bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydration Status in Adolescent Judo Athletes Before and After Training in the Heat
Authors: Rivera-Brown Anita M. , De Félix-Dávila Roberto A. 
Published: August 2016

Adolescent judo athletes who train in tropical climates may be in a persistent state of dehydration because they frequently restrict fluids during daily training sessions to maintain or reduce their body weight and are not given enough opportunities to drink.Purpose:Determine the body hydration status of adolescent judo athletes before, immediately after, and 24 h after (24H) a training session and document sweat Na+ loss and symptoms of dehydration.Methods:Body mass and urine color and specific gravity (USG) were measured before, after, and 24 h after a training session in a high-heat-stress environment (29.5 ± 1.0°C; 77.7 ± 6.1% RH) in 24 adolescent athletes. Sweat sodium loss was also determined. A comparison was made between mid-pubertal (MP) and late pubertal (LP) subjects.Results:The majority of the subjects started training with a significant level of dehydration. During the training session, MP subjects lost 1.3 ± 0.8% of their pretraining body mass whereas LP subjects lost 1.9 ± 0.5% (P < .05). Sweat sodium concentration was 44.5 ± 23.3 mmol/L. Fluid intake from a water fountain was minimal. Subjects reported symptoms of dehydration during the session, which in some cases persisted throughout the night and the next day. The 24H USG was 1.028 ± 0.004 and 1.027 ± 0.005 g/mL for MP and LP, respectively.Conclusions:Adolescent judo athletes arrive to practice with a fluid deficit, do not drink enough during training, and experience symptoms of dehydration, which may compromise the quality of training and general well-being.
Complex Interplay Between Determinants of Pacing and Performance During 20-km Cycle Time Trials
Authors: Renfree Andrew , West Julia , Corbett Mark , Rhoden Clare , Gibson Alan St Clair 
Published: August 2016

Purpose:This study examined the determinants of pacing strategy and performance during self-paced maximal exercise.Methods:Eight well-trained cyclists completed two 20-km time trials. Power output, rating of perceived exertion (RPE), positive and negative affect, and iEMG activity of the active musculature were recorded every 0.5 km, confidence in achieving preexercise goals was assessed every 5 km, and blood lactate and pH were measured postexercise. Differences in all parameters were assessed between fastest (FAST) and slowest (SLOW) trials performed.Results:Mean power output was significantly higher during the initial 90% of FAST, but not the final 10%, and blood lactate concentration was significantly higher and pH significantly lower following FAST. Mean iEMG activity was significantly higher throughout SLOW. Rating of perceived exertion was similar throughout both trials, but participants had significantly more positive affect and less negative affect throughout FAST. Participants grew less confident in their ability to achieve their goals throughout SLOW.Conclusions:The results suggest that affect may be the primary psychological regulator of pacing strategy and that higher levels of positivity and lower levels of negativity may have been associated with a more aggressive strategy during FAST. Although the exact mechanisms through which affect acts to influence performance are unclear, it may determine the degree of physiological disruption that can be tolerated, or be reflective of peripheral physiological status in relation to the still to be completed exercise task.
Warm-Up Intensity and Duration’s Effect on Traditional Rowing Time-Trial Performance
Authors: Mujika Iñigo , de Txabarri Rafa González , Maldonado-Martín Sara , Pyne David B. 
Published: August 2016

The warm-up procedure in traditional rowing usually involves continuous low-intensity rowing and short bouts of intense exercise, lasting about 60 min.Purpose:To compare the effects of a traditional and an experimental 30-min warm-up of lower intensity on indoor rowing time-trial performance.Methods:Fourteen highly trained male rowers (age 25.9 ± 5.3 y, height 1.86 ± 0.06 m, mass 80.4 ± 5.2 kg, peak aerobic power 352.0 ± 24.4 W; mean ± SD) performed 2 indoor rowing trials 12 d apart. Rowers were randomly assigned to either LONG or SHORT warm-ups using a crossover design, each followed by a 10-min all-out fixed-seat rowing-ergometer time trial.Results:Mean power output during the time trial was substantially higher after SHORT (322 ± 18 vs 316 ± 17 W), with rowers generating substantially more power in the initial 7.5 min of the time trial after SHORT. LONG elicited substantially higher mean warm-up heart rate than SHORT (134 ± 11 vs 121 ± 13 beats/min), higher pre–time-trial rating of perceived exertion (10.2 ± 1.4 vs 7.6 ± 1.7) and blood lactate (1.7 ± 0.4 mM vs 1.2 ± 0.2 mM), but similar heart rate (100 ± 14 vs 102 ± 9 beats/min). No substantial differences were observed between LONG and SHORT in stroke rate (39.4 ± 2.0 vs 39.4 ± 2.2 strokes/min) or mean heart rate (171 ± 6 vs 171 ± 8 beats/min) during the time trial, nor in blood lactate after it (11.8 ± 2.5 vs 12.1 ± 2.0 mM).Conclusion:A warm-up characterized by lower intensity and shorter duration should elicit less physiological strain and promote substantially higher power production in the initial stages of a rowing time trial.
All for One and One for All! Disparity Between Overall Crew’s and Individual Rowers’ Pacing Strategies During Rowing
Authors: Renfree Andrew , Martin Louise , Richards Ashley , Gibson Alan St Clair 
Published: August 2016

Purpose:This study examined individual contributions to overall pacing strategy during 2- and 5-km rowing trials in a coxless-4 boat.Methods:A crew of 4 male rowers performed maximal-effort on-water trials over 2 and 5 km, and power output during every individual stroke was measured for each crew member. Mean overall boat and individual rower stroke power were calculated for each 25% epoch (25% of total strokes taken), and power for each individual epoch was calculated as a percentage of mean power maintained over the entire distance. The coefficient of variation was used to determine stroke-to-stroke and epoch-to-epoch variability for individual rowers and the overall boat.Results:In both trials, the overall pacing strategy consisted of a high power output in the initial 25% that decreased in the middle 50% and increased again in the final 25%. However, individual rower data indicate wide variation in individual power profiles that did not always mimic the overall boat profile.Conclusions:This study demonstrates that overall boat power profiles during 2- and 5-km rowing trials are similar to velocity profiles previously reported for individual ergometry and on-water racing events. However, this overall profile is achieved despite considerable variation in individual rower profiles. Further research is warranted to determine the mechanisms through which individual contributions to overall pacing strategy are regulated and the effectiveness or otherwise of seemingly disparate individual strategies on overall performance.
Changes of Whole-Body Power, Muscle Function, and Jump Performance With Prolonged Cycling to Exhaustion
Authors: McIntyre Jordan P.R. , Mawston Grant A. , Cairns Simeon P. 
Published: August 2016

Purpose:To quantify how whole-body power, muscle-function, and jump-performance measures change during prolonged cycling and recovery and determine whether there are relationships between the different fatigue measures.Methods:Ten competitive or recreationally active male cyclists underwent repeated 20-min stages of prolonged cycling at 70% VO2peak until exhaustion. Whole-body peak power output (PPO) was assessed using an all-out 30-s sprint 17 min into each cycle stage. Ratings of perceived exertion (RPE) were recorded throughout. Isometric and isokinetic muscle-function tests were made between cycle stages, over ~6 min, and during 30-min recovery. Drop-jump measures were tested at exhaustion and during recovery.Results:PPO initially increased or was maintained in some subjects but fell to 81% of maximum at exhaustion. RPE was near maximal (18.7) at exhaustion, with the time to exhaustion related to the rate of rise of RPE. PPO first started to decline only when RPE exceeded 16 (ie, hard). Peak isometric and concentric isokinetic torque (180°/s) for the quadriceps fell to 86% and 83% of pretest at exhaustion, respectively. In contrast, the peak concentric isokinetic torque (180°/s) of the hamstrings increased by 10% before declining to 93% of maximum. Jump height fell to 92% of pretest at exhaustion and was correlated with the decline in PPO (r = .79). Muscle-function and jump-performance measures did not recover over the 30-min postexercise rest period.Conclusions:At exhaustion, whole-body power, muscle-function, and jump-performance measures had all fallen by 7–19%. PPO and drop-jump decrements were linearly correlated and are appropriate measures of maximal performance.
Cardiorespiratory Responses to the 30-15 Intermittent Ice Test
Authors: Besson Cyril , Buchheit Martin , Praz Manu , Dériaz Olivier , Millet Grégoire P. 
Published: August 2016

Purpose:In this study, the authors compared the cardiorespiratory responses between the 30–15 Intermittent Ice Test (30-15IIT) and the 30–15 Intermittent Fitness Test (30-15IFT) in semiprofessional hockey players.Methods:Ten players (age 24 ± 6 y) from a Swiss League B team performed the 30-15IIT and 30-15IFT in random order (13 ± 4 d between trials). Cardiorespiratory variables were measured with a portable gas analyzer. Ventilatory threshold (VT), respiratory-compensation point (RCP), and maximal speeds were measured for both tests. Peak blood lactate ([Lapeak]) was measured at 1 min postexercise.Results:Compared with 30-15IFT, 30-15IIT peak heart rate (HRpeak; mean ± SD 185 ± 7 vs 189 ± 10 beats/min, P = .02) and peak oxygen consumption (VO2peak; 60 ± 7 vs 62.7 ± 4 mL/min/kg, P = .02) were lower, whereas [Lapeak] was higher (10.9 ± 1 vs 8.6 ± 2 mmol/L, P < .01) for the 30–15IIT. VT and RCP values during the 30-15IIT and 30-15IFT were similar for %HRpeak (76.3% ± 5% vs 75.5% ± 3%, P = .53, and 90.6% ± 3% vs. 89.8% ± 3%, P = .45) and % VO2peak (62.3% ± 5% vs 64.2% ± 6%, P = .46, and 85.9% ± 5% vs 84.0% ± 7%, P = .33). VO2peak (r = .93, P < .001), HRpeak (r = .86, P = .001), and final velocities (r = .69, P = .029) were all largely to almost perfectly correlated.Conclusions:Despite slightly lower maximal cardiorespiratory responses than in the field-running version of the test, the on-ice 30-15IIT is of practical interest since it is a specific maximal test with a higher anaerobic component.
Enhanced Performance With Elastic Resistance During the Eccentric Phase of a Countermovement Jump
Authors: Aboodarda Saied Jalal , Yusof Ashril , Osman N.A. Abu , Thompson Martin W. , Mokhtar A. Halim 
Published: August 2016

Purpose:To identify the effect of additional elastic force on the kinetic and kinematic characteristics, as well as the magnitude of leg stiffness, during the performance of accentuated countermovement jumps (CMJs).Methods:Fifteen trained male subjects performed 3 types of CMJ including free CMJ (FCMJ; ie, body weight), ACMJ-20, and ACMJ-30 (ie, accentuated eccentric CMJ with downward tensile force equivalent to 20% and 30% body mass, respectively). A force platform synchronized with 6 high-speed infrared cameras was used to measure vertical ground-reaction force (VGRF) and displacement.Results:Using downward tensile force during the lowering phase of a CMJ and releasing the bands at the start of the concentric phase increased maximal concentric VGRF (6.34%), power output (23.21%), net impulse (16.65%), and jump height (9.52%) in ACMJ-30 compared with FCMJ (all P < .05). However, no significant difference was observed in the magnitude of leg stiffness between the 3 modes of jump. The results indicate that using downward recoil force of the elastic material during the eccentric phase of a CMJ could be an effective method to enhance jump performance by applying a greater eccentric loading on the parallel and series elastic components coupled with the release of stored elastic energy.Conclusions:The importance of this finding is related to the proposition that power output, net impulse, takeoff velocity, and jump height are the key parameters for successful athletic performance, and any training method that improves impulse and power production may improve sports performance, particularly in jumping aspects of sport.
Heart-Rate Responses by Playing Position During Ball Drills in Basketball
Authors: Delextrat Anne , Kraiem Semah 
Published: August 2016

The physiological load experienced during basketball drills is crucial to understand players’ adaptation to team-sport training and plan physical-conditioning programs.Purpose:To compare mean heart-rate (HRmean) responses by playing position during 2-a-side (2v2) and 3-a-side (3v3) ball drills in male junior basketball players and explore the relationship between HRmean and repeated-sprint ability (RSA).Methods:Thirtyone players volunteered to participate in this study. On separate occasions, they performed 2v2 and 3v3 ball drills and 6 repetitions of shuttle-run sprints of 20 m (10+10 m), departing every 20 s (RSA). Ball drills took place on the full length but only half the width of the court and were three 4-min bouts separated by 1-min rest periods. An analysis of variance (ANOVA) assessed the effect of the number of players on court (2v2 vs 3v3) and playing position (guards vs forwards vs centers) on HRmean, and a Pearson correlation coefficient evaluated the relation between HRmean and RSA.Results:The main results showed greater HRmean in 2v2 than in 3v3 ball drills (P < .001) in all playing positions (90.7% ± 1.3% vs 87.6% ± 3% of HRpeak in guards, 91.3% ± 2.1% vs 87.5% ± 3.7% of HRpeak for forwards, and 88.2% ± 3.5% vs 82.2% ± 5.6% of HRpeak in centers, respectively, for 2v2 and 3v3). In addition, centers were characterized by lower HRmean than guards and forwards in 3v3 only (P = .018).Conclusions:These results suggest that 2v2 drills should be preferred to 3v3 drills for aerobic conditioning, in particular for centers. Finally, RSA does not seem to influence players’ acute responses to ball drills.
Development of a Comprehensive Performance-Testing Protocol for Competitive Surfers
Authors: Sheppard Jeremy M. , Nimphius Sophia , Haff Greg G. , Tran Tai T. , Spiteri Tania , Brooks Hedda , Slater Gary , Newton Robert U. 
Published: August 2016

Purpose:Appropriate and valid testing protocols for evaluating the physical performances of surfing athletes are not well refined. The purpose of this project was to develop, refine, and evaluate a testing protocol for use with elite surfers, including measures of anthropometry, strength and power, and endurance.Methods:After pilot testing and consultation with athletes, coaches, and sport scientists, a specific suite of tests was developed. Forty-four competitive junior surfers (16.2 ± 1.3 y, 166.3 ± 7.3 cm, 57.9 ± 8.5 kg) participated in this study involving a within-day repeated-measures analysis, using an elite junior group of 22 international competitors (EJG), to establish reliability of the measures. To reflect validity of the testing measures, a comparison of performance results was then undertaken between the EJG and an age-matched competitive junior group of 22 nationally competitive surfers (CJG).Results:Percent typical error of measurement (%TEM) for primary variables gained from the assessments ranged from 1.1% to 3.0%, with intraclass correlation coefficients ranging from .96 to .99. One-way analysis of variance revealed that the EJG had lower skinfolds (P = .005, d = 0.9) than the CJG, despite no difference in stature (P = .102) or body mass (P = .827). The EJG were faster in 15-m sprint-paddle velocity (P < .001, d = 1.3) and had higher lower-body isometric peak force (P = .04, d = 0.7) and superior endurance-paddling velocity (P = .008, d = 0.9).Conclusions:The relatively low %TEM of these tests in this population allows for high sensitivity to detect change. The results of this study suggest that competitively superior junior surfers are leaner and possess superior strength, paddling power, and paddling endurance.
Cycling Attributes That Enhance Running Performance After the Cycle Section in Triathlon
Authors: Etxebarria Naroa , Anson Judith M. , Pyne David B. , Ferguson Richard A. 
Published: August 2016

Purpose:To determine how cycling with a variable (triathlon-specific) power distribution affects subsequent running performance and quantify relationships between an individual cycling power profile and running ability after cycling.Methods:Twelve well-trained male triathletes (VO2peak 4.9 ± 0.5 L/min; mass 73.5 ± 7.7 kg; mean ± SD) undertook a cycle VO2peak and maximal aerobic power (MAP) test and a power profile involving 6 maximal efforts (6 s to 10 min). Each subject then performed 2 experimental 1-h cycle trials, both at a mean power of 65% MAP, at either variable power (VAR) ranging from 40% to 140% MAP or constant power (CON) followed by an outdoor 9.3-km time-trial run. Subjects also completed a control 9.3-km run with no preceding exercise.Results:The 9.3-km run time was 42 ± 37 s slower (mean ± 90% confidence limits [CL]) after VAR (35:32 ± 3:18 min:s, mean ± SD) compared with CON cycling (34:50 ± 2:49 min:s). This decrement after VAR appeared primarily in the first half of the run (35 ± 20 s; mean ± 90% CL). Higher blood lactate and rating of perceived exertion after 1 h VAR cycling were moderately correlated (r = .51–.55; ± ~.40) with a larger decrement in run performance. There were no clear associations between the power-profile test and decrement in run time after VAR compared with CON.Conclusions:A highly variable power distribution in cycling is likely to impair 10-km triathlon run performance. Training to lower physiological and perceptual responses during cycling should limit the negative effects on triathlon running.
Training and Competition Workloads and Fatigue Responses of Elite Junior Cricket Players
Authors: McNamara Dean J. , Gabbett Tim J. , Naughton Geraldine , Farhart Patrick , Chapman Paul 
Published: August 2016

Purpose:This study investigated key fatigue and workload variables of cricket fast bowlers and nonfast bowlers during a 7-wk physical-preparation period and 10-d intensified competition period.Methods:Twenty-six elite junior cricketers (mean ± SD age 17.7 ± 1.1 y) were classified as fast bowlers (n = 9) or nonfast bowlers (n = 17). Individual workloads were measured via global positioning system technology, and neuromuscular function (countermovement jump [relative power and flight time]), endocrine (salivary testosterone and cortisol concentrations), and perceptual well-being (soreness, mood, stress, sleep quality, and fatigue) markers were recorded.Results:Fast bowlers performed greater competition total distance (median [interquartile range] 7049 [3962] m vs 5062 [3694] m), including greater distances at low and high speeds, and more accelerations (40 [32] vs 19 [21]) and had a higher player load (912 [481] arbitrary units vs 697 [424] arbitrary units) than nonfast bowlers. Cortisol concentrations were higher in the physical-preparation (mean ± 90% confidence intervals, % likelihood; d = –0.88 ± 0.39, 100%) and competition phases (d = –0.39 ± 0.30, 85%), and testosterone concentrations, lower (d = 0.56 ± 0.29, 98%), in the competition phase in fast bowlers. Perceptual well-being was poorer in nonfast bowlers during competition only (d = 0.36 ± 0.22, 88%). Differences in neuromuscular function between groups were unclear during physical preparation and competition.Conclusions:These findings demonstrate differences in the physical demands of cricket fast bowlers and nonfast bowlers and suggest that these external workloads differentially affect the neuromuscular, endocrine, and perceptual fatigue responses of these players.
Time-on-Pitch or Full-Game GPS Analysis Procedures for Elite Field Hockey?
Authors: White Andrew D. , MacFarlane Niall 
Published: August 2016

Purpose:The current study assessed the impact of full-game (FG) and time-on-pitch (TOP) procedures for global-positioning-system (GPS) analysis on the commonly used markers of physical performance in elite field hockey.Methods:Sixteen international male field hockey players, age 19–30, were studied (yielding 73 player analyses over 8 games). Physical activity was recorded using a 5-Hz GPS.Results:Distance covered, player load, maximum velocity, high-acceleration efforts, and distance covered at specified speed zones were all agreeable for both analysis procedures (P > .05). However, percentage time spent in 0–6 km/h was higher for FG (ES: –21% to –16%; P < .001), whereas the percentage time in all other speed zones (1.67–3.06 m/s, 3.06–4.17 m/s, 4.17–5.28 m/s, and > 6.39 m/s) and relative distance (m/min) were higher for TOP (ES: 8–10%, 2–7%, 2–3%, 1–1%, 0–1%, respectively; P < .001).Conclusions:These data demonstrate that GPS analysis procedures should be appropriate for the nature of the sport being studied. In field hockey, TOP and FG analysis procedures are comparable for distance-related variables but significantly different for time-dependent factors. Using inappropriate analysis procedures can alter the perceived physiological demand of elite field hockey because of “rolling” substitutions. Inaccurate perception of physiological demand could negatively influence training prescription (for both intensity and volume).
The Application of Peer Mentoring to Improve Fitness in Older Adults
Authors: Dorgo Sandor , King George A. , Brickey Gregory D. 
Published: August 2016

Purpose:To investigate the effectiveness of a peer-mentored exercise program, this study compared the program perception, retention and participation rates, and physical improvements of older adults trained by peer mentors (PMs) with those of a group trained by student mentors (SMs).Methods:After a 30-week peer-mentor preparation, 60 older adults (M ± SD age: 68.7 ± 6.1 yr) were recruited and randomly assigned to either the PM or the SM group. Both groups completed an identical 14-week fitness program. Pre- and posttraining assessments of fitness were completed, and the efficacy of the PMs and SMs was surveyed.Results:High retention was observed in both groups, but the SM group had higher participation. Both groups improved their fitness significantly, with no significant posttest differences between the groups in most fitness measures or in program perception rates.Discussion:Findings suggest effectiveness of the peer-mentor model in an older adult exercise program.
Evidence for the Construct Validity of Self-Motivation as a Correlate of Exercise Adherence in French Older Adults
Authors: André Nathalie , Dishman Rod K. 
Published: August 2016

Objectives:Exercise adherence involves a number of sociocognitive factors that influence the adoption and maintenance of regular physical activity. Among traitlike factors, self-motivation is believed to be a unique predictor of persistence during behavior change. The aim of this study was to validate the factor structure of a French version of the Self-Motivation Inventory (SMI) and to provide initial convergent and discriminant evidence for its construct validity as a correlate of exercise adherence.Method:Four hundred seventy-one elderly were recruited and administered the SMI-10. Structural equation modeling tested the relation of SMI-10 scores with exercise adherence in a correlated network that included decisional balance and perceived quality of life.Results:Acceptable evidence was found to support the factor validity and measurement equivalence of the French version of the SMI-10. Moreover, self-motivation was related to exercise adherence independently of decisional balance and perceived quality of life, providing initial evidence for construct validity.