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1.
Parkour is a modern physical activity that consists of using the environment, mostly urban, as a playground of obstacles. The aims of this study were (i) to investigate age, anthropometric and training characteristics of Parkour practitioners, called ‘traceurs’ and (ii) to assess jump performances and muscular characteristics of traceurs, compared to those of gymnasts and power athletes. The mean age of the population of traceurs studied (n?=?130) was 19.4?±?4.3 years, women represented 12.4% of the total field and mean training volume was 8.1?±?0.5?hours/week. Vertical and long jump performances were analysed on smaller samples of participants (four groups, n?=?15 per group); and eccentric (?90°?s?1, ?30°?s?1), concentric (30°?s?1, 90°?s?1) and isometric knee extensors torques were evaluated by means of an isokinetic dynamometer. Traceurs showed greater (P?P?P?P?相似文献   

2.
Purpose: There is an ongoing debate whether highly trained athletes are less responsive to the ergogenic properties of nitrate. We assessed the effects of nitrate supplementation on plasma nitrate and nitrite concentrations and repeated-sprint performance in recreational, competitive and elite sprint athletes. Methods: In a randomized double-blinded cross-over design, recreational cyclists (n?=?20), national talent speed-skaters (n?=?22) and Olympic-level track cyclists (n?=?10) underwent two 6-day supplementation periods; 140?mL/d nitrate-rich (BR; ～800?mg/d) and nitrate-depleted (PLA; ～0.5?mg/d) beetroot juice. Blood samples were collected and three 30-s Wingate tests were performed. Results: Plasma nitrate and nitrite concentrations were higher following BR vs PLA (P?P?>?.10). Peak power over the three Wingates was not different between BR and PLA (1338?±?30 vs 1333?±?30 W; P?=?.62), and there was no interaction between treatment (BR-PLA) and Wingate number (1-2-3; P?=?.48). Likewise, mean power did not differ between BR and PLA (P?=?.86). In contrast, time to peak power improved by ～2.8% following BR vs PLA (P?=?.007). This improvement in BR vs PLA was not different between Wingate 1, 2 and 3. Moreover, the effects of BR vs PLA did not differ between sport levels for any Wingate parameter (all P?>?.30). Conclusion: The plasma and repeated-sprint performance responses to beetroot juice supplementation do not differ between recreational, competitive and elite sprint athletes. Beetroot juice supplementation reduces time to reach peak power, which may improve the capacity to accelerate during high-intensity and sprint tasks in recreational as well as elite athletes.  相似文献   

3.
The aim of this study was to evaluate the reliability of two long jump tasks and their ability to predict 10 m sprint performance in elite adolescent female athletes. Eight junior national-level female track and field athletes completed three standing (SLJ) and reactive long jumps (RLJ) on portable force plates, followed by three 10 m sprints. Intra-class correlation coefficients (ICC) and coefficients of variation (CV) were calculated to examine reliability. Linear regression results identified the best predictor of average and best 10 m sprint time from the jump kinematic and kinetic measures. The ICCs and CVs indicated good reliability for the majority of kinetic measures however, better reliability was reported for the SLJ. The SLJ was a good predictor of best and average 10 m sprint time, with average horizontal power the best predictor of performance (best; R 2 = 0.751, p = 0.003, Standard Error of Estimate (SEE)% = 2.2 average; R 2 = 0.708, p = 0.005, SEE% = 2.5).  相似文献   

4.
To ensure that elite adolescent athletes meet their unique training, growth and maturation demands, it is imperative to have access to valid measures of energy intake. Contemporary methods demand close attention-to-detail, meaning that athletes often do not fully adhere to real-time protocols. This study represents the first investigation of a real-time dietary assessment designed using a comprehensive behaviour change framework (COM-B). In a crossover design, 12 elite adolescent male rugby players recorded their energy intake via an estimated food diary (est-FD) and photography-based mobile assessment (‘Snap-n-Send’), combined with a 24-h dietary recall interview. Two 4-day assessment periods were divided into three separate recording environments: 96?h free-living and researcher-observed; 72?h free-living and 10?h researcher-observed. Assessment periods were one month apart. All foods and beverages were provided and weighed by the research team to quantify actual intakes. ‘Snap-n-Send’ reported a small mean bias for under-reporting across 96?h (?0.75?MJ?day?1; 95% confidence interval [CI] for bias?=??5.7% to ?2.2%, p?<?.001), 72?h (?0.76?MJ?day?1; 95% CI for bias?=??5.6% to ?2.1%, p?=?.004) and 10?h (?0.72?MJ?day?1; 95% CI for bias?=??8.1% to ?0.1%; p?=?.067) environments. The est-FD reported a moderate mean bias for under-reporting across 96?h (?2.89?MJ?day?1; 95% CI for bias?=??17.9% to ?10.2%; p?<?.001), 72?h (?2.88?MJ?day?1; 95% CI for bias?=??17.9% to ?10.1%; p?<?.001) and 10?h (?2.52?MJ?day?1;?26.1% to ?5.3%; p?=?.023) environments. Results evidence the ability of ‘Snap-n-Send’ to accurately assess the diet of elite adolescent athletes, signalling the exciting promise of this comprehensive and theoretical behavioural approach within valid dietary assessment.  相似文献   

5.
Scrummaging is a major component of Rugby Union gameplay. Successful scrummaging is dependent on the coordination of the forward players and the strength of the eight individuals. The study aim was to determine whether individual scrummaging kinetics and other candidate factors associated with scrummaging performance discriminate team scrum performances. Sixteen club-level forwards (stature: 1.80?±?0.1?m; mass: 99.0?±?18.2?kg) were initially divided into two scrummaging packs. A total of 10 various scrum permutations were tested, where players were randomly swapped between the two packs. Winning scrums were determined by two observers on opposite sides of the scrum. Fatigue (100?mm visual analogue scale (VAS)) and scrummaging effort (6–20 rating of perceived exertion (RPE)) were assessed following each scrum contest. Individual scrummaging kinetics were acquired through an instrumented scrum ergometer and muscular power indicated through vertical jump heights. Student’s t-tests were used to differentiate between winning and losing scrum packs. VAS and RPE were assessed using repeated measures ANOVAs. Winning scrum packs had significantly larger combined force magnitudes (p?<?.002), regardless of the player contribution calculations. Additionally, winning packs had less individual movement (p?=?.033) and higher combined vertical jump heights (p?<?.001) but were not significantly heavier (p?=?.759) than losing scrum packs. While perceived VAS and RPE values progressively increased (p?<?.001), no differences in the individual scrum magnitudes were observed between the 1st and 10th scrum (p?=?.418). The results indicated that the combination of individual forces, variation in movement and factors related to scrummaging performance, such as vertical jump height, were associated with team scrummaging success.  相似文献   

6.
Abstract

No published research has assessed sleep patterns of elite rugby union players following match-play. The present study examined sleep patterns of professional rugby union players, prior and post-match-play, to assess the influence of competition. Twenty-eight male rugby union players (24.4?±?2.9 years, 103.9?±?12.2?kg) competed in one of four competitive home matches. Player's sleep behaviours were monitored continuously using an Actiwatch® from two days before the match, until three days post-match. Repeated measures of analysis of variance (ANOVA) showed significant differences across the time points measured for time to bed (F?=?26.425, η2 ?=?0.495, p < .001), get up time (F?=?21.175, η2?=?0.440, p?<?.001), time spent in bed (F?=?10.669, η2?=?0.283, p?<?.001), time asleep (F?=?8.752, η2?=?0.245, p?<?.001) and percentage of time moving (F?=?4.602, η2?=?0.146 p?<?.05). Most notable, post hocs revealed a significant increase for time in bed the night before the match (p?<?.01; 95% CI?=?0?:?10–1?:?28?h; 9.7?±?13.5%) compared with the reference night sleep. Furthermore, time asleep significantly decreased post-match (p?<?.05; 95% CI?=??0:03 to ?1:59?h; ?19.5?±?19.8%) compared to two nights pre-match. Across all time points, sleep latency and efficiency for most players were considered abnormal compared to that expected in normal populations. The results demonstrate that sleep that is deprived post-match may have detrimental effects on the recovery process.  相似文献   

7.
Attenuated performance during intense exercise with limited endogenous carbohydrate (CHO) is well documented. Therefore, this study examined whether caffeine (CAF) mouth rinsing would augment performance during repeated sprint cycling in participants with reduced endogenous CHO. Eight recreationally active males (aged 23?±?2?yr, body mass 84?±?4?kg, stature 178?±?7?cm) participated in this randomized, single-blind, repeated-measures crossover investigation. Following familiarization, participants attended two separate evening glycogen depletion sessions. The following morning, participants completed five, 6?s sprints on a cycle ergometer (separated by 24?s active recovery), with mouth rinsing either (1) a placebo solution or (2) a 2% CAF solution. During a fifth visit, participants completed the sprints without prior glycogen depletion. Repeated-measures ANOVA identified significant main effect of condition (CAF, placebo, and control [P?P?P?P?P?P?相似文献   

8.
During competition, kayak athletes must optimally adapt to environmental factors (e.g. wind, waves) to achieve peak performance. However, the ability to adapt to such perturbations has never been assessed in kayak paddling. Therefore, the aim of the current study was to evaluate the local dynamic stability in sports technique of youth sprint kayak athletes. In a cross-sectional study, 14 healthy male athletes were recruited from an elite youth sprint kayak squad. During an incremental kayak ergometer test, mean power, heart rates and local dynamic technique stability of hands, arms, trunk and paddle were registered and the association with the athletes 2000?m free-water times were estimated using mixed models. The 2000?m free-water performance significantly predicted the paddles (p?=?.037) local dynamic stability whereas no association was found for the trunk or the upper extremity kinematics. In conclusion, kayak athletes with high-performance capability over 2000?m paddling depict high local dynamic technique stability. This emphasizes the importance of a stable technique for advanced kayak skills, especially regarding paddling movements.  相似文献   

9.
Aim: Recent meta-analyses of the literature confirmed the association between the RR+RX genotype of the ACTN3 R577X polymorphism and elite sprint/power athletic status in Europeans but not in Asians and Africans, while the association between the R577X genotype and elite endurance athlete status is less convincing. The aim of the present study was to investigate the association between the ACTN3 R577X genotype and elite athlete status in a large Asian (Japanese) cohort of track and field athletes. Methods: One-thousand fifty-seven Japanese track and field athletes (627 sprint/power athletes and 430 endurance athletes) and 810 Japanese controls were genotyped for the ACTN3 R577X polymorphism (rs1815739) by using the TaqMan® SNP Genotyping Assay. Results: Elite sprint/power athletes had a higher frequency of the RR+RX genotype than the controls (OR: 1.59, 95% CI: 1.16–2.18; P?=?.003). A significant linear correlation was found between the RR?+?RX genotype and athlete status (i.e. regional?P?=?.001 for trend) and long-distance runners (regional: 65%, national: 72%, international: 82%; P?=?.030 for trend). Conclusions: The data obtained for this large Asian (Japanese) cohort of track and field athletes served to confirm the association between the RR?+?RX genotype of the ACTN3 R577X polymorphism and elite sprint/power athlete status and also the association between the ACTN3 RR?+?RX genotype and long-distance running athletic status.  相似文献   

10.
Scientific information about the effects of caffeine intake on combat sport performance is scarce and controversial. The aim of this study was to investigate the effectiveness of caffeine to improve Brazilian Jiu-jitsu (BJJ)-specific muscular performance. Fourteen male and elite BJJ athletes (29.2?±?3.3?years; 71.3?±?9.1?kg) participated in a randomized double-blind, placebo-controlled and crossover experiment. In two different sessions, BJJ athletes ingested 3?mg?kg?1 of caffeine or a placebo. After 60?min, they performed a handgrip maximal force test, a countermovement jump, a maximal static lift test and bench-press tests consisting of one-repetition maximum, power-load, and repetitions to failure. In comparison to the placebo, the ingestion of the caffeine increased: hand grip force in both hands (50.9?±?2.9 vs. 53.3?±?3.1?kg; respectively p?p?=?.02), and time recorded in the maximal static lift test (54.4?±?13.4 vs. 59.2?±?11.9?s; p?p?=?.02), maximal power obtained during the power-load test (750.5?±?154.7 vs. 826.9?±?163.7?W; p?p?=?.04). In conclusion, the pre-exercise ingestion of 3?mg?kg?1 of caffeine increased dynamic and isometric muscular force, power, and endurance strength in elite BJJ athletes. Thus, caffeine might be an effective ergogenic aid to improve physical performance in BJJ.  相似文献   

11.
The aim of this study was to determine the biomechanical parameters that explain ventral start performance in swimming. For this purpose, 13 elite swimmers performed different variants of the ventral start technique. Two-dimensional video analyses of the aerial and underwater phases were used to assess 16 kinematic parameters from the starting signal to 5?m, and an instrumented starting block was used to assess kinetic data. A Lasso regression was used to reduce the number of parameters, providing the main determinants to starting performance, revealing different combinations of key determinants, depending on the variant (r²?≥?0.90), with flight distance being the most relevant to all variants (r?≤??0.80; p?r?=??0.79; p?r?≤?0.61; p?r²?=?0.66) or block time and flight distance (r²?=?0.83). These data provide relevant contributions to the further understanding of the biomechanics of swimming starts as well as insights for performance analysis and targeted interventions to improve athlete performance.  相似文献   

12.
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13.
Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300?mg flat dose; yielding 3–5?mg/kg bodyweight), COF (8.9?g; 303?mg caffeine), or placebo (PLA; 3.8?g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p?=?.04), but not PLA (p?=?.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p?>?.05). There were no sprint?×?treatment interactions for PP or TW (p?>?.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.  相似文献   

14.
The hypothesis, that sailing upwind in wind speeds above 12 knots causes fatigue, which manifests as a reduction in exerted hiking strap force and/or maximal isometric voluntary contraction force (MVC) of the knee extensors, was evaluated. Additionally, it was investigated if a relationship exists between maximal exerted hiking force (hMVC) and sailing performance. In part 1 of the study, 12 national level athletes sailed upwind for 2?×?10?min while hiking strap forces were continuously acquired. Before, in between and after sailing periods, the MVC of the knee extensors was measured. In part 2 of the study, hMVC was measured dry land in a hiking bench and correlated with the overall results at a national championship. Hiking strap force decreased from the first to the last minute in both 10?min sailing periods (430?±?131 vs. 285?±?130?N, P?<?.001 and 369?±?74 vs. 267?±?97 N, P?<?.001, respectively), but MVC was similar before, between and after the two 10?min sailing periods (878?±?215 vs. 852?±?202 vs. 844?±?211 130?N). In part 2, a significant positive correlation (r2?=?0.619, P?<?.01) was observed between hMVC and regatta results. In conclusion, upwind sailing in wind speeds above 12 knots causes sailing-specific fatigue as evidenced by a marked reduction in exerted hiking strap force. However, MVC of the knee extensors was not compromised ～45?s after hiking was terminated. Additionally, sailing performance is related to maximal hiking force.  相似文献   

15.
The athlete’s brain exhibits significant functional adaptations that facilitate visuomotor reaction performance. However, it is currently unclear if the same neurophysiological processes that differentiate athletes from non-athletes also determine performance within a homogeneous group of athletes. This information can provide valuable help for athletes and coaches aiming to optimize existing training regimes. Therefore, this study aimed to identify the neurophysiological correlates of visuomotor reaction performance in a group of skilled athletes. In 36 skilled badminton athletes, electroencephalography (EEG) was used to investigate pattern reversal and motion onset visual-evoked potentials (VEPs) as well as visuomotor reaction time (VMRT) during a simple reaction task. Stimulus-locked and response-locked event-related potentials (ERPs) in visual and motor regions as well as the onset of muscle activation (EMG onset) were determined. Correlation and multiple regression analyses identified the neurophysiological parameters predicting EMG onset and VMRT. For pattern reversal stimuli, the P100 latency and age best predicted EMG onset (r?=?0.43; p =?.003) and VMRT (r?=?0.62; p?=?.001). In the motion onset experiment, EMG onset (r?=?0.80; p r?=?0.78; p?相似文献   

16.
Citrulline-malate (CM) is a precursor to nitric-oxide (NO) in the NO synthase (NOS) pathway and is suggested to increase exercise performance in younger individuals. With age, NO production decreases and augmented NO production may provide beneficial effects on sports performance among masters athletes (MAs). Purpose: To examine the effects of acute CM supplementation on grip strength, vertical power, and anaerobic cycling performance in female, MA tennis players. Methods: Seventeen female MA (51?±?9 years) completed two double-blind, randomized trials consuming CM (12?g dextrose?+?8?g CM) and placebo (PLA) (12?g dextrose). One hour after consumption, subjects completed grip strength, vertical power, and Wingate anaerobic cycling assessments in respective order. Maximal and average grip strength, peak and average vertical power, anaerobic capacity, peak power, explosive power, and ability to sustain anaerobic power were calculated from the tests. Results: When consuming CM, participants exhibited greater maximal (p?=?.042) and average (p?=?.045) grip strength compared to PLA. No differences existed between trials for peak (p?=?.51) or average (p?=?.51) vertical power. For the Wingate, peak power (p?p?p?Conclusions: These data suggest that consuming CM before competition has the potential to improve tennis match-play performance in masters tennis athletes. However, this study utilized a controlled laboratory environment and research evaluating direct application to on-court performance is warranted.  相似文献   

17.
Abstract

This study aimed to understand the kinematic and kinetic differences between two sprint starts: block and split-stance standing. Fourteen sub-elite male sprinters (100 m time: 11.40?±?0.39?s) performed block and split-stance standing starts sprints over 30 m of in-ground force platforms in a randomised order. Independent t-tests and repeated measures mixed model analysis of variance were used to analyse the between-condition variables across conditions, and over four step phases. Block start sprints resulted in significantly (p?<?.05) faster 5 m (5.0%, effect size [ES]?=?0.89) and 10?m (3.5%, ES?=?0.82) times, but no significant differences were found at 20 and 30?m. No significant differences were found in any kinematic measure between starting positions. However, block starts resulted in significantly (p?<?.001) greater propulsive impulses (6.8%, ES?=?1.35) and net anterior-posterior impulses (6.5%, ES?=?1.12) during steps 1–4, compared to the standing start. Block starts enable athletes to produce a greater amount of net anterior-posterior impulse during early accelerated sprinting, resulting in faster times up to 10 m. When seeking to improve initial acceleration performance, practitioners may wish to train athletes from a block start to improve horizontal force production.  相似文献   

18.
Abstract

The effects of environmental and other venue-related factors need to be taken into account when tracking an individual athlete's competitive performance. We report the effects of such factors on the performances of elite male track athletes. Performance times throughout the athletic careers of male track athletes placed in the top 16 of their event in at least one Olympic Games or World Championship between 2000 and 2009 were downloaded from the athletics results database at tilastopaja.org. In the 10 running events (100 m through 10,000 m, including hurdles and steeplechase), there were 619 athletes with 43,999 performances, all with enviromental and venue-related information. Times for a given event were log-transformed to estimate percent effects in a mixed linear model with fixed effects for the environmental and venue-related factors and random effects for within-athlete race-to-race variability and individual athlete performance progression. After adjustment for quadratic trends for year of competition and each athlete's age, the model provided estimates of effects of standard of competition (Olympics and World Championships vs other competitions), altitude (sea level vs ≥ 1000 m), timing method (electronic vs stopwatch), wind speed (greater than vs less than 2 m · s–1), and venue (outdoors vs indoors). Uncertainty in estimates of environmental effects expressed as 99% confidence limits was sufficiently small (at most ±0.9%) for almost all outcomes to be clear when interpreted in relation to smallest important changes (0.3–0.5%). Olympics and World Championships produced substantially faster times for events up to 400 m (0.7–0.8%) but slower times for the 1500 m, 5000 m, and 10,000 m events (0.6%, 1.2%, and 0.2% respectively), presumably reflecting differences in preparation or pacing. Altitude produced substantially faster times in some 100 m, 200 m, 400 m, and hurdle events (0.1–0.5%) but substantially slower times in longer races (1.1–2.4%), reflecting opposing effects of altitude on air resistance and aerobic power. Stopwatch times were faster for sprints (0.3–0.5%) but slower for 1500 m and longer events (0.6–2.1%), possibly because of bias in reaction time and confounding by standard of competition. A typical trailing wind of 2 m · s–1 conferred small benefits (0.5–0.8%) on the three sprint events where wind speed was recorded. Indoor events were consistently slower (1.6–2.3%), a likely consequence of tight bends. In conclusion, use of these environmental and venue-related effects to adjust performances of male track athletes will make comparative assessment of all their performances more meaningful.  相似文献   

19.
Placebo and nocebo effects occur in response to subjective expectations and their subsequent neural actions. Research shows that information shapes expectations that, consequently, influence people’s behaviour. In this study, we examined the effects of a fictive and inert green colour energy drink provided for three groups (n?=?20/group) with different information. The first group was led to expect that the drink augments running performance (positive information), the second group was led to expect that the drink may or may not improve performance (partial-positive information), while the third group was told that earlier research could not demonstrate that the drink improves performance (neutral/control). At baseline, the three groups did not differ in their 200-m sprint performance (p?>?.05). One week later, 20-min immediately after ingesting the drink, all participants again ran 200?m. The positive information group increased its performance by 2.41?s, which was statistically significant (p?<?.001) and also perceived its sprint-time shorter (p?<?.05) than the other two groups. A better performance (0.97?s) that approached but did not reach statistical significance was also noted in the partial-positive information group, and a lesser change (0.72?s) that was statistically not significant was noted in the neutral information control group. These results reveal that drinking an inert liquid, primed with positive information, changes both the actual and the self-perceived time on a 200-m sprint. The current findings also suggest that the level of certainty of the information might be linked to the magnitude of change in performance.  相似文献   

20.
Physiological or performance tests are routinely utilised to assess athletes’ recovery. At present, the ideal tool to assess recovery remains unknown. Therefore, the aim of this systematic review was to examine the change in creatine kinase (CK) and neuromuscular function as measured via a countermovement jump (CMJ) following a match in the contact codes of football. A comprehensive search of databases was undertaken with RevMan (V 5.3) used for statistical analysis. Our results demonstrated that CK pre- versus post-match (standardised mean difference (SMD)?=?0.90, 95% CI?=?0.50 to 1.31, p?p?p?p?=?.03), and pre- versus 24?h post-match (SMD?=??0.80, 95% CI?=??1.31 to ?0.28, p?=?.002) decreased significantly. There was a significant relationship between the change in CK and the change in CMJ PP from immediately pre to immediately post (r?=??0.924, p?=?.025), and between CMJ immediately following a match and 24?h CK change (r?=??0.983, p?=?.017). In conclusion, CK levels increase and performance in the CMJ decreases following a match of a contact code of football. The identification of this relationship may allow coaching staff to implement a standalone measure of recovery.  相似文献   

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