 vs. 5 a.u., p <.001) and 2 (8 vs. 7 a.u, p =.023) but similar after round 3 (9 vs. 9 a.u., p =.737) for all-out compared with controlled-split pacing. During all-out pacing, countermovement jump reductions after round 2 correlated with benchmark drops across rounds 1 and 2 (r =.78, p =.002) and rounds 1 and 3 (r = −.77, p =.002) and with benchmark workout changes between pacing strategies (r = −.58, p =.036), suggesting that the larger the countermovement jump reductions the higher the benchmark drops across rounds and workouts. Therefore, benchmarks, countermovement jumps and ratings of fatigue may assess exercise-induced fatigue as decision-making criteria to improve pacing strategy during workouts performed for as many repetitions as possible. [ABSTRACT FROM AUTHOR]

Hypoxia during supramaximal exercise reduces aerobic metabolism with a compensatory increase in anaerobic metabolism without affecting exercise performance. A similar response is elicited by preexercise voluntary hypocapnic hyperventilation, but it remains unclear whether hypocapnic hyperventilation and hypoxia additively reduce aerobic metabolism and increase anaerobic metabolism during supramaximal exercise. To address that issue, 12 healthy subjects (8 males and 4 females) performed the 30-second Wingate anaerobic test (WAnT) after (1) spontaneous breathing in normoxia (control, ∼21% fraction of inspired O2 [FiO2]), (2) voluntary hypocapnic hyperventilation in normoxia (hypocapnia, ∼21% FiO2), (3) spontaneous breathing in hypoxia (hypoxia, ∼11% FiO2), or (4) voluntary hypocapnic hyperventilation in hypoxia (combined, ∼11% FiO2). Mean power output during the 30-second WAnT was similar among the control (561 [133] W), hypocapnia (563 [140] W), hypoxia (558 [131] W), and combined (560 [133] W) trials (P =.778). Oxygen uptake during the 30-second WAnT was lower in the hypocapnia (1523 [318] mL/min), hypoxia (1567 [300] mL/min), and combined (1203 [318] mL/min) trials than in the control (1935 [250] mL/min) trial, and the uptake in the combined trial was lower than in the hypocapnia or hypoxia trial (all P <.001). Oxygen deficit, an index of anaerobic metabolism, was higher in the hypocapnia (38.4 [7.3] mL/kg), hypoxia (37.8 [6.8] mL/kg), and combined (40.7 [6.9] mL/kg) trials than in the control (35.0 [6.8] mL/kg) trial, and the debt was greater in the combined trial than in the hypocapnia or hypoxia trial (all P <.003). Our results suggest that voluntary hypocapnic hyperventilation and hypoxia additively reduce aerobic metabolism and increase anaerobic metabolism without affecting exercise performance during the 30-second WAnT. [ABSTRACT FROM AUTHOR]

We analysed peak 1-, 2- and 5-min periods and the associated 5-min recovery period in matches from three consecutive seasons in the Danish Superliga. A semi-automatic multicamera system was used to collect high-speed running distance (≥5.5 m/s; HSRD), sprint distance (≥7.0 m/s; SpD) and distance covered during intense acceleration (≥3 m/s2; AccD). Analysis included 479 players and 6042 to 9671 match observations using rolling average. Distances covered per minute during the peak periods were significantly higher than match averages: HSRD (207–772%), SpD (447–1793%), and AccD (383–1096%). Distances covered per min were lower during 1-min recovery periods than match average for HSRD following peak 1-, 2- and 5-min period (29%, 6%, 3%, 2%, 2%; 35%, 11%, 0%, 2%, 3%; and 45%, 29%, 13%, 8%, 4%; p < 0.05, respectively), and for SpD (20%, 3%, 7%, 3% (4% higher in the 5th min); 24%, 12%, 3%, 0%, 7%; and 39%, 29%, 18%, 17%, 12%; p < 0.05, respectively). Opposite, AccD increased in the following 1-min recovery periods following peak 1-, 2- and 5-min periods (68%, 89%, 94%, 88%, 90%; 47%, 86%, 93%, 90%, 88%; 23%, 56%, 76%, 85%, 87%; p < 0.05) compared to match averages. Intensity was higher during shorter periods, whereas performance decrements were largest after longer peak periods for HSRD and SpD, whereas no decrement was observed in AccD. [ABSTRACT FROM AUTHOR]

Purpose: Concentration- and time-dependent effect of lactate on physiological adaptation (i.e., glycolytic adaptation and mitochondrial biogenesis) have been reported. Subtetanic neuromuscular electrical stimulation (NMES) with voluntary exercise (VOLES) can increase blood lactate accumulation. However, whether this is also true that VOLES can enhance the blood lactate accumulation during sprint exercise is unknown. Thus, we investigated whether VOLES before the Wingate test can enhance blood lactate accumulation without compromising Wingate exercise performance. Methods: Fifteen healthy young males (mean [SD], age: 23 [4] years, body mass index: 22.0 [2.1] kg/m2) volunteered. After resting measurement, participants performed a 3-min intervention: VOLES (NMES with free-weight cycling) or voluntary cycling alone, which matched exercise intensity with VOLES (VOL, 43.6 [8.0] watt). Then, they performed the Wingate test with 30 min free-weight cycling recovery. The blood lactate concentration ([La]b) was assessed at the end of resting and intervention, and recovery at 1, 3, 5, 10, 20, and 30 min. Results: [La]b during intervention was higher with VOLES than VOL (P = 0.011). The increase in [La]b after the Wingate test was maintained for longer with VOLES than VOL at 10- and 20-min recovery (P = 0.014 and 0.023, respectively). Based on the Wingate test, peak power, mean power, and the rate of decline were not significantly different between VOLES and VOL (P = 0.184, 0.201, and 0.483, respectively). Conclusion: The combination of subtetanic NMES with voluntary exercise before the Wingate test has the potential to enhance blood lactate accumulation. Importantly, this combined approach does not compromise Wingate exercise performance compared to voluntary exercise alone. [ABSTRACT FROM AUTHOR]

Background: Exercise-induced gastrointestinal syndrome (GIS) has symptoms commonly induced by strenuous sports. The study aimed to determine the effect of dihydromyricetin (DHM) administration on high-intensity exercise (HIE)-induced intestinal barrier dysfunction and the underlying mechanism involved with intestinal intraepithelial lymphocytes (IELs). Methods: The HIE model was established with male C57BL/6 mice using a motorized treadmill for 2 weeks, and DHM was given once a day by oral gavage. After being sacrificed, the small intestines of the mice were removed immediately. Results: We found that DHM administration significantly suppressed HIE-induced intestinal inflammation, improved intestinal barrier integrity, and inhibited a HIE-induced increase in the number of IELs and the frequency of CD8αα+ IELs. Meanwhile, several markers associated with the activation, gut homing and immune functions of CD8αα+ IELs were regulated by DHM. Mechanistically, luciferase reporter assay and molecular docking assay showed DHM could activate the aryl hydrocarbon receptor (AhR). Conclusions: These data indicate that DHM exerts a preventive effect against HIE-induced intestinal barrier dysfunction, which is associated with the modulation of the quantity and phenotype of IELs in the small intestine. The findings provide a foundation to identify novel preventive strategies based on DHM supplementation for HIE-induced GIS. [ABSTRACT FROM AUTHOR]

The favorable risk factor profiles and superb cardiac performance of elite long-distance runners, as well as the anti-aging effects of exercise, have likely contributed to the escalating number of adults worldwide who have embraced the notion that "more exercise is invariably better.≵ Nevertheless, vigorous-to-high-intensity physical activity (PA), particularly when unaccustomed, appears to be a trigger for acute cardiac events in individuals with known or occult atherosclerotic cardiovascular disease or structural cardiovascular abnormalities, most notably, hypertrophic cardiomyopathy. Although regular endurance exercise and moderate-to-vigorous PA provide established cardioprotective benefits, high-volume, high-intensity exercise training regimens appear to induce maladaptive cardiac remodeling in some individuals. These potential adverse cardiac adaptations include accelerated coronary artery calcification (CAC), elevated cardiac biomarker release, myocardial fibrosis, and atrial fibrillation (AF), which may be described by a reverse J-shaped curve. However, the risk for acute cardiovascular events is lower in fit/active persons compared to their unfit/inactive counterparts with the same CAC scores. Similarly, the risk of AF is the highest in habitually sedentary older adults, decreases with light-to-moderate intensity regular PA but increases with high-volume, high-intensity exercise regimens (i.e., reverse J-shaped curve). This review examines these relations and more, with specific reference to the World Health Organization exercise intensity and duration recommendations for optimal health, as well as the thresholds for other research-based exercise metrics, including steps/day and the concept of metabolic equivalents-minutes/week. The primary beneficiaries of exercise training programs and long-term goal training intensities, based on age, sex, and "good≵ fitness, are also discussed. In summary, the benefits of regular moderate-to-vigorous PA and the associated improvements in cardiorespiratory fitness far outweigh the risks for most individuals. [ABSTRACT FROM AUTHOR]

The heart is a highly adaptable organ that responds to changes in functional requirements due to exposure to internal and external stimuli. Physical exercise has unique stimulatory effects on the myocardium in both healthy individuals and those with health disorders, where the effects are primarily determined by the intensity and recovery time of exercise. We investigated the time-dependent effects of different exercise intensities on myocardial transcriptional expression in rats. Moderate intensity exercise induced more differentially expressed genes in the myocardium than high intensity exercise, while 16 differentially expressed genes were down-regulated by moderate intensity exercise but up-regulated by high intensity exercise at 12 h post- exercise. Both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated that moderate intensity exercise specifically regulated gene expression related to heart adaptation, energy metabolism, and oxidative stress, while high intensity exercise specifically regulated gene expression related to immunity, inflammation, and apoptosis. Moreover, there was increased expression of Tbx5, Casq1, Igsf1, and Ddah1 at all time points after moderate intensity exercise, while there was increased expression of Card9 at all time points after high intensity exercise. Our study provides a better understanding of the intensity dependent effects of physical exercise of the molecular mechanisms of cardiac adaptation to physical exercise. [ABSTRACT FROM AUTHOR]

To explore the effect of time of day (TOD) on several components of cognitive performance prior and post to a physically exhaustive task in a sample of adolescent elite athletes. In a counterbalanced and randomized order, fourteen highly trained male karate athletes (17 ± 0.96 years; 1.75 ± 0.07 m; 68.0 ± 9.50 kg; BMI 22.15 ± 0.54 kg.m−2) completed two test sessions at 09h00 and 16h00. Cognitive performance was evaluated before and after the karate specific test (KST). During each session, participants completed the profile of mood state (POMS), simple (SRT) and choice (CRT) reaction times, comparison test (COMT), mental rotation test (MRT), egocentric distance estimation (DE), and the rating of perceived exertion (RPE). KST was not TOD dependent (p >.05, d = 0.33). RPE scores were higher in the afternoon compared to the morning (p <.05, d = 0.68). Before the KST, SRT (p <.01, d = 0.69), CRT (p <.01, d = 0.47), COMT (p <.01, d = 0.62) and MRT (p <.001, d = 0.65) were better in the afternoon than in the morning. However, DE was not affected by the TOD (P >.05). KST improved SRT (p <.01, d = 0.078), CRT (p <.001, d = 0.72), COMT (p <.001, d = 1.31) and MRT (p <.001, d = 0.80) performances only in the morning. Cognitive performances are TOD dependent with higher performances realized in the afternoon. Performing a high intensity exercise in the morning, but not in the afternoon, enhanced several aspects of cognitive performances. The current results indicate that an intensive warm-up could be beneficial when a morning competition requires high cognitive readiness. [ABSTRACT FROM AUTHOR]

The accumulation of lactate in muscle and blood during high-intensity exercise is negatively correlated with the duration exercise can be sustained. Removal of lactate is a key component of acute recovery between consecutive bouts of such exercise. Low-intensity exercise enhances recovery by accelerating lactate turnover in metabolically active tissues, largely mediated by blood flow to these tissues. Therefore, the purpose of this research was to clarify if L-citrulline, a nutritional supplement purported to promote vasodilation via enhanced nitric oxide availability, would augment the removal of blood lactate during active recovery (AR). L-citrulline ingestion will augment the rate of blood lactate concentration decrease during AR, reduce the oxygen-cost of submaximal exercise, and increase time-to-exhaustion and peak oxygen uptake (V̇O2peak) during a test of maximal aerobic power. Healthy university students (five males & five females) participated in this double-blind, randomized, placebo-controlled study. Participants exercised on a cycle ergometer at submaximal steady-state intensities followed by progressively increasing intensity to exhaustion, 10 min of AR, and then supramaximal intensity exercise to exhaustion. Oxygen uptake was measured throughout the trial and blood lactate was sampled repeatedly during AR. The protocol elicited very high peak blood lactate concentrations after exercise (11.3 + 1.3 mmol/L). L-citrulline supplementation did not significantly alter blood lactate kinetics during AR, the oxygen cost of exercise, V̇O2peak, or time-to-exhaustion. Despite a strong theoretical basis by which L-citrulline could augment lactate removal from the blood, L-citrulline supplementation showed no effect as an exercise-recovery supplement. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the efficacy of low‐intensity focused ultrasound (LIFU) treatment on rapid relief of delayed‐onset muscle soreness (DOMS) triggered by high‐intensity exercise. Methods: A total of 16 healthy male college students were randomly divided into two groups: the LIFU group (n = 8) and the Sham group (n = 8). After the exercise protocol, the LIFU group received treatment, which parameters included that the power output was 2.5 W/cm2, the frequency was 1 MHz, and the treating time was 20 minutes. The Sham group was treated with LIFU without energy output. Visual analog scale was used to evaluate the level of DOMS in every participant. The activities of plasma creatine kinase, lactate dehydrogenase, and the plasma concentration were measured by spectrophotometry. Tumor necrosis factor‐α and interleukin‐6 of serum were analyzed by enzyme‐linked immunosorbent assay. Results: The visual analog scale of quadriceps femoris and/or calf muscles in the LIFU group decreased significantly at 24 hours (P < 0.01) and 48 hours (P <.01) after the exercise protocol. Both the accumulation of lactic acid (P <.01) in muscle and the activity of lactate dehydrogenase (P <.01) reduced immediately after LIFU treatment. The activities of tumor necrosis factor‐α and interleukin‐6 24 hours lowered in the LIFU group (P <.01). Conclusions: LIFU treatment could relieve muscle soreness rapidly and effectively in the early stages of DOMS. The application of LIFU may provide a potential strategy for clinical treatment for DOMS. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of different limb blood-flow levels on cycling-performance recovery, blood lactate concentration, and heart rate. Methods: Thirty-three high-intensity intermittent-trained athletes completed two 30-s Wingate anaerobic test sessions, 3 x 30-s (WAnT 1-3) and 1 x 30-s (WAnT 4), on a cycling ergometer. WAnT 1-3 and WAnT 4 were separated by a randomly assigned 24-min recovery intervention selected from among blood-flow restriction, passive rest, placebo stimulation, or neuromuscular electrical-stimulation-induced blood flow. Calf arterial inflow was measured by venous occlusion plethysmography at regular intervals throughout the recovery period. Performance was measured in terms of peak and mean power output during WAnT 1 and WAnT 4. Results: After the recovery interventions, a large (r = .68 [90% CL .42; .83]) and very large (r = .72 (90% CL .49; .86]) positive correlation were observed between the change in calf arterial inflow and the change in mean and peak power output, respectively. Calf arterial inflow was significantly higher during the neuromuscular-electrical-stimulation recovery intervention than with the blood-flow-restriction, passive-rest, and placebo-stimulation interventions (P < .001). This corresponds to the only intervention that allowed performance recovery (P > .05). No recovery effect was linked to heart rate or blood lactate concentration levels. Conclusions: For the first time, these data support the existence of a positive correlation between an increase in blood flow and performance recovery between bouts of high-intensity exercise. As a practical consideration, this effect can be obtained by using neuromuscular electrical stimulation-induced blood flow since this passive, simple strategy could be easily applied during short-term recovery. [ABSTRACT FROM AUTHOR]

We combined game activity analyses with skeletal muscle phenotypes and comprehensive physiological testing to elucidate factors of importance for physical performance in elite women's football. GPS‐data from an experimental game, sprint and endurance testing, and muscle tissue analysis of metabolic enzyme activity, protein expression and fiber type composition were completed for international top‐level women players (n = 20; age; 23 ± 4 yrs, height; 166 ± 10 cm, weight; 60 ± 8 kg; VO2max; 51 ± 6 ml/min/kg). Muscle monocarboxylate transporter 4 (MCT4) protein expression explained 46% of the variance in total game distance, while the ability to maintain high‐intensity running (HIR) during the final 15 min of the game correlated to myosin heavy chain 1 (MHCI) and Na+‐K+ ATPase β1, FXYD1 (phospholemman) and superoxide dismutase 2 (SOD2) protein expression (range: r = 0.51–0.71; all p < 0.05). Total HIR distance correlated with (MHCIIa) protein expression (r = 0.51; p < 0.05), while muscle Na+/H+ exchanger 1 (NHE1) protein explained 36% of the variance in game sprint distance (p < 0.05). Total game accelerations (actions >4 m/s2) correlated with platelet endothelial cell adhesion molecule (PECAM‐1) protein expression (r = 0.51; p < 0.05), while concentric knee flexor strength explained 42–62% of the variance in intense decelerations (>4 m/s2). In conclusion, for elite women players' game endurance performance and resistance to end‐game fatigue were affected by monocarboxylate transporter expression and myosin heavy chain profile. HIR was also correlated to ion transporter expression and muscle antioxidative capacity. Finally, the importance of functional strength and measures of muscle vascularization in relation to total game decelerations and accelerations, respectively, illustrates the complex physiological demands in elite women's football. [ABSTRACT FROM AUTHOR]

Exergames may offer novel opportunities to expand physical activity. Most games, however, only result in low to moderate-intensity activities that are too low to allow relevant physical adjustments. In the present study, the exercise intensity of a new, heart rate controlled, functional fitness game was assessed. 28 subjects (aged 24.8±3.8 yrs; 46% female; BMI 23.2±2.3 kg/m2) were enrolled in this study. VO2max and maximal heart rate (HRmax) were assessed during a maximal graded exercise test on a treadmill and compared with the oxygen consumption (VO2) and heart rate (HR) during a game in the ExerCube. In the ExerCube, the subjects reached a peak HR of 187.43±9.22 bpm, which corresponds to 96.57±3.64% of their HRmax. The mean HR throughout the game was 167.11±10.94 bpm, corresponding to 86.07±4.33% of HRmax. VO2peak reached 41.57±5.09 ml/kg/min during the game in the ExerCube, which corresponds to 84.75±7.52% of VO2max. The mean VO2 consumption during the game reached 32.39±4.04 ml/kg/min, which corresponds to 66.01±5.09% of VO2max. The ExerCube provides a form of vigorous physical exercise. Due to its playful, immersive, and motivating nature, the ExerCube seems to be a promising tool to facilitate physical activity. [ABSTRACT FROM AUTHOR]

Background: chicken meat extract is a popular functional food in Asia. It is rich in the bioactive compounds carnosine and anserine, two histidine-containing dipeptides (HCD). Studies suggest that acute pre-exercise ingestion of chicken extracts has important applications towards exercise performance and fatigue control, but the evidence is equivocal. This study aimed to evaluate the ergogenic potential of the pre-exercise ingestion of a homemade chicken broth (CB) vs a placebo soup on a short-lasting, high-intensity cycling exercise. Methods: fourteen men participated in this double-blind, placebo-controlled, crossover intervention study. Subjects ingested either CB, thereby receiving 46.4 mg/kg body weight of HCD, or a placebo soup (similar in taste without HCD) 40 min before an 8 min cycling time trial (TT) was performed. Venous blood samples were collected at arrival (fasted), before exercise and at 5 min recovery. Plasma HCD were measured with UPLC-MS/MS and glutathione (in red blood cells) was measured through HPLC. Capillary blood samples were collected at different timepoints before and after exercise. Results: a significant improvement (p = 0.033; 5.2%) of the 8 min TT mean power was observed after CB supplementation compared to placebo. Post-exercise plasma carnosine (p < 0.05) and anserine (p < 0.001) was significantly increased after CB supplementation and not following placebo. No significant effect of CB supplementation was observed either on blood glutathione levels, nor on capillary blood analysis. Conclusions: oral CB supplementation improved the 8 min TT performance albeit it did not affect the acid-base balance or oxidative status parameters. Further research should unravel the potential role and mechanisms of HCD, present in CB, in this ergogenic approach. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether gastrointestinal (GI) distress affects the ergogenicity of sodium bicarbonate and whether the degree of alkalemia or other metabolic responses is different between individuals who improve exercise capacity and those who do not. Methods: Twenty-one men completed 2 cycling-capacity tests at 110% of maximum power output. Participants were supplemented with 0.3 g/kg body mass of either placebo (maltodextrin) or sodium bicarbonate (SB). Blood pH, bicarbonate, base excess, and lactate were determined at baseline, preexercise, immediately postexercise, and 5 min postexercise. Results: SB supplementation did not significantly increase total work done (TWD; P = .16, 46.8 ±9.1 vs 45.6 ± 8.4 kJ, d = 0.14), although magnitude-based inferences suggested a 63% likelihood of a positive effect. When data were analyzed without 4 participants who experienced GI discomfort, TWD (P = .01) was significantly improved with SB. Immediately postexercise blood lactate was higher in SB for the individuals who improved but not for those who did not. There were also differences in the preexercise-to-postexercise change in blood pH, bicarbonate, and base excess between individuals who improved and those who did not. Conclusions: SB improved high-intensity-cycling capacity but only with the exclusion of participants experiencing GI discomfort. Differences in blood responses suggest that SB may not be beneficial to all individuals. Magnitude-based inferences suggested that the exercise effects are unlikely to be negative; therefore, individuals should determine whether they respond well to SB supplementation before competition. [ABSTRACT FROM AUTHOR]

The cognitive effects of acute aerobic exercise were investigated in endurance-trained individuals. On two occasions, 21 cyclists; 11 male (VO2max: 57 ± 9 mL·kg−1·min−1) and 10 female (VO2max: 51 ± 9 mL·kg−1·min−1), completed 45 min of fixed, moderate-intensity (discontinuous) cycling followed by an incremental ride to exhaustion. Cognitive function was assessed at Baseline, after 15 and 45 min of exercise (15EX and 45EX) and at Exhaustion using a 4-Choice Reaction Time (CRT) test and the Stroop test (Incongruent and Congruent Reaction Time [RT]). A sham capsule was administered on one occasion to determine whether the cognitive response to exercise was robust to the influence of a placebo. CRT, Congruent RT and Incongruent RT decreased (improved) at 15EX, 45EX and Exhaustion compared to Baseline (p's<0.005). While CRT and Congruent RT were faster at 45EX than 15EX (p's<0.020), Incongruent RT was not (p= 1.000). The sham treatment did not affect cognition. When performed at a moderate-intensity, longer duration exercise (up to 45 min) may improve cognition to a greater extent than shorter duration exercise; however, the magnitude of improvement appears to decrease with increasing task complexity. HI/EE performed following a sustained bout of dehydrating activity may not impair cognition. [ABSTRACT FROM AUTHOR]

Abstract Background There is evidence to suggest that postprandial lipemia are is linked to the impairment of endothelial function, which is characterized by an imbalance between the actions of vasodilators and vasoconstrictors. The aim of this study was to determine the effects of a 12-week high-intensity training (HIT) and moderate continuous training (MCT) protocol on postprandial lipemia, vascular function and arterial stiffness in inactive adults after high-fat meal (HFM) ingestion. Methods A randomized clinical trial was conducted in 20 healthy, inactive adults (31.6 ± 7.1 years). Participants followed the two exercise protocols for 12 weeks. To induce a state of postprandial lipemia (PPL), all subjects received a HFM. Endothelial function was measured using flow-mediated vasodilation (FMD), normalized brachial artery FMD (nFMD), aortic pulse wave velocity (PWV) and augmentation index (AIx). Plasma total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides and glucose were also measured. Results The effects of a HFM were evaluated in a fasted state and 60, 120, 180, and 240 min postprandially. A significant decrease in serum glucose between 0 min (fasted state) and 120 min postprandially was found in the HIT group (P = 0.035). Likewise, FMD (%) was significantly different between the fasted state and 60 min after a HFM in the HIT group (P = 0.042). The total cholesterol response expressed as area under curve (AUC)(0–240) was lower following HIT than following MCT, but no significant differences were observed (8%, P > 0.05). Similarly, triglycerides AUC(0–240) was also lower after HIT compared with MCT, which trended towards significance (24%, P = 0.076). The AUC(0–240) for the glucose response was significantly lower following HIT than MCT (10%, P = 0.008). FMD and nFMD AUC(0–240) were significantly higher following HIT than following MCT (46.9%, P = 0.021 and 67.3%, P = 0.009, respectively). PWV AUC(0–240) did not differ following between the two exercise groups (2.3%, P > 0.05). Conclusions Supervised exercise training mitigates endothelial dysfunction and glucose response induced by PPL. Exercise intensity plays an important role in these protective effects, and medium-term HIT may be more effective than MCT in reducing postprandial glucose levels and attenuating vascular impairment. Trial registration ClinicalTrials.gov ID: NCT02738385 Date of registration: April 14, 2016.

Although systemic sex‐specific differences in cardiovascular responses to exercise are well established, the comparison of sex‐specific cerebrovascular responses to exercise has gone under‐investigated especially, during high intensity exercise. Therefore, our purpose was to compare cerebrovascular responses in males and females throughout a graded exercise test (GXT). Twenty‐six participants (13 Females and 13 Males, 24 ± 4 yrs.) completed a GXT on a recumbent cycle ergometer consisting of 3‐min stages. Each sex completed 50W, 75W, 100W stages. Thereafter, power output increased 30W/stage for females and 40W/stage for males until participants were unable to maintain 60‐80 RPM. The final stage completed by the participant was considered maximum workload(Wmax). Respiratory gases (End‐tidal CO2, EtCO2), middle cerebral artery blood velocity (MCAv), heart rate (HR), non‐invasive mean arterial pressure (MAP), cardiac output (CO), and stroke volume (SV) were continuously recorded on a breath‐by‐breath or beat‐by‐beat basis. Cerebral perfusion pressure, CPP = MAP (0. 7,355 distance from heart‐level to doppler probe) and cerebral vascular conductance index, CVCi = MCAv/CPP 100mmHg were calculated. The change from baseline (Δ) in MCAv was similar between the sexes during the GXT (p =.091, ωp2 = 0.05). However, ΔCPP (p <.001, ωp2 = 0.25) was greater in males at intensities ≥ 80% Wmax and ΔCVCi (p =.005, ωp2 = 0.15) was greater in females at 100% Wmax. Δ End‐tidal CO2 (ΔEtCO2) was not different between the sexes during exercise (p =.606, ωp2 = −0.03). These data suggest there are sex‐specific differences in cerebrovascular control, and these differences may only be identifiable at high and severe intensity exercise. [ABSTRACT FROM AUTHOR]

Introduction: Endogenous brain-derived neurotrophic factor (BDNF) is thought to be protective against the neurodegeneration seen in Parkinson's disease (PD), and is thought to increase during exercise. This has been proposed as a possible mechanism by which exercise improves outcomes for people with PD. We conducted a pilot study to investigate the role of exercise intensity on BDNF levels in people with PD. Methods: Participants of early- to mid-stage disease were recruited from a single PD service in north-east England, UK into two separate studies of exercise in PD, one involving moderate-intensity continuous training (MICT) and one involving high-intensity interval training (HIIT), both had control groups. In both the interventions, participants exercise three times per week for 12 weeks. Blood samples were taken for BDNF analysis at the start and end of the first session and the start and end of the final session, with corresponding samples taken in controls. Results: Data were available for 27 participants (13 intervention, 14 control) in the MICT intervention and 17 (9 intervention, 8 control) in the HIIT intervention. BDNF level did not rise significantly from the start to end of individual sessions. Across the 12 week period, they rose significantly in the HIIT intervention group, but not in controls or the MICT intervention group. Conclusions: High-intensity interval training appears to have a greater impact on BDNF than MICT. Future work should directly compare exercise modalities and investigate the impact of BDNF levels on disease progression and quality of life. [ABSTRACT FROM AUTHOR]

The optimal exercise intensity and modality for maximizing cerebral blood flow (CBF) and hence potential exposure to positive, hemodynamically derived cerebral adaptations is yet to be fully determined. This study compared CBF velocity responses between running and cycling across a range of exercise intensities. Twenty‐six participants (12 females; age: 26 ± 8 years) completed four exercise sessions; two mode‐specific maximal oxygen consumption (VO2max) tests, followed by (order randomized) two incremental exercise protocols (3‐min stages at 35%, 50%, 65%, 80%, 95% VO2max). Continuous measures of middle cerebral artery velocity (MCAv), oxygen consumption, end‐tidal CO2 (PETCO2), and heart rate were obtained. Modality‐specific MCAv changes were observed for the whole group (interaction effect: p =.01). Exercise‐induced increases in MCAvmean during cycling followed an inverted‐U pattern, peaking at 65% VO2max (Δ12 ± 7 cm/s from rest), whereas MCAvmean during running increased linearly up to 95% VO2max (change from rest: Δ12 ± 13 vs. Δ7 ± 8 cm/s for running vs. cycling at 95% VO2max; p =.01). In contrast, both modalities had an inverted‐U pattern for PETCO2 changes, although peaked at different intensities (running: 50% VO2max, Δ6 ± 2 mmHg; cycling: 65% VO2max, Δ7 ± 2 mmHg; interaction effect: p =.01). Further subgroup analysis revealed that the running‐specific linear MCAvmean response was fitness dependent (Fitness*modality*intensity interaction effect: p =.04). Above 65% VO2max, fitter participants (n = 16; male > 45 mL/min/kg and female > 40 mL/min/kg) increased MCAvmean up to 95% VO2max, whereas in unfit participants (n = 7, male < mL/min/kg and female < 35 mL/min/kg) MCAvmean returned toward resting values. Findings demonstrate that modality‐ and fitness‐specific profiles for MCAvmean are seen at exercise intensities exceeding 65% VO2max. [ABSTRACT FROM AUTHOR]

This study examined the acute performance, cardiovascular and local muscular responses to perceived exertion-based high-intensity interval exercise using either double- or single-leg cycling. Fifteen healthy middle-aged adults completed, on separate occasions, ten 30-s double-leg intervals interspersed with 60 s passive recovery and twenty (ten with each leg) 30-s single-leg intervals interspersed with 60 s passive recovery. Impedance cardiography, blood pressure, muscle oxygenation and total haemoglobin content (near-infrared spectroscopy), oxygen consumption and power output were measured throughout each session. Normalised to the lean mass used during each trial, single-leg cycling resulted in lower power output (single-leg: 8.92 ± 1.74 W kg−1 and double-leg: 10.41 ± 3.22 W kg−1; p < 0.05) but greater oxygen consumption (single-leg: 103 ± 11 mL kg−1 min−1 and double-leg: 84 ± 21 mL kg−1 min−1; p < 0.01) and cardiac output (single-leg: 1407 ± 334 mL kg−1 min−1 and double-leg: 850 ± 222 mL kg−1 min−1; p < 0.01), compared with double-leg cycling. Mean arterial pressure (double-leg: 108 ± 11 mmHg and single-leg: 102 ± 10 mmHg), change in total haemoglobin content (double-leg: 8.76 ± 10.65 µM cm s−1 and single-leg: 13.42 ± 4.10 µM cm s−1) and change in tissue oxygenation index (double-leg: −4.51 ± 3.56% and single-leg: −3.97 ± 3.91%) were not different between double-leg and single-leg cycling. When compared to double-leg cycling, single-leg cycling elicited a higher cardiac output relative to the lean mass, but this did not result in greater power output. The dissociation between blood availability and power output is consistent with an ageing model characterised by a decrease in local oxygen delivery and distribution capability. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of supramaximal intermittent exercise on long-term cardiac autonomic activity, inferred from heart rate variability (HRV). Methods: Eleven healthy males performed a series of two consecutive intermittent 15-s runs at 95% VIFT (i.e., speed reached at the end of the 30-15 Intermittent Fitness Test) interspersed with 15 s of active recovery at 45% VIFT until exhaustion. Beat-to-beat intervals were recorded during two consecutive nights (habituation night and 1st night) before, 10 min before and immediately after exercise, as well as 12 h (2nd night) and 36 h (3rd night) after supramaximal intermittent exercise. The HRV indices were calculated from the last 5 mm of resting and recovery periods, and the first 10 mm of the first estimated slow wave sleep period. Results: Immediate post-supramaximal exercise vagal-related HRV indices were significantly lower than immediate pre-supramaximal exercise values (P < .001). Most vagal-related indices were lower during the 2nd night compared with the 1st night (eg, mean RR intervals, P = .03). Compared with the 2nd night, vagal-related HRV indices were significantly higher during the 3rd night. Variables were not different between the 1st and 3rd nights; however, we noted a tendency (adjusted effect size, aES) for an increased normalized high-frequency component (P = .06 and aES = 0.70) and a tendency toward a decreased low-frequency component (P = .06 and aES = 0.74). Conclusion: Results confirm the strong influence of exercise intensity on short- and long-term postexercise heart rate variability recovery and might help explain the high efficiency of supramaximal training for enhancing indices of cardiorespiratory fitness. [ABSTRACT FROM AUTHOR]

Introduction: Regular exercise can reduce the risk of developing cardiovascular disease through risk factor modification, with high-intensity exercise and more recently small muscle mass training providing alternatives to moderate-intensity exercise. Methods: This study randomly assigned 53 healthy middle-age adults (age, 62 ± 6 yr) to complete 24 sessions (8 wk; 3 d·wk−1) of exercise training, using either high-intensity double-leg cycling (n = 17; HITDL), high-intensity single-leg cycling (n = 18; HITSL), or moderate-intensity double-leg cycling (n = 18; MCTDL). Biomarkers of cardiovascular risk (total cholesterol, triglycerides, HDL-c, LDL-c, apo-B48, and glucose), anthropometry measures (body mass, body mass index, waist circumference, and waist-to-hip ratio), resting blood pressure, and aerobic capacity were assessed pre- and postintervention. Results: Total work completed was greater (P < 0.01) in MCTDL (5938 ± 1462 kJ) compared with the HITDL (3462 ± 1063 kJ) and HITSL (4423 ± 1875 kJ). Pre- to posttraining differences were observed for waist-to-hip ratio (0.84 ± 0.09 vs 0.83 ± 0.09; P < 0.01), resting systolic blood pressure (129 ± 11 vs 124 ± 12 mm Hg; P < 0.01), total cholesterol (5.87 ± 1.17 vs 5.55 ± 0.98 mmol·L−1; P < 0.01), and LDL-c (3.70 ± 1.04 vs 3.44 ± 0.84 mmol·L−1; P < 0.01), with no differences between conditions. In addition, aerobic capacity increased after training (22.3 ± 6.4 vs 24.9 ± 7.6 mL·kg−1·min−1; P < 0.01), with no differences between conditions. Conclusion: These findings suggest that all three modes of exercise can be prescribed to achieve cardiovascular risk reduction in an aging population. [ABSTRACT FROM AUTHOR]

The O2-kinetic response to constant work rate exercise provides an insight into the adjustment of systemic oxygen transport and muscle metabolism. Whether O2-kinetics measured in laboratory conditions reflect O2-kinetics in field conditions has not yet been analysed. The aim of this study was to compare O2-kinetics between field and laboratory conditions. Thirteen competitive male cyclists (mean±SD age 23.3±4.1 years; V̇O2peak 68.2±4.7 mL. min−1. kg−1) completed two 6-min severe-intensity trials at 60 and 90 rev. min−1 in both conditions. Power output was measured with an SRM power meter and V̇O2 was measured with a portable gas analyser. The time constant (τ), the time delay (TD) and the amplitude (Amp) were resolved by least square regression, and the V̇O2 slow component (SC) was calculated as the difference between the end-exercise V̇O2 and Amp. To determine differences between the trials, a repeated-measure ANOVA was conducted. The Amp and end-exercise V̇O2 were significantly higher during field cycling whereas the SC were significantly higher during laboratory cycling (all at p<0.001). No significant differences were found for τ (p=0.24). Laboratory measures tend to underestimate the oxygen demand in field cycling. A higher cadence leads to greater oxygen demand in laboratory and field cycling. [ABSTRACT FROM AUTHOR]

The focus of the investigation was to examine the effects of citrulline malate (CM) on muscular fatigue in healthy, recreationally trained participants. Twelve participants (men = 6 and women = 6) (24.1 ± 3.9 years) visited the laboratory on 3 separate days, all separated by 1 week. Each visit consisted of consuming 1 of 3 treatments: placebo, CM (8 g), and control in which no drink mixture was consumed. For each day of testing, participants consumed assigned treatment and performed 1 high-intensity exercise trial consisting of squats, lunge jumps, squat jumps, and lateral jumps. Participants performed the exercises in the listed order, which was designated as 1 round. Each participant performed 3 rounds, with the work-to-rest ratio being 20 seconds of work and 30 seconds of rest. A 1-minute rest was given between rounds. A pre/post-exercise isokinetic leg extension test was performed to measure for peak power, peak torque, and rate of fatigue. In addition, blood lactate was obtained pre/post-exercise. There were no treatment or interaction effects (p > 0.05) for peak torque, peak power, rate of fatigue, or blood lactate accumulation. However, there was a statistical significant decrease from pre/post-exercise for peak torque (p = 0.003), peak power (p = 0.003), and rate of fatigue (p = 0.001). In addition, lactate accumulation did increase significantly from pre/post-exercise (p = 0.0001). Finally, neither total work nor final heart rate was statistically significant between the treatments (p > 0.05). Citrulline malate was not effective in improving performance or alleviating fatigue after a high-intensity exercise session. [ABSTRACT FROM AUTHOR]

The current study examined the effect of acute caffeine ingestion on mean and peak power production during upper body Wingate test (WANT) performance, rating of perceived exertion, readiness to invest effort and cognitive performance. Using a double-blind design, 12 males undertook upper body WANTs, following ingestion of caffeine (5 mg*kg−1) or placebo. Pre-substance ingestion, 60 mins post substance ingestion and post exercise participants completed measures of readiness to invest physical and mental effort and cognitive performance. Peak power was significantly higher (P = .026), fatigue index greater (P = .02) and rating of perceived exertion lower (P = .025) in the presence of caffeine. Readiness to invest physical effort was also higher (P = .016) in the caffeine condition irrespective of time point (pre, 60 mins post ingestion and post exercise). Response accuracy for incongruent trials on the Flanker task was superior in the presence of caffeine (P = .006). There was a significant substance × time interaction for response speed in both congruent and incongruent conditions (both P = .001) whereby response speeds were faster at 60 mins post ingestion and post exercise in the caffeine condition, compared to placebo. This is the first study to examine the effects of caffeine ingestion on this modality of exercise and suggests that caffeine ingestion significantly enhances peak power, readiness to invest physical effort, and cognitive performance during WANT performance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the acute cardiorespiratory as well as muscle and cerebral tissue oxygenation responses to submaximal constant-load (CL) and high-intensity interval (HII) cycling exercise performed in normoxia and in hypoxia at similar intensity, reproducing whole-body endurance exercise training sessions as performed in sedentary and clinical populations.Methods: Healthy subjects performed two CL (30 min, 75% of maximal heart rate, n = 12) and two HII (15 times 1-min high-intensity exercise-1-min passive recovery, n = 12) cycling exercise sessions in normoxia and in hypoxia [mean arterial oxygen saturation 76 ± 1% (clamped) during CL and 77 ± 5% (inspiratory oxygen fraction 0.135) during HII]. Cardiorespiratory and near-infrared spectroscopy parameters as well as the rate of perceived exertion were continuously recorded.Results: Power output was 21 ± 11% and 15% (according to protocol design) lower in hypoxia compared to normoxia during CL and HII exercise sessions, respectively. Heart rate did not differ between normoxic and hypoxic exercise sessions, while minute ventilation was higher in hypoxia during HII exercise only (+ 13 ± 29%, p < 0.05). Quadriceps tissue saturation index did not differ significantly between normoxia and hypoxia (CL 60 ± 8% versus 59 ± 5%; HII 59 ± 10% versus 56 ± 9%; p > 0.05), while prefrontal cortex deoxygenation was significantly greater in hypoxia during both CL (66 ± 4% versus 56 ± 6%) and HII (58 ± 5% versus 55 ± 5%; p < 0.05) sessions. The rate of perceived exertion did not differ between normoxic and hypoxic CL (2.4 ± 1.7 versus 2.9 ± 1.8) and HII (6.9 ± 1.4 versus 7.5 ± 0.8) sessions (p > 0.05).Conclusion: This study indicates that at identical heart rate, reducing arterial oxygen saturation near 75% does not accentuate muscle deoxygenation during both CL and HII exercise sessions compared to normoxia. Hence, within these conditions, larger muscle hypoxic stress should not be expected. [ABSTRACT FROM AUTHOR]

This study compared the responses of two priming exercises of similar fatigue on the adjustment of the oxygen uptake time constant (τV̇O2) in cycling. Ten healthy young adults (25 ± 3 yr) performed: three step transitions from a 20-W baseline to the power output (PO) below the gas exchange threshold (MOD, MODPRE); a 3-min bout (P3MIN) at 90% of peak PO (POpeak), followed by MOD (MOD3MIN); and a 6-min bout (P6MIN) at 80% of POpeak, followed by MOD (MOD6MIN). The O2 supply-to-O2 demand ([HHb]/V̇O2) ratio was calculated for MODPRE, MOD3MIN, and MOD6MIN. Neuromuscular fatigue was measured isometrically pre- and post-priming exercise. Reductions in maximal voluntary contraction (−29 ± 6 vs −34 ± 7%) and high-frequency doublet amplitude (−48 ± 13 vs −43 ± 11%) were not significantly different between P3MIN vs P6MIN, suggesting similar fatigue. τV̇O2 for MOD3MIN and MOD6MIN were similar, being ~25% smaller than MODPRE. The [HHb]/V̇O2 ratio was significantly greater in MODPRE (1.13 ± 0.12) compared to MOD3MIN (1.02 ± 0.04) and MOD6MIN (1.02 ± 0.04). This study showed that priming exercise of shorter duration and higher intensity, was sufficient to accelerate V̇O2 kinetics similarly to that observed subsequent to P6MIN when the muscle fatigue was similar. [ABSTRACT FROM AUTHOR]

Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg−1·min−1; body mass index, 31.8 ± 4.5 kg/m2) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control ( p < 0.05) with no differences between the exercise conditions ( p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the hematological and inflammatory responses to 4 maximal high-intensity protocols, considering energy expenditure in each test. 9 healthy volunteers performed 4 high-intensity exercise tests of short [Wingate (WANT); Repeated-sprints (RSA)] and long durations [Continuous VO2 test (VCONT); intermittent VO2 test (VINT)] in a cycle-ergometer, until exhaustion. Hematological parameters and IL-6, IL-10 and creatine kinase (CK) levels were determined before (PRE), POST, 30 min, 1, 2, 12 and 24 h after the end of the protocols. Additionally, energy expenditure was determined. Leucocytes, erythrocytes and lymphocytes increased at POST and returned to PRE values at 30 min for all protocols. Lymphocytes had a second decreased at 2 h and granulocytes increased at 2 h when compared to PRE. Both variables returned to PRE values between 12-24 h into recovery. The magnitude of response for IL-6 was greater in VINT and for IL-10 in VCONT. There was no association of energy expenditure within each exercise protocol with the pattern of IL-6, IL-10 and CK responses to the exercise protocols. The present finding support that similar responses after continuous or intermittent acute protocols are observed when exercises are performed to volitional failure, regardless of the duration and mode of exercise. [ABSTRACT FROM AUTHOR]

High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity-dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury. [ABSTRACT FROM AUTHOR]

Introduction: Exercise performed with blood flow restriction simultaneously enhances the acute responses to both myogenic and mitochondrial pathways with roles in training adaptation. We investigated isoform-specific gene expression of the peroxisome proliferator-activated receptor gamma coactivator 1 and selected target genes and proteins regulating skeletal muscle training adaptation. Methods: Nine healthy, untrained males participated in a randomized, counterbalanced, crossover design in which each subject completed a bout of low-intensity endurance exercise performed with blood flow restriction (15 min cycling at 40% of ...O2peak, BFR-EE), endurance exercise (30 min cycling at 70% of ...O2peak, EE), or resistance exercise (4 x 10 repetitions of leg press at 70% of one-repetition maximum) separated by at least 1 wk of recovery. A single resting muscle biopsy (vastus lateralis) was obtained 2 wk before the first exercise trial (rest) and 3 h after each bout. Results: Total PGC-1α mRNA abundance, along with all four isoforms, increased above rest with EE only (P < 0.05) being higher than BFR-EE (P < 0.05). PGC-1> 1, 2, and 4 were higher after EE compared with resistance exercise (P < 0.05). EE also increased vascular endothelial growth factor, Hif-1α, and MuRF-1 mRNA abundance above rest (P < 0.05), whereas COXIV mRNA expression increased with EE compared with BFR-EE (P < 0.05). Conclusion: The attenuated expression of all four PGC-1α isoforms when EE is performed with blood flow restriction suggests this type of exercise provides an insufficient stimulus to activate the signaling pathways governing mitochondrial and angiogenesis responses observed with moderate- to high-intensity EE. [ABSTRACT FROM AUTHOR]

The present study aimed to analyze and compare the effects of four different interval-training protocols on aerobic fitness and muscle strength. Thirty-seven subjects (23.8 ± 4 years; 171.7 ± 9.5 cm; 70 ± 11 kg) were assigned to one of four groups: low-intensity interval training with ( BFR, n = 10) or without ( LOW, n = 7) blood flow restriction, high-intensity interval training ( HIT, n = 10), and combined HIT and BFR ( BFR + HIT, n = 10, every session performed 50% as BFR and 50% as HIT). Before and after 4 weeks training (3 days a week), the maximal oxygen uptake ( VO2max), maximal power output ( Pmax), onset blood lactate accumulation ( OBLA), and muscle strength were measured for all subjects. All training groups were able to improve OBLA ( BFR, 16%; HIT, 25%; HIT + BFR, 22%; LOW, 6%), with no difference between groups. However, VO2max and Pmax improved only for BFR (6%, 12%), HIT (9%, 15%) and HIT + BFR (6%, 11%), with no difference between groups. Muscle strength gains were only observed after BFR training (11%). This study demonstrates the advantage of short-term low-intensity interval BFR training as the single mode of training able to simultaneously improve aerobic fitness and muscular strength. [ABSTRACT FROM AUTHOR]

Dietary L-citrulline-malate (CM) consumption has been suggested to improve skeletal muscle metabolism and contractile efficiency, which would be expected to predispose exercising individuals to greater fatigue resistance. The purpose of this study was to examine the effects of CM supplementation on acid-base balance and high-intensity exercise performance. In a double-blind, placebo-controlled, crossover study, 10 well-trained males consumed either 12 g of CM (in 400 ml) or lemon sugar-free cordial (placebo [PL]) 60 minutes before completion of 2 exercise trials. Each trial consisted of subjects performing 10 (x 15 seconds) maximal cycle sprints (with 30-second rest intervals) followed by 5 minutes recovery before completing a cycle time-to-exhaustion test (TTE) at 100% of individual peak power (PP). Significant increases in plasma concentrations of citrulline (8.8-fold), ornithine (3.9-fold), and glutamine (1.3-fold) were observed 60 minutes after supplementation in the CM trial only (p ≤ 0.05) and none of the subjects experienced gastrointestinal side-effects during testing. Significantly higher exercise heart rates were observed in CM condition (vs. PL) although no between trial differences in performance related variables (TTE: [120 ± 61 seconds CM vs. 113 ± 50 seconds PL]), PP or mean power, ([power fatigue index: 36 ± 16% CM vs. 28 ± 18% PL]), subjective rating of perceived exertion or measures of acid-base balance (pH, lactate, bicarbonate, base-excess) were observed (p > 0.05). This study demonstrated that acute supplementation of 12 g CM does not provide acute ergogenic benefits using the protocol implemented in this study in well-trained males. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare heart rate variability (HRV) recovery after two iso-volume (5 km) exercises performed at different intensities. 14 subjects volunteered (25.17±5.08 years; 74.7±6.28kg; 175±0.05cm; 59.56±5.15ml⋅kg-1⋅min-1) and after determination of peak oxygen uptake (VO2Peak) and the speed associated with VO2Peak (sVO2Peak), the subjects completed 2 random experimental trials: high-intensity exercise (HIE - 1:1 at 100% sVO2Peak), and moderate-intensity continuous exercise (MIE - 70% sVO2Peak). HRV and RR intervals were monitored before, during and after the exercise sessions together with, the HRV analysis in the frequency domains (high-frequency - HF: 0.15 to 0.4 Hz and low-frequency - LF: 0.04 to 0.15 Hz components) and the ratio between them (LF/HF). Statistical analysis comparisons between moments and between HIE and MIE were performed using a mixed model. Both exercise sessions modified LFlog, HFlog, and LF/HF (F = 16.54, F = 19.32 and F = 5.17, p<0.05, respectively). A group effect was also found for LFlog(F = 23.91,p<0.05), and HFlog(F = 57.55,p< 0.05). LF/HF returned to resting value 15min after MIE exercise and 20min after HIE exercise. This means that the heavy domain (aerobic and anaerobic threshold) induces dissimilar autonomic modification in physically active subjects. Both HIE and MIE modify HRV, and generally HIE delays parasympathetic autonomic modulation recovery after iso-volume exercise. [ABSTRACT FROM AUTHOR]

Angadi, SS, Bhammar, DM, and Gaesser, GA. Postexercise hypotension after continuous, aerobic interval, and sprint interval exercise. J Strength Cond Res 29(10): 2888-2893, 2015—We examined the effects of 3 exercise bouts, differing markedly in intensity, on postexercise hypotension (PEH). Eleven young adults (age: 24.6 6 3.7 years) completed 4 randomly assigned experimental conditions: (a) control, (b) 30-minute steady-state exercise (SSE) at 75-80% maximum heart rate (HRmax), (4) aerobic interval exercise (AIE): four 4-minute bouts at 90-95% HRmax, separated by 3 minutes of active recovery, and (d) sprint interval exercise (SIE): six 30-second Wingate sprints, separated by 4 minutes of active recovery. Exercise was performed on a cycle ergometer. Blood pressure (BP) was measured before exercise and every 15-minute postexercise for 3 hours. Linear mixed models were used to compare BP between trials. During the 3-hour postexercise, systolic BP (SBP) was lower (p , 0.001) after AIE (118 6 10 mm Hg), SSE (121 6 10 mm Hg), and SIE (121 6 11 mm Hg) compared with control (124 6 8 mm Hg). Diastolic BP (DBP) was also lower (p , 0.001) after AIE (66 6 7 mm Hg), SSE (69 6 6 mm Hg), and SIE (68 6 8 mm Hg) compared with control (71 6 7 mm Hg). Only AIE resulted in sustained (.2 hours) PEH, with SBP (120 6 9 mm Hg) and DBP (68 6 7 mm Hg) during the third-hour postexercise being lower (p # 0.05) than control (124 6 8 and 70 6 7 mm Hg). Although all exercise bouts produced similar reductions in BP at 1-hour postexercise, the duration of PEH was greatest after AIE. [ABSTRACT FROM AUTHOR]

Purpose: The effect of exercise intensity and sex on postprandial risk factors for cardiovascular disease in adolescents is unknown. We examined the effect of a single bout of work-matched high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on postprandial triacylglycerol (TAG) and systolic blood pressure (SBP) in adolescents. Method: Twenty adolescents (10 male, 14.3 ± 0.3 years) completed three 1-day trials: (1) rest (CON); (2) 8 × 1 min cycling at 90 % peak power with 75 s recovery (HIIE); (3) cycling at 90 % of the gas exchange threshold (MIE), 1 h before consuming a high-fat milkshake (1.50 g fat and 80 kJ kg). Postprandial TAG, SBP and fat oxidation were assessed over 4 h Results : Compared to CON, the incremental area under the curve for TAG (IAUC-TAG) was not significantly lowered in HIIE [ P = 0.22, effect size (ES) = 0.24] or MIE ( P = 0.65, ES = 0.04) for boys. For girls, HIIE and MIE lowered IAUC-TAG by 34 % ( P = 0.02, ES = 0.58) and 38 % ( P = 0.09, ES = 0.73), respectively, with no difference between HIIE and MIE ( P = 0.74, ES = 0.14). Changes in TAG were not related to energy expenditure during exercise or postprandial fat oxidation. Postprandial SBP (total-AUC pooled for both sexes) was lower in HIIE compared to CON ( P = 0.01, ES = 0.68) and MIE ( P = 0.02, ES = 0.60), with no difference between MIE and CON ( P = 0.45, ES = 0.14). Conclusion: A single bout of HIIE and MIE, performed 1 h before an HFM, can meaningfully attenuate IAUC-TAG in girls but not boys. Additionally, HIIE, but not MIE, may lower postprandial SBP in normotensive adolescents. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated the impact of low-intensity aerobic active recovery sessions between training runs on blood lactate concentration and fatigue in alpine ski racers. Topics explored include the link between blood lactate clearance and better athletic performance, the active and static recovery sessions performed by study participants, and the statistical analyses of data gathered such as physical performance and perceived fatigue rating.

This study investigated the acute effects of a half-time re-warm up on performance and movement patterns in soccer match play. Using a crossover design, 22 professional male players performed traditional passive rest (CON) or a low-intensity re-warm up (RW) during the half-time period of two soccer matches. Before and after the first half and before the second half, maximal sprint and jump performance were evaluated. Time-motion analysis of the first 15 min of each half was conducted. Sprint and jump performance were reduced (P < 0.05) by 2.6% and 7.6%, respectively, during the half-time period in CON, whereas sprint performance was maintained and the decrement in jump performance (3.1%; P < 0.05) was lower after RW. No significant interaction for high-intensity running was observed, but less defensive high-intensity running was observed after RW than CON (0.14 ± 0.06 vs 0.22 ± 0.07 km; P < 0.01). Moreover, RW had more possession of the ball in the beginning of the second half. In conclusion, traditional passive half-time rest leads to impaired sprint and jump performance during the initial phase of the second half in professional soccer players whereas a re-warm up effectively attenuates such deteriorations. Less defensive high-intensity running and more ball possession were observed after RW, indicating a game advantage at the onset of the second half. [ABSTRACT FROM AUTHOR]

The article presents research on the locomotive activities of and exercise intensity in eight female rugby union players during a game, noting that the players' activities such as standing and running as well as the total distance they covered were analyzed using a global positioning system. The study found that the backs position players covered more total distance than players in the forwards position. It also notes the percentage of match time that players were at their maximum heart rate.

High-intensity intermittent exercise induces physiological adaptations similar to energy-matched continuous exercise, but the comparative appetite and energy balance responses are unknown. Twelve healthy males (mean ± SD: age, 22 ± 3 years; body mass index, 23.7 ± 3.0 kg·m−2; maximum oxygen uptake, 52.4 ± 7.1 mL·kg−1·min−1) completed three 8 h trials (control, steady-state exercise (SSE), high-intensity intermittent exercise (HIIE)) separated by 1 week. Trials commenced upon completion of a standardized breakfast. Exercise was performed from hour 2 to hour 3. In SSE, 60 min of cycling at 59.5% ± 1.6% of maximum oxygen uptake was performed. In HIIE, ten 4-min cycling intervals were completed at 85.8% ± 4.0% of maximum oxygen uptake, with a 2-min rest between each interval. A standardized lunch and an ad libitum afternoon meal were provided at hours 3.75 and 7, respectively. Appetite ratings and peptide YY3-36 concentrations were measured throughout each trial. Appetite was acutely suppressed during exercise, but more so during HIIE ( p < 0.05). Peptide YY3-36 concentrations increased significantly upon cessation of exercise in SSE ( p = 0.002), but were highest in the hours after exercise in HIIE ( p = 0.05). Exercise energy expenditure was not different between HIIE and SSE ( p = 0.649), but perceived exertion was higher in HIIE ( p < 0.0005). Ad libitum energy intake did not differ between trials ( p = 0.833). Therefore, relative energy intake (energy intake minus the net energy expenditure of exercise) was lower in the SSE and HIIE trials than in the control trial (control, 4759 ± 1268 kJ; SSE, 2362 ± 1224 kJ; HIIE, 2523 ± 1402 kJ; p < 0.0005). An acute bout of energy-matched continuous exercise and HIIE were equally effective at inducing an energy deficit without stimulating compensatory increases in appetite. [ABSTRACT FROM AUTHOR]

The article discusses changes in repeated-sprint ability performance in elite handball players following high-intensity, heavy load postactivation potentiation half-squat conditioning exercises. Faster sprint times were found in subjects with prior conditioning exercises than those performing only warm-up exercises, suggesting a relationship between muscular strength and power and sprint performance in high-intensity intermittent sports.

The purpose of this investigation was to compare sexes for time to fatigue at 100% VO2peak in recreationally trained individuals. Ten men (age: 23.4 ± 1.8; height: 177 ± 6.7; body mass: 83.8 ± 11.3; ± SD) and nine women (age: 25.0 ± 2.5; height: 165.6 ± 5.5; body mass: 62.7 ± 6.7) participated in this investigation after providing written consent. One week after assessing VO2peak, subjects exercised on an electrically braked cycle ergometer at 100% of VO2peak until fatigue. The time taken to fatigue was 48.9% longer for men than women (274 ± 13s vs. 184 ± 14s;p< 0.001, for men and women, respectively). When normalized for fat free mass (ffm; s/kg ffm) no significant differences between men and women were observed (3.99 ± 0.21s/kg ffm vs. 3.72 ± 0.28s/kg ffm for men and women, respectively,p = 0.431). The difference in fatigability between the sexes at this exercise intensity is to a large degree related to the difference in fat free mass. [ABSTRACT FROM PUBLISHER]

The Biochemical Evaluation of a Health Intervention Programme (B.E. H.I.P.) investigated the impact of progressive exercise intensity in overweight and obese children. A 5-month prospective randomized crossover design (XA, immediate intervention; OB, control group; XB, delayed intervention, OA, postintervention follow-up) with a 10-week health intervention programme was employed. The intervention utilized a progressive increase in high-intensity exercise (≥75% maximum heart rate) and included 3 nutrition and 2 parent education sessions. Primary analysis was completed with ( i) XA versus OB and ( ii) all intervention participants (collapsed XA and XB = XAXB). Prepubertal overweight and obese male and female children ( n = 27) between 5 and 10 years of age were randomly allocated to XA ( n = 16; 11 females; waist circumference = 80.0 ± 10.6 cm) or OB ( n = 11; 3 females; waist circumference = 76.6 ± 7.5 cm). The primary variables were heart rate and percent fat mass. All variables, including body composition, habitual activity, and serum lipids, were repeatedly measured for up to a maximum of 7 time points. Energy expenditure was quantitatively measured throughout each exercise class ( n = 20). A significantly longer time in the exercise sessions was spent in high-intensity (35.1%-60.0%) versus low- to moderate-intensity (64.9%-40.0%) exercise as the intervention progressed from the first to the last attended exercise class (Fisher exact test, p < 0.0001). The percent fat mass decreased in all intervention participants (-2.2%, p < 0.0001). XA had a greater slope decrease than OB for percent fat mass ( p = 0.00051) and triglycerides ( p = 0.0467). In conclusion, high-intensity exercise, within a comprehensive health programme that includes nutrition education, improved the lipid and physiological health profiles of obese children. [ABSTRACT FROM AUTHOR]