Postural stability,clicker reaction time and bow draw force predict performance in elite recurve archery     

Wayne Spratford  Rhiannon Campbell 《European Journal of Sport Science》2017,17(5):539-545

Recurve archery is an Olympic sport that requires extreme precision, upper body strength and endurance. The purpose of this research was to quantify how postural stability variables both pre- and post-arrow release, draw force, flight time, arrow length and clicker reaction time, collectively, impacted on the performance or scoring outcomes in elite recurve archery athletes. Thirty-nine elite-level recurve archers (23 male and 16 female; mean age?=?24.7?±?7.3 years) from four different countries volunteered to participate in this study prior to competing at a World Cup event. An AMTI force platform (1000Hz) was used to obtain centre of pressure (COP) measurements 1s prior to arrow release and 0.5s post-arrow release. High-speed footage (200Hz) allowed for calculation of arrow flight time and score. Results identified clicker reaction time, draw force and maximum sway speed as the variables that best predicted shot performance. Specifically, reduced clicker reaction time, greater bow draw force and reduced postural sway speed post-arrow release were predictors of higher scoring shots. It is suggested that future research should focus on investigating shoulder muscle tremors at full draw in relation to clicker reaction time, and the effect of upper body strength interventions (specifically targeting the musculature around the shoulder girdle) on performance in recurve archers.  相似文献   

Light-load maximal lifting velocity full squat training program improves important physical and skill characteristics in futsal players     

Julio Torres-Torrelo  Juan José González-Badillo 《Journal of sports sciences》2017,35(10):967-975

This study aimed to compare the effect of 6 weeks of resistance training or combined resistance training and change of direction exercises on physical performance and motor skills in futsal players. Thirty-four futsal players were divided into full squat group (SG, n = 12), combined full squat and change of direction exercises group (S+CDG, n = 12) and control group (CG, n = 10). The resistance training for SG consisted of full squat with low load (~45–58% 1RM) and low volume (4–6 repetitions), whereas the S+CDG performed the same resistance training program combined with loaded change of direction. Sprint time in 10 and 20 m, change of direction test, countermovement vertical jump (CMJ) height, maximal strength and force–velocity relationship in full squat exercise, kicking speed ball (BS_mean) and repeated sprint ability (RSA_mean) were selected as testing variables. Both experimental groups showed significant improvements for CMJ, BS_mean and all strength parameters. Only SG resulted in significant sprint gains, whereas S+CDG also achieved significant improvements in RSA_mean. The CG remained unchanged after training period. No significant differences were found between both experimental groups. These findings suggest that only 12 sessions of either lightweight resistance training alone, lifting the load at maximal intended velocity or combined with change of direction exercises is enough to improve several physical and skills capacities critical to futsal performance in adult players.  相似文献   

Effects of oncoming target velocities on rapid force production and accuracy of force production intensity and timing     

Yoichi Ohta 《Journal of sports sciences》2017,35(23):2304-2312

The present study aimed to clarify the effects of oncoming target velocities on the ability of rapid force production and accuracy and variability of simultaneous control of both force production intensity and timing. Twenty male participants (age: 21.0 ± 1.4 years) performed rapid gripping with a handgrip dynamometer to coincide with the arrival of an oncoming target by using a horizontal electronic trackway. The oncoming target velocities were 4, 8, and 12 m · s^?1, which were randomly produced. The grip force required was 30% of the maximal voluntary contraction. Although the peak force (Pf) and rate of force development (RFD) increased with increasing target velocity, the value of the RFD to Pf ratio was constant across the 3 target velocities. The accuracy of both force production intensity and timing decreased at higher target velocities. Moreover, the intrapersonal variability in temporal parameters was lower in the fast target velocity condition, but constant variability in 3 target velocities was observed in force intensity parameters. These results suggest that oncoming target velocity does not intrinsically affect the ability for rapid force production. However, the oncoming target velocity affects accuracy and variability of force production intensity and timing during rapid force production.  相似文献   

Kinematic and kinetic analysis of overhand,sidearm and underhand lacrosse shot techniques     

Charles A. J. Macaulay  Pro Stergiou  Darren Stefanyshyn  Luciano Tomaghelli 《Journal of sports sciences》2017,35(23):2350-2356

Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (P < 0.001) and underhand (P < 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (P = 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.  相似文献   

Circadian rhythm effect on physical tennis performance in trained male players     

Álvaro López-Samanes  Diego Moreno-Pérez  José L. Maté-Muñoz  Raúl Domínguez  Jesús G. Pallarés  Ricardo Mora-Rodriguez 《Journal of sports sciences》2017,35(21):2121-2128

To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h^?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.  相似文献   

亚运情境下广州民生举措满意度对知觉与凝聚力的中介作用     

张现成  王斌 《上海体育学院学报》2011,35(6)

以广州亚运会为个案.采用自行设计的民生举措知觉和满意度量表及居民凝聚力量表,探讨亚运情境下当地居民对政府民生举措满意度,及其对居民民生举措知觉、居民凝聚力是否具有中介作用.结果显示:当地居民时政府在举办亚运情境下所采取的能源、安全、就业、全民健身、生态环保、民生服务等举措的知觉,显著影响居民凝聚力;由于民生举措满意度的加入使该影响变小或变得不显著.说明民生举措满意度对民生举措知觉与居民凝聚力具有中介作用.  相似文献   

我国高水平短跑运动员途中跑摆动技术的肌肉用力特征     

张杰  吴瑛  康文峰 《上海体育学院学报》2011,(5)

运用表面肌电遥测和高速摄像同步测试方法,揭示我国部分高水平短跑运动员途中跑摆动技术的肌肉用力特征。结果表明:短跑途中跑摆动技术的肌电特征表现为明显的时序性,肌肉间的收缩具有高度协调性。折叠前摆阶段,摆动腿屈髋肌的主要电位活动是在摆动初期:运动员足蹬离地面至(另一腿)垂直支撑时刻前;垂直支撑时刻后,摆动腿股二头肌长头、半腱肌的活动明显,活动时间较长;下压着地阶段,其工作性质由被动拉长转为向心收缩使髋关节伸,同时还作用于膝关节使膝关节屈,神经肌肉活动的机制十分复杂。在专项力量训练实践中,教练员应结合摆动腿髋关节屈伸肌群的发力特点,优选专项力量训练的手段,提高训练效果。  相似文献   

试论保守力具势的证明     

刘晓东  贾正林 《玉溪师范学院学报》1999,(3)

本文借鉴热力学中一种巧妙的证明方法,用直观的物理论证给出了保守力具势的充分性证明,克服了以往在理论力学课程中只有利用复杂的数学工具才能进行充分性证明,学生难以理解的缺点．  相似文献   

少年儿童不同年龄阶段力量训练特点     

邓梅 《河北体育学院学报》1999,(4)

通过对不同年龄阶段的少年儿童的生理特点和进行力量训练的方法进行分析、讨论 ,认为对少年儿童进行科学合理的早期力量训练 ,不但对其健康无害 ,而且还可以使其运动器官达到良好的发育状态。  相似文献   

理性和意志碰撞的体育动力论   总被引：1，自引：0，他引：1       下载免费PDF全文

余良华  缑小燕  徐雄杰 《武汉体育学院学报》2008,42(11):19

在进一步研究体育的本质问题时发现：理性制约意志驱动体育动力来源发生着碰撞,理性不是唯一的,意志也不是唯一的,彼此之间超越一方达到极至,将产生一种失衡状态,客观地存在着控制与反控制的动力平衡点,这个过程被人类社会秩序完整地掌握和调控。表现在：体育意志试图超越理性的界碑,但总是被限制;理性试图超越意志的体育灵魂,也经受到有力的打击;当理性制约意志的体育动力时,也发生着因果关系的转换。  相似文献