bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Caffeine on Upper-Body Anaerobic Performance in Wrestlers in Simulated Competition-Day Conditions
Authors: Aedma Martin , Timpmann Saima , Ööpik Vahur 
Published: August 2016

Purpose:Peak power (PP) and mean power (MP) attained in upper body sprint performance test are considered important factors for competitive success in wrestling. This study aimed to determine whether acute caffeine ingestion would better maintain PP and MP across a simulated competition day in wrestling.Methods:In a double-blind, counterbalanced, crossover study, 14 trained wrestlers ingested either placebo or 5 mg/kg caffeine and completed four 6-min upper body intermittent sprint performance tests with 30-min recovery periods between consecutive tests. PP and MP were recorded during and blood lactate concentration was measured before and after each test. Ratings of perceived fatigue (RPF) and exertion (RPE) were recorded before and after each test, respectively. Heart rate (HR) was monitored across the whole testing period.Results:Mean power decreased across four tests in both trials (p < .05), but the reduction in PP (from 277.2 ± 34.6 W to 257.3 ± 45.1 W; p < .05) only occurred in caffeine trial. Both pretest blood lactate concentration and HR were higher in caffeine than in placebo trial (p < .05) in the third and fourth tests. No between-trial differences occurred in RPF or RPE.Conclusions:Under simulated competition day conditions mimicking four consecutive wrestling matches, acute caffeine ingestion has a partially detrimental effect on upper body intermittent sprint performance in trained wrestlers. Elevated HR and blood lactate levels observed between tests after caffeine ingestion suggest that caffeine may impair recovery between consecutive maximal efforts.
Muscle Glycogenolysis and Resynthesis in Response to a Half Ironman Triathlon: A Case Study
Authors: Gillum Trevor L. , Dumke Charles L. , Ruby Brent C. 
Published: August 2016

Purpose:To describe the degrees of muscle-glycogen depletion and resynthesis in response to a half Ironman triathlon.Methods:One male subject (38 years of age) completed the Grand Columbian half Ironman triathlon (1.9-km swim, 90-km bike, 21.1-km run, Coulee City, Wash). Three muscle biopsies were obtained from his right vastus lateralis (prerace, immediately postrace, and 4 hours postrace). Prerace and postrace body weight were recorded, in addition to macronutrient consumption before, during, and after the race. Energy expenditure and whole-body substrate oxidation were estimated from linear regression established from laboratory trials (watts and run pace relative to VO2 and VCO2).Results:Body weight decreased 3.8 kg from prerace to postrace. Estimated CHO energy expenditure was 10,003 kJ for the bike segment and 5759 kJ for the run segment of the race. The athlete consumed 308 g of exogenous CHO (liquid and gel; 1.21 g CHO/min) during the race. Muscle glycogen decreased from 227.1 prerace to 38.6 mmol · kg wet weight−1 · h−1 postrace. During the 4 hours postrace, the athlete consumed a mixed diet (471 g CHO, 15 g fat, 64 g protein), which included liquid CHO sources and a meal. The calculated rate of muscle-glycogen resynthesis was 4.1 mmol · kg wet weight−1 · h−1.Conclusion:Completing a half Ironman triathlon depends on a high rate of muscle glycogenolysis, which demonstrates the importance of exogenous carbohydrate intake during the race. In addition, rates of muscle-glycogen resynthesis might be dampened by the eccentric damage resulting from the run portion of the race.
Comparisons Between Twice-Daily and Once-Daily Training Sessions in Male Weight Lifters
Authors: Hartman Michael J. , Clark Brandon , Bemben Debra A. , Kilgore J. Lon , Bemben Michael G. 
Published: August 2016

Context:Many elite athletes use increased daily training frequencies as a means to increase training load without substantial published literature to support this practice.Purpose:To compare the physiological responses to twice- and once-daily training sessions with similar training volumes.Methods:Ten nationally competitive male weightlifters (age 20.5 ± 1.2 y, body mass 92.9 ± 23.6 kg, training history 5.5 ± 1.5 y) were matched on body mass and training experience, then randomly assigned to train either once or twice daily for 3 wk. Isometric knee-extension strength (ISO), muscle cross-sectional area, vertical-jump peak power, resting hormone concentrations, neuromuscular activation (EMG), and weightlifting performance were obtained before and after the experimental training period.Results:All dependent measures before the training intervention were similar for both groups. A 2-way repeated-measures ANOVA did not reveal any significant main effects (group or trial) or interaction effects (group × trial) for any of the dependent variables. There were also no significant group differences when parameters were expressed as percentage change, but the twice-daily training group had a greater percentage change in ISO (+5.1% vs +3.2%), EMG (+20.3% vs +9.1%), testosterone (+10.5% vs +6.4%), and testosterone:cortisol ratio (−10.5% vs +1.3%) than did the once-daily training group.Conclusions:There were no additional benefits from increased daily training frequency in national-level male weightlifters, but the increase in ISO and EMG activity for the twice-daily group might provide some rationale for dividing training load in an attempt to reduce the risk of overtraining.
Effects of Varying Post-Warm-Up Recovery Time on 200-m Time-Trial Swim Performance
Authors: Zochowski Thomas , Johnson Elizabeth , Sleivert Gordon G. 
Published: August 2016

Context:Warm-up before athletic competition might enhance performance by affecting various physiological parameters. There are few quantitative data available on physiological responses to the warm-up, and the data that have been reported are inconclusive. Similarly, it has been suggested that varying the recovery period after a standardized warm-up might affect subsequent performance.Purpose:To determine the effects of varying post-warm-up recovery time on a subsequent 200-m swimming time trial.Methods:Ten national-caliber swimmers (5 male, 5 female) each swam a 1500-m warm-up and performed a 200-m time trial of their specialty stroke after either 10 or 45 min of passive recovery. Subjects completed 1 time trial in each condition separated by 1 wk in a counterbalanced order. Blood lactate and heart rate were measured immediately after warm-up and 3 min before, immediately after, and 3 min after the time trial. Rating of perceived exertion was measured immediately after the warm-up and time trial.Results:Time-trial performance was significantly improved after 10 min as opposed to 45 min recovery (136.80 ± 20.38 s vs 138.69 ± 20.32 s, P < .05). There were no significant differences between conditions for heart rate and blood lactate after the warm-up. Pre-time-trial heart rate, however, was higher in the 10-min than in the 45-min rest condition (109 ± 14 beats/min vs 94 ± 21 beats/min, P < .05).Conclusions:A post-warm-up recovery time of 10 min rather than 45 min is more beneficial to 200-m swimming time-trial performance.
Development of a Repeated-Effort Test for Elite Men’s Volleyball
Authors: Sheppard Jeremy M. , Gabbett Tim , Taylor Kristie-Lee , Dorman Jason , Lebedew Alexis J. , Borgeaud Russell 
Published: August 2016

Purpose:The authors conducted a study to develop a repeated-effort test for international men’s volleyball. The test involved jumping and movement activity that was specific to volleyball, using durations and rest periods that replicated the demands of a match.Methods:A time–motion analysis was performed on a national team and development national team during international matches to determine the demands of competition and thereby form the basis of the rationale in designing the repeated-effort test. An evaluation of the test for reliability and validity in discriminating between elite and sub-elite players was performed.Results:The test jump height and movement-speed test parameters were highly reliable, with findings of high intraclass correlations (ICCs) and low typical errors of measurement (TE; ICC .93 to .95 and %TE 0.54 to 2.44). The national team’s ideal and actual jump height and ideal and actual speeds, mean ± SD, were 336.88 ± 8.31 cm, 329.91 ± 6.70 cm, 6.83 ± 0.34 s, and 7.14 ± 0.34 s, respectively. The development national team’s ideal and actual jump heights and ideal and actual speeds were 330.88 ± 9.09 cm, 323.80 ± 7.74 cm, 7.41 ± 0.56 s, and 7.66 ± 0.56 s, respectively. Probabilities of differences between groups for ideal jump, actual jump, ideal time, and actual time were 82%, 95%, 92%, and 96%, respectively, with a Cohen effect-size statistic supporting large magnitudes (0.69, 0.84, 1.34, and 1.13, respectively).Conclusion:The results of this study demonstrate that the developed test offers a reliable and valid method of assessing repeated-effort ability in volleyball players.
Physiological Responses to Exercise on Different Models of the Concept II Rowing Ergometer
Authors: Vogler Andrew J. , Rice Anthony J. , Withers Robert T. 
Published: August 2016

Purpose:The Concept II model C (IIC) rowing ergometer was replaced by the Concept II model D (IID), but the design modifications of the updated ergometer might alter resistance characteristics and rowing technique, thereby potentially influencing ergometer test results. This study evaluated the physiological response to rowing on the IIC and IID ergometers during a submaximal progressive incremental test and maximal-performance time trial.Methods:Eight national-level rowers completed submaximal and maximal tests on the IIC and IID ergometers separated by 48 to 72 h. Physiological responses and calculated blood lactate thresholds (LT1 and LT2) were compared between ergometer models (IIC vs IID) using standardized drag-factor settings.Results:Power output, oxygen consumption, rowing economy (mL O2 · min−1 · W−1), heart rate, blood lactate concentration, stroke rate, and rating of perceived exertion all displayed similar responses regardless of ergometer model. Calculated physiological values equivalent to LT1 and LT2 were also similar between models, except for blood lactate concentration at LT1, which displayed a small but statistically signifcant difference (P = .02) of 0.2 mmol/L.Conclusions:The physiological response when rowing on IIC and IID ergometers is nearly identical, and testing can therefore be carried out on either ergometer and the results directly compared.
Caffeine, Carbohydrate, and Cooling Use During Prolonged Simulated Tennis
Authors: Hornery Daniel J. , Farrow Damian , Mujika Iñigo , Young Warren B. 
Published: August 2016

Purpose:To determine the effects of prolonged simulated tennis on performance and the ergogenic potential of caffeine, carbohydrates, and cooling.Methods:Twelve highly trained male tennis players (age 18.3 ± 3.0 y, height 178.8 ± 8.5 cm, body mass 73.95 ± 12.30 kg, mean ± SD) performed 4 simulated matches (2 h 40 min) against a ball machine on an indoor hard court. The counterbalanced experimental trials involved caffeine supplementation (3 mg/kg), carbohydrate supplementation (6% solution), precooling and intermittent cooling, and placebo control. Physiological markers (core temperature, heart rate, blood lactate, and blood glucose), subjective responses (ratings of perceived exertion and thermal sensation), stroke velocity and accuracy, serve kinematics, and tennis-specific perceptual skill quantified the efficacy of interventions.Results:Significant effects of time (P < .01) reflected increased physiological demand, reduced serve velocity and ground-stroke velocity and accuracy, and a slowing of the serve racket-arm acceleration phase. Caffeine increased serve velocity (165 ± 15 km/h) in the final set of the match (P = .014) compared with placebo (159 ± 15 km/h, P = .008) and carbohydrate (158 ± 13 km/h, P = .001) conditions. Carbohydrate and cooling conditions afforded physiological advantage (increased blood glucose, P < .01, and reduced preexercise thermal sensation, P < .01) but did not affect performance relative to the placebo condition.Conclusions:Prolonged simulated tennis induced significant decrements in tennis skills. Caffeine supplementation partly attenuated the effects of fatigue and increased serve velocity. In contrast, carbohydrate and cooling strategies had little ergogenic effect on tennis performance.
Physiological and Anthropometric Determinants of Rhythmic Gymnastics Performance
Authors: Douda Helen T. , Toubekis Argyris G. , Avloniti Alexandra A. , Tokmakidis Savvas P. 
Published: August 2016

Purpose:To identify the physiological and anthropometric predictors of rhythmic gymnastics performance, which was defined from the total ranking score of each athlete in a national competition.Methods:Thirty-four rhythmic gymnasts were divided into 2 groups, elite (n = 15) and nonelite (n = 19), and they underwent a battery of anthropometric, physical fitness, and physiological measurements. The principal-components analysis extracted 6 components: anthropometric, flexibility, explosive strength, aerobic capacity, body dimensions, and anaerobic metabolism. These were used in a simultaneous multiple-regression procedure to determine which best explain the variance in rhythmic gymnastics performance.Results:Based on the principal-component analysis, the anthropometric component explained 45% of the total variance, flexibility 12.1%, explosive strength 9.2%, aerobic capacity 7.4%, body dimensions 6.8%, and anaerobic metabolism 4.6%. Components of anthropometric (r = .50) and aerobic capacity (r = .49) were significantly correlated with performance (P < .01). When the multiple-regression model—y = 10.708 + (0.0005121 × VO2 max) + (0.157 × arm span) + (0.814 × midthigh circumference) - (0.293 × body mass)—was applied to elite gymnasts, 92.5% of the variation was explained by VO2max (58.9%), arm span (12%), midthigh circumference (13.1%), and body mass (8.5%).Conclusion:Selected anthropometric characteristics, aerobic power, flexibility, and explosive strength are important determinants of successful performance. These findings might have practical implications for both training and talent identification in rhythmic gymnastics.
Postactivation Potentiation of Force Is Independent of H-Reflex Excitability
Authors: Hodgson Matthew J. , Docherty David , Zehr E. Paul 
Published: August 2016

The contractile history of muscle can potentiate electrically evoked force production. A link to voluntary force production, related in part to an increase in reflex excitability, has been suggested.Purpose:Our purpose was to quantify the effect of postactivation potentiation on voluntary force production and spinal H-reflex excitability during explosive plantar fexion actions.Methods:Plantar flexor twitch torque, soleus H-reflex amplitudes, and the rate of force development of explosive plantar fexion were measured before and after 4 separate conditioning trials (3 × 5 s maximal contractions).Results:Twitch torque and rate of force production during voluntary explosive plantar flexion were significantly increased (P < .05) while H-reflex amplitudes remained unchanged. Although twitch torque was significantly higher after conditioning, leading to a small increase in the rate of voluntary force production, this was unrelated to changes in reflex excitability.Conclusion:We conclude that postactivation potentiation may result in a minor increase in the rate of voluntary isometric force production that is unrelated to neural excitability.
A Comparison of Methods Used for Quantifying Internal Training Load in Women Soccer Players
Authors: Alexiou Helen , Coutts Aaron J. 
Published: August 2016

Purpose:The purpose of this study was to compare the session-RPE method for quantifying internal training load (TL) with various HR-based TL quantification methods in a variety of training modes with women soccer players.Methods:Fifteen elite women soccer players took part in the study (age: 19.3 ± 2.0 y and VO2max: 50.8 ± 2.7 mL·kg−1·min−1). Session-RPE, heart rate, and duration were recorded for 735 individual training sessions and matches over a period of 16 wk. Correlation analysis was used to compare session-RPE TLs with three commonly used HR-based methods for assessing TL.Results:The mean correlation for session-RPE TL with Banister’s TRIMP, LTzone TL and Edwards’s TL were (r = 0.84, 0.83, and 0.85, all P < .01, respectively). Correlations for session-RPE TL and three HR-based methods separated by session type were all significant (all P < .05). The strongest correlations were reported for technical (r = 0.68 to 0.82), conditioning (r = 0.60 to 0.79), and speed sessions (r = 0.61 to 0.79).Conclusion:The session-RPE TL showed a significant correlation with all training types common to soccer. Higher correlations were found with less intermittent, aerobic-based training sessions and suggest that HR-based TLs relate better to session-RPE TLs in less intermittent training activities. These results support previous findings showing that the session-RPE TL compares favorably with HR-based methods for quantifying internal TL in a variety of soccer training activities.
Training Repeated Effort Ability in National Team Male Volleyball Players
Authors: Sheppard Jeremy M. , Gabbett Tim , Borgeaud Russell 
Published: August 2016

Purpose:This case study evaluated the effect of repeated lateral movement and jumping training on repeated effort ability in a group of national team male volleyball players.Methods:Twelve volleyball players were assessed on their volleyball-specific repeated movement and jumping abilities using a volleyball-specific repeated effort test (RET) before and after 12 weeks of training. The athletes performed between 8 and 9 volleyball training sessions per week, with 5 to 6 of these sessions including specific training aimed at improving repeated effort ability. Typically these training sessions involved 8 to 12 repetitions of 2 to 3 block jumps over a 9-m lateral distance (ie, the athletes had to perform jumps and lateral movements, typical of front court play in volleyball). Population-specific repeatability data were used to determine whether any changes that may have occurred in this study were beyond the minimal clinically important difference (MCID) for this testing procedure.Results:Improvements in all variables of the RET were observed for each athlete involved in the study, with a small-to-moderate magnitude observed for the mean changes in each variable (Cohen’s d, 0.21 to 0.59). All of the improvements in the results exceeded the MCID.Conclusions:These findings demonstrate that the RET is sensitive to training-induced changes. Lateral movement speed and repeated lateral movement speed, as well as jumping and repeated jumping ability are trainable qualities in high-performance volleyball players.
Effect of Hydration Status on High-Intensity Rowing Performance and Immune Function
Authors: Penkman Michael A. , Field Catherine J. , Sellar Christopher M. , Harber Vicki J. , Bell Gordon J. 
Published: August 2016

Purpose:This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercis.Methods:Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol.Results:The DR condition resulted in a 3.33 ± 0.14% reduction in body mass (P < .05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P < .05). There were increases in the blood concentration of leukocytes, lymphocytes, lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD3−/16+, CD4+/25+; P < .05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P < .05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P < .05). Whereas most immune measures returned to resting values after 60 min of recovery in both trials, lymphocyte proliferation and the concentrations of CD3+/4+ and CD4+/25+ cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial.Conclusion:The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte, neutrophil, and natural killer (CD3−/16+) cell concentrations after exercise compared with the euhydrated state.
The Effects of High-Intensity Interval Training in Well-Trained Rowers
Authors: Driller Matthew W. , Fell James W. , Gregory John R. , Shing Cecilia M. , Williams Andrew D. 
Published: August 2016

Purpose:Several recent studies have reported substantial performance and physiological gains in well-trained endurance runners, swimmers, and cyclists following a period of high-intensity interval training (HIT). The aim of the current study was to compare traditional rowing training (CT) to HIT in well-trained rowers.Methods:Subjects included 5 male and 5 female rowers (mean ± SD; age = 19 ± 2 y; height = 176 ± 8 cm; mass = 73.7 ± 9.8 kg; Vo2peak = 4.37 ± 1.08 L·min−1). Baseline testing included a 2000-m time trial and a maximal exercise test to determine Vo2peak, 4-min all-out power, and 4 mmol·L−1 blood lactate threshold. Following baseline testing, rowers were randomly allocated to HIT or CT, which they performed seven times over a 4-wk period. The HIT involved 8 × 2.5-min intervals at 90% of the velocity maintained at Vo2peak, with individual recoveries returning to 70% of the subjects’ maximal heart rate between intervals. The CT intensity consisted of workloads corresponding to 2 and 3 mmol·L−1 blood lactate concentrations. On completion of HIT or CT, rowers repeated the testing performed at baseline and were then allocated to the alternative training program and completed a crossover trial.Results:HIT produced greater improvements in 2000-m time (1.9 ± 0.9%; mean ± SD), 2000-m power (5.8 ± 3.0%), and relative Vo2peak (7.0 ± 6.4%) than CT.Conclusion:Four weeks of HIT improves 2000-m time-trial performance and relative Vo2peak in competitive rowers, more than a traditional approach.
Reproducibility of Physiological and Performance Measures from a Squash-Specific Fitness Test
Authors: Wilkinson Michael , Leedale-Brown Damon , Winter Edward M. 
Published: August 2016

Purpose:We examined the reproducibility of performance and physiological responses on a squash-specific incremental test.Methods:Eight trained squash players habituated to procedures with two prior visits performed an incremental squash test to volitional exhaustion on two occasions 7 days apart. Breath-by-breath oxygen uptake ( Vo2) and heart rate were determined continuously using a portable telemetric system. Blood lactate concentration at the end of 4-min stages was assessed to determine lactate threshold. Once threshold was determined, test speed was increased every minute until volitional exhaustion for assessment of maximal oxygen uptake (Vo2max), maximum heart rate (HRmax), and performance time. Economy was taken as the 60-s mean of Vo2 in the final minute of the fourth stage (below lactate threshold for all participants). Typical error of measurement (TEM) with associated 90% confidence intervals, limits of agreement, paired sample t tests, and least products regression were used to assess the reproducibility of scores.Results:Performance time (TEM 27 s, 4%, 90% CI 19 to 49 s) Vo2max (TEM 2.4 mL·kg−1·min−1, 4.7%, 90% CI 1.7 to 4.3 mL·kg−1·min−1), maximum heart rate (TEM 2 beats·min−1, 1.3%, 90% CI 2 to 4 beats·min−1), and economy (TEM 1.6 mL·kg−1·min−1, 4.1%, 90% CI 1.1 to 2.8 mL·kg−1·min−1) were reproducible.Conclusions:The results suggest that endurance performance and physiological responses to a squash-specific fitness test are reproducible.