Effect of ischemic preconditioning on repeated sprint ability in team sport athletes

This study investigated whether ischemic preconditioning (IPC) in a trained population affected repeated sprint performance. A secondary aim was to assess responses according to gender. Sixteen (nine females and seven males) well trained team sport athletes took part in a randomised crossover study design. Participants underwent an IPC and placebo treatment involving three periods of 5 min occlusion applied unilaterally (3 × 5 min occlusion to each leg) at either 220 mmHg or 50 mmHg. Each period of occlusion was followed by 5 min reperfusion. Following treatment 5 × 6 s maximal effort sprints were undertaken on a cycle ergometer against 7.5% body mass, each interspersed by 24 s recovery. Measured parameters included peak power, total power, percentage decrement, post-exercise blood lactate and ratings of perceived exertion. Nor within subject main effect for IPC was observed, neither was there an interaction effect with gender. Effect sizes were trivial (ES < 0.2) with the exception of a moderate (ES < 1.2) change in post-exercise blood lactate in the female cohort (1.6 ± 0.4 mmol^?1 lower following IPC). Results suggest no benefit to team sport players in utilising IPC as a means of enhancing repeated sprint performance. A lower blood lactate response in female participants following IPC may suggest improved blood flow through vasodilation.     

我国优秀男子散打运动员身体功能训练研究

探讨身体功能训练在我国优秀男子散打运动员的应用实践效果,采用随机对照实验设计对我国24名优秀男子散打运动员进行为期16周、每周3次、每次60 min的身体功能训练。结果显示:(1)在基本运动能力方面,实验组在平板支撑、仰卧脚撑瑞士球平板支撑、悬吊侧卧平板支撑(左和右两侧)、单腿站平衡垫、瑞士球静蹲、坐位体前屈7项指标上较对照组有非常显著性改善(P<0.01);(2)在一般运动能力方面,实验组在400 m跑、单足4级跳、立卧撑3项指标上较对照组有显著性提高(P<0.05),在Illinois跑、高翻、卧推、深蹲等4项指标上较对照组有非常显著性提升(P<0.01);(3)在专项运动能力方面,实验组在10 s冲拳、10 s侧踹2项指标上较对照组有显著性提高(P<0.05),在30 s变向击打靶、30 s夹背摔假人、单次鞭腿击打力量、10 s腿法击打力量、10 s拳腿组合击打力量5项指标上较对照组有非常显著性提升(P<0.01)。结果表明:优秀男子散打运动员实验组的身体功能训练方案相对于对照组传统力量训练方案,强化了运动员的核心稳定性,优化了动作模式,加强了核心力量及其传输效率,对发展散打运动员的身体功能效果更佳。     

Acute ingestion of beetroot juice does not improve short-duration repeated sprint running performance in male team sport athletes

ABSTRACT

The effects of acute ingestion of nitrate on short-duration repeated sprint performance (RSP) are unclear. This study investigated the effect of acute ingestion of beetroot juice on a test of RSP in team sport athletes. Sixteen male team sport athletes undertook four trials using a 40 m maximum shuttle run test (MST), which incorporates 10 × 40 m shuttle sprints with 30 s between the start of each sprint. Two familiarisation trials, followed by nitrate-rich beetroot juice (BR; ~6 mmol nitrate) and nitrate-depleted beetroot juice (PLA; ~0.0034 mmol nitrate) trials were completed in a randomised, double-blind manner. Ingestion of beetroot juice 3 h prior to exercise elevated plasma nitrate concentrations ~6-fold in BR (BR, 413 ± 56 μM; PLA, 69 ± 30 μM; P < 0.001). RSP, assessed by sprint performance decrement (S_dec; %), did not differ (P = 0.337) between BR (5.31 ± 2.49%) and PLA (5.71 ± 2.61%). There was no difference between trials for total sprint time (P = 0.806), fastest sprint (P = 0.341), slowest sprint (P = 0.787), or post-exercise blood lactate concentration (BR, 11.8 ± 2.5 mM; PLA, 12.2 ± 2.3 mM; P = 0.109). Therefore, acute ingestion of beetroot juice did not improve a test of short-duration RSP in team sport athletes.     

A modified TRIMP to quantify the in-season training load of team sport players

Abstract

The aims of the study were to modify the training impulse (TRIMP) method of quantifying training load for use with intermittent team sports, and to examine the relationship between this modified TRIMP (TRIMP_MOD) and changes in the physiological profile of team sport players during a competitive season. Eight male field hockey players, participating in the English Premier Division, took part in the study (mean±s: age 26±4 years, body mass 80.8±5.2 kg, stature 1.82±0.04 m). Participants performed three treadmill exercise tests at the start of the competitive season and mid-season: a submaximal test to establish the treadmill speed at a blood lactate concentration of 4 mmol · l^?1; a maximal incremental test to determine maximal oxygen uptake ([Vdot]O_2max) and peak running speed; and an all-out constant-load test to determine time to exhaustion. Heart rate was recorded during all training sessions and match-play, from which TRIMP_MOD was calculated. Mean weekly TRIMP_MOD was correlated with the change in [Vdot]O_2max and treadmill speed at a blood lactate concentration of 4 mmol · l^?1 from the start of to mid-season (P<0.05). The results suggest that TRIMP_MOD is a means of quantifying training load in team sports and can be used to prescribe training for the maintenance or improvement of aerobic fitness during the competitive season.     

Sleep and stress hormone responses to training and competition in elite female athletes

Stress hormone and sleep differences in a competition versus training setting are yet to be evaluated in elite female team-sport athletes. The aim of the current study was to evaluate salivary cortisol and perceptual stress markers during competition and training and to determine the subsequent effects on sleep indices in elite female athletes. Ten elite female netball athletes (mean?±?SD; age: 23?±?6 years) had their sleep monitored on three occasions; following one netball competition match (MATCH), one netball match simulation session (TRAIN), and one rest day (CONTROL). Perceived stress values and salivary cortisol were collected immediately pre- (17:15 pm) and post-session (19:30 pm), and at 22:00 pm. Sleep monitoring was performed using wrist actigraphy assessing total time in bed, total sleep time (TST), efficiency (SE%), latency, sleep onset time and wake time. Cortisol levels were significantly higher (p?p?p?相似文献   

高校短跑运动员的专项技术训练

技术训练在提高高校短跑运动员专项素质与专项成绩过程中起着非常重要的作用。在短跑专项技术训练中应注意以下问题:狠抓短跑途中跑的关键技术——大小腿折叠前摆,正确、合理掌握下压扒地动作,改进后蹬技术,科学地解决形成正确技术与训练强度的矛盾。     

Changes in mechanical properties of sprinting during repeated sprint in elite rugby sevens athletes

This study aimed to analyse fatigue-induced changes in mechanical sprinting properties during a specific repeated-sprint test in elite rugby sevens athletes. Twenty elite rugby sevens players performed ten 40?m sprints on a 30?s cycle with participant’s running back and forth in a marked lane. Radar was used to assess maximal overground sprint performance over each 40?m. Macroscopic mechanical properties (maximal horizontal force (F₀), maximal horizontal power (P_max), maximal ratio of horizontal force (RF_peak), decrease in the ratio of horizontal-to-total force (D_RF), total force and maximal sprinting velocity (v₀)) were drawn from horizontal force velocity relationships, using a validated method applied to the speed–time data. Fatigue-induced changes were analysed comparing the first sprint to an average of 2^nd-4^th, 5^th-7^th and 8^th-10^th. Repeated-sprint ability (RSA) testing induced substantial changes in the maximal velocity component, with a decrease (–15%) in v₀ (effect size (ES)?=?–2.46 to –4.98), and to a lower extent (–5.9%) in the maximal force component F₀ (ES?=?–0.59). D_RF moderately decreased (14%; ES=–0.76–1.11), and RF_peak largely decreased in the later sprints (ES?=?–0.32 to –1.27). Fatigue observed in this RSA test appeared to have a greater effect on the technical ability to produce horizontal force at high velocities, likely due to an alteration in the ability to maintain horizontally oriented force application when velocity increases rather than during the initial acceleration phase, but also the overall force production capacity. The ability to maintain forward-oriented force at high velocities is of central importance for identifying fatigue and monitoring load.     

10 weeks of heavy strength training improves performance-related measurements in elite cyclists

ABSTRACT

Elite cyclists have often a limited period of time available during their short preparation phase to focus on development of maximal strength; therefore, the purpose of the present study was to investigate the effect of 10-week heavy strength training on lean lower-body mass, leg strength, determinants of cycling performance and cycling performance in elite cyclists. Twelve cyclists performed heavy strength training and normal endurance training (E&S) while 8 other cyclists performed normal endurance training only (E). Following the intervention period E&S had a larger increase in maximal isometric half squat, mean power output during a 30-s Wingate sprint (P < 0.05) and a tendency towards larger improvement in power output at 4 mmol ? L^?1 [la^?] than E (P = 0.068). There were no significant difference between E&S and E in changes in 40-min all-out trial (4 ± 6% vs. ?1 ± 6%, respectively, P = 0.13). These beneficial effects may encourage elite cyclists to perform heavy strength training and the short period of only 10 weeks should make it executable even in the compressed training and competition schedule of elite cyclists.     

Prevalence of disordered eating in elite female athletes in team sports in Greece

ABSTRACT

The purpose of the study was to assess (a) the prevalence of disordered eating (DE) in elite female team sports players compared to non-athletes and (b) to compare DE prevalence in elite female players in basketball, volleyball and water polo. One hundred and seventy-five females were recruited (age 23.10?±?5.4, BMI 21.85?±?2.3?kg/m²), 53 were elite basketball players, 42 were elite volleyball players, 34 were elite water polo players and 46 were non-athletes. Participants completed the Eating Disorders Questionnaire (EDE-Q) and a physical activity questionnaire. The EDE-Q incorporates 36 statements which relate to the occurrence and frequency of key behaviours of eating disorders, under the following four subscales: Restraint, eating concern, shape concern and weight concern and a global score of disordered eating. No differences were found in the EDE-Q subscale score and global score between athletes and non-athletes. Only 6.2% of the total number of participants exhibited DE using the global score >2.3. Water polo players had significantly higher scores in the ‘eating concern’ subscale and in the frequency of key behavioural features of DE such as binge eating episodes and objective and subjective bulimic episodes, compared to volleyball and basketball players. In conclusion, team sport elite female players do not exhibit greater prevalence of DE compared to non-athletes. Water polo, a sport that emphasises leanness and control of body weight for international distinctions, is associated with a higher tendency to exhibit DE, when compared to other team sports.     

Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes

Abstract

This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO_2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P < 0.05) HR and training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P < 0.05) improvements in VO_2max were measured for SAND compared to GRASS. These results suggest that substituting sand for grass training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.     

少年武术运动员柔韧性训练的研究

武术运动员的柔韧性是非常重要的，它决定着武术运动员妁成绩好坏以及今后的发展方向。如果柔韧性不够好，掌握动作技能的过程会立即缓慢下来，并变得复杂化，而其中某些对完成比赛动作十分重要的关键技术往往不可能学会。关节灵活性差会限制力量、速度和协调能力的发挥，降低肌肉群内和肌肉群间的协调性，是导致肌肉、韧带损伤的原因之一。     

国家乒乓球女二队体能现状及训练方法研究

运用文献资料法、测试法及数理统计法,对国家乒乓球女二队运动员6项体能指标进行测量分析,并针对其特征提出一些训练方法,以期为乒乓球体能训练提供参考依据。     

Altitude training in endurance running: perceptions of elite athletes and support staff

This study sought to establish perceptions of elite endurance athletes on the role and worth of altitude training. Elite British endurance runners were surveyed to identify the altitude and hypoxic training methods utilised, along with reasons for use, and any situational, cultural and behaviour factors influencing these. Prior to the 2012 Olympics Games, 39 athletes and 20 support staff (coaches/practitioners) completed an internet-based survey to establish differences between current practices and the accepted “best-practice”. Almost all of the athletes (98%) and support staff (95%) surveyed had utilised altitude and hypoxic training, or had advised it to athletes. 75% of athletes believed altitude and hypoxia to be a “very important” factor in their training regime, with 50% of support staff believing the same. Athletes and support staff were in agreement of the methods of altitude training utilised (i.e. 'hypoxic dose’ and strategy), with camps lasting 3–4 weeks at 1,500–2,500 m being the most popular. Athletes and support staff are utilising altitude and hypoxic training methods in a manner agreeing with research-based suggestions. The survey identified a number of specific challenges and priorities, which could provide scope to optimise future altitude training methods for endurance performance in these elite groups.     

国家帆船队男子激光级运动员体能训练及康复训练案例分析

对国家帆船队男子激光级两名重点运动员的研究发现,施某主要存在核心力量及高强度运动下腿部肌肉耐力不足,而乔某主要是由于腰肌劳损导致在进行高强度运动时出现腰部酸痛、僵硬、腰椎活动度减弱等问题。根据两者的不同状况,针对性的制定各自的训练方案,通过3~4周的训练后,运动员的运动能力及损伤恢复情况均有所改善。通过高水平运动员体能训练计划制定、实施,改善运动员的运动能力,完善有效提高帆船运动员专项体能训练的手段与方法。同时,通过对重点运动员损伤后的康复训练,汲取康复体能训练有效手段,探索运动损伤机制并在训练中积极预防损伤。     

Not quite so fast: effect of training at 90% sprint speed on maximal and repeated-sprint ability in soccer players

Abstract

The aim of the present study was to investigate the effect of training at an intensity eliciting 90% of maximal sprinting speed on maximal and repeated-sprint performance in soccer. It was hypothesised that sprint training at 90% of maximal velocity would improve soccer-related sprinting. Twenty-two junior club-level male and female soccer players (age 17 ± 1 year, body mass 64 ± 8 kg, body height 174 ± 8 cm) completed an intervention study where the training group (TG) replaced one of their weekly soccer training sessions with a repeated-sprint training session performed at 90% of maximal sprint speed, while the control group (CG) completed regular soccer training according to their teams’ original training plans. Countermovement jump, 12 × 20-m repeated-sprint, VO_2max and the Yo-Yo Intermittent Recovery Level 1 test were performed prior to and after a 9-week intervention period. No significant between-group differences were observed for any of the performance indices and effect magnitudes were trivial or small. Before rejecting the hypothesis, we recommend that future studies should perform intervention programmes with either stronger stimulus or at other times during the season where total training load is reduced.     

中美高校运动训练类专业培养方案的比较

采用文献法和访谈法,对中美8所高校运动训练类专业的培养方案进行比较,旨在完善我国高校运动训练专业人才培养方案,为培养适应时代发展和社会需求的运动训练专业人才提供新思路。研究发现,美国高校的培养目标定位更务实,公共必修课的设置更关注人文与科学素养培育,学分修读更强调过程性评价,以及专业实践课采用“早实习、多实习”的方式,对培养过程的严格监控等做法值得借鉴。     

The effect of heavy resistance exercise on repeated sprint performance in youth athletes

This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.     

The effect of periodized resistance training on accelerative sprint performance

The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6–10%). However, both groups increased 0–10 m sprint times (experimental group = 6%; control group = 3%) while 10–20 m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0–10 m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training.     

The influence of sport goggles on visual target detection in female intercollegiate athletes

The aim of this study was to examine the effects of sport goggles on visual target detection in female intercollegiate athletes. Participants were randomly divided into three groups that varied in goggle use (G) or no goggle use (NG) over a total of three 1-min trials during a visual target detection task. The NG-NG-NG group did not wear goggles for any of the trials, whereas the NG-G-NG group wore goggles for the second trial only, and the G-NG-G group wore goggles for the first and third trials. The task consisted of illuminated targets arranged in five concentric rings from central to peripheral visual angles. The effects of sport goggles on response time to detect targets were most evident in the peripheral rings. Those who did not wear sport goggles showed improved performance from the first to second trials. This improvement was impaired, however, in those who wore sport goggles. Moreover, there was a reversal of the performance improvements achieved without goggles in those who wore goggles on the third trial. Together, these findings suggest the sport goggles not only impaired the expected initial performance but also impaired visual target detection after performance improvements were seen. These findings suggest sport goggles may impair detection of peripheral visual stimuli in athletes.     

中国残疾人乒乓球队备战北京残奥会体能训练管窥

采用文献资料法、访谈法等对2008年北京残奥会中国残疾人乒乓球运动员的体能训练方法进行归纳总结,找出残疾人乒乓球运动员体能训练的成功经验与不足,旨在为今后更加科学化的训练提供借鉴。