沙滩与室内排球扣球起跳阶段力、冲量及功率指标的对比研究

通过对沙滩、室内排球同一上步扣球起跳动作进行运动学、动力学同步数据采集，比较了二的力、冲量及功率等指标，得出如下结论：1)沙滩排球扣球起跳蹬伸阶段下肢肌群爆发力的发挥水平远远低于室内排球，不利于增大蹬伸冲量的积累；2)分析起跳冲量的内部结构发现。沙滩排球扣球起跳的蹬伸冲量远小于室内排球，从而致使沙滩起跳的恢复系数小于室内的；3)沙滩排球起跳的速度力量水平发挥远低于室内排球是在沙滩上起跳效果差的主要影响因素。     

纵跳中关节功率及其与人体疲劳的关系

考察了纵跳中关节功率及其与人体疲劳的关系。 2次纵跳分别在功率自行车上蹬踏 30 s之前和之后进行。纵跳动作用摄像机摄录下来 ,并在运动解析仪上加以分析。纵跳中的地面反力用测力台测量。根据采集的数据计算了关节功率。通过比较 2组数据计算了各关节处关节功率的变化 ,从而得到了对人体疲劳的一种定量描述     

The Effect of Depth Jumps and Weight Training on Leg Strength and Vertical Jump

Abstract

In recent years, a method of plyometrics (exercises that cause a rapid lengthening of a muscle prior to contraction) called depth jumping has become a part of the training routine of many athletes. Two experiments are described in which the effectiveness of the exercises is examined. In Experiment 1, undergraduate students in beginning weight training classes trained with three different jumping programs: (1) maximum vertical jumps, (2) 0.3 m depth jumps, and (3) 0.75 m and 1.10 m depth jumps. In addition, all groups also lifted weights. In Experiment 2, a weight training class and the volleyball team at Brigham Young University-Hawaii were divided into two groups. One group lifted weights and performed 0.75 and 1.10 m depth jumps. The other group only lifted weights. In Experiment 1, the three training programs resulted in increases in one repetition maximum (1 RM) squat strength, isometric knee extension strength, and in vertical jump; however, there were no significant differences between treatments. In Experiment 2, all groups made significant increases in vertical jump, except the group of weight lifters, who did no jumping. It was concluded that depth jumps are effective but not more effective than a regular jumping routine.     

The Reliability and Validity of the Fitjump Photoelectric Cell System for Determining Vertical Jump Height

ABSTRACT

The aim of this investigation was to assess the reliability and validity of the Fitjump system. Fifty-seven participants (age = 22.62 ± 5.24 years, height = 180.69 ± 12.53 cm, body mass = 75.61 ± 9.56 kg) performed three countermovement jump (CMJ) and squat jump (SJ) with a 1-week interval for test and retest reliability. For validity, the participants performed the same jump protocol on the force platform while being simultaneously measured with the Fitjump system. There was excellent test–retest reliability of the Fitjump system for CMJ and SJ with high intraclass correlation coefficient (ICCs) (0.97 and 0.97, respectively), low coefficient variation (CVs) (2.3% and 2.4%, respectively), and low typical error of estimate [(TEE (%)] (4.0% and 4.4%, respectively). For validity, ICCs were extremely high for CMJ and SJ (0.93 and 0.94, respectively), with low TEE (%) (2.9% and 2.0%, respectively). However, Fitjump overestimated jump height for CMJ and SJ (3.54 and 3.37 cm, respectively; p < 0.001) when compared with the force platform. As a conclusion, the Fitjump system demonstrated excellent test–retest reliability and high relationship with a systematic bias for validity. Therefore, the Fitjump system can be used as a portable tool for monitoring vertical jump changes over time, but it should not be used interchangeably with a force platform.     

男子三级跳远专项力量训练与弱爆发力特征的关系

通过对速度和爆发力素质差的三级跳远运动员高春冬采用特定的训练方案进行训练,使其专项成绩1a内提高0．8m,达到15．40m(国家一级运动员)的水平。特定的训练方案是以提高快速跳跃力量、发展退让肌群力量和专项耐力为目标,以不同的手段组合成4套训练方案,其针对性强,效果好。该方案适用于相近水平的三级跳远运动员。     

Using Principal Components Analysis to Identify Individual Differences in Vertical Jump Performance

Purpose: The purpose of this study was to determine the reliability of cardiorespiratory and pelvic kinematic responses to simulated horseback riding (SHBR) and to characterize responses to SHBR relative to walking in apparently healthy children. Method: Fifteen healthy children (M_age = 9.5 ± 2.6 years) completed SHBR on a commercially available simulator at low intensity (0.27 Hz) and high intensity (0.65 Hz) during 3 sessions on different occasions. Heart rate (HR), blood pressure, and respiratory gases were measured at rest and during steady-state exercise at both intensities. Pelvic displacement was measured during steady-state exercise. Rate of energy expenditure, mean arterial pressure, and rate pressure product (RPP) were calculated. Participants also walked on a treadmill for 26.8 m/min to 80.5 m/min in 13.4-m/min increments at 0% grade during 1 session to compare cardiorespiratory responses with those of SHBR. Results: Physiological variables across all 3 SHBR sessions were similar at both intensities (p>.05 for all). Intraclass correlation coefficients (ICCs) and coefficients of variation indicate good to modest reliability of cardiorespiratory measures during SHBR (ICCs = .542–.996 for oxygen consumption, energy expenditure, and RPP). Cardiorespiratory variables, except for HR, were 2% to 19% greater, and pelvic displacement was up to 37% greater with high-intensity riding. Treadmill walking at all speeds elicited greater physiological responses compared with SHBR (p < .05). Conclusion: Cardiorespiratory responses and pelvic kinematics are reproducible with SHBR in young children, and these responses were lower than those elicited by slow treadmill walking.     

Sex and acute weighted vest differences in force production and joint work during countermovement vertical jumping

It is unclear whether weighted vest (WV) use improves countermovement vertical jump (CMVJ) performance by enhancing stretch-shortening cycle (SSC) function via increased storage and utilisation of elastic strain energy. In is also unknown whether WV use stimulates different responses in men and women. WV effects on energy storage and utilisation during CMVJ were examined in men and women. Nine men (25 ± 3 y; 89.7 ± 18.7 kg; 1.8 ± 0.1 m) and 12 women (24 ± 3 y; 62.7 ± 10.3 kg; 1.6 ± 0.1 m) performed CMVJ wearing a WV with (loaded) and without (unloaded) 10% added mass while kinematic and ground reaction force (GRF) data were obtained. A longer eccentric sub-phase and increased storage of elastic strain energy occurred when loaded. Increased positive joint work occurred during the concentric portion of loaded CMVJ. Women exhibited less positive hip work and greater positive ankle work than men during the unloading and eccentric sub-phases, respectively. Joint work was similar between sexes during the concentric sub-phase, likely due to decreased trunk extension excursion in men when loaded. Women and men employ different SSC strategies during the CMVJ, though the different strategies do not alter energy storage or concentric mechanical output.     

Test-retest reliability of jump execution variables using mechanography: a comparison of jump protocols

Mechanography during the vertical jump may enhance screening and determining mechanistic causes underlying physical performance changes. Utility of jump mechanography for evaluation is limited by scant test-retest reliability data on force-time variables. This study examined the test-retest reliability of eight jump execution variables assessed from mechanography. Thirty-two women (mean±SD: age 20.8 ± 1.3 yr) and 16 men (age 22.1 ± 1.9 yr) attended a familiarization session and two testing sessions, all one week apart. Participants performed two variations of the squat jump with squat depth self-selected and controlled using a goniometer to 80º knee flexion. Test-retest reliability was quantified as the systematic error (using effect size between jumps), random error (using coefficients of variation), and test-retest correlations (using intra-class correlation coefficients). Overall, jump execution variables demonstrated acceptable reliability, evidenced by small systematic errors (mean±95%CI: 0.2 ± 0.07), moderate random errors (mean±95%CI: 17.8 ± 3.7%), and very strong test-retest correlations (range: 0.73–0.97). Differences in random errors between controlled and self-selected protocols were negligible (mean±95%CI: 1.3 ± 2.3%). Jump execution variables demonstrated acceptable reliability, with no meaningful differences between the controlled and self-selected jump protocols. To simplify testing, a self-selected jump protocol can be used to assess force-time variables with negligible impact on measurement error.     

远固定力量训练在三级跳远运动员专项训练中的运用研究

运用数理统计法、实验法对三级跳远运动员进行远固定力量训练.结果显示运动员小肌肉群力量增强、肌肉募集时间缩短,加速了无负荷向超大负荷的转换速度,各跳的转换时间缩短,有助于增强运动员的专项素质,提高运动员三级跳远成绩和技术水平.     

下肢肌在踏跳动作中的储能

下肢肌肉储能大小和再利用率反映了运动员下肢肌的力量素质和动作技术的优劣 ,也是评定运动员下肢肌肉力量素质的动力学指标。我们采用高速摄影和三维测力 ,对 6名运动员在跳跃踏跳中 ,下肢肌肉的储能大小、负功利用率及其影响因素进行了研究。试验结果表明 :1 .外负荷变化时 ,踏跳缓冲结束瞬时肌肉的力值不同 ,且存在极值 ,此极值的大小与运动员的力量素质有关。 2 .下肢肌肉的储能与缓冲结束瞬时的力值之间有一定的比例关系 ,当肌肉受到一个最佳的拉伸力时 ,肌肉储能最多。 3.肌肉在向心收缩过程 ,对其在离心收缩过程中肌肉所做的负功的利用率 ,随着外负荷的增大而降低     

The relationship between mechanical stiffness and athletic performance markers in sub-elite footballers

This study investigated the relationship between several measures of lower-body stiffness and physical performance variables in 22 sub-elite male football players (mean ± SD; 21.9 ± 1.5 yr; 1.79 ± 0.06 m; 72.2 ± 7.2 kg). The participants were assessed for individual muscle stiffness of the Rectus Femoris (RF), Biceps Femoris (BF) and Medial Gastrocnemius (MG) muscles and vertical stiffness (Kvert) was also assessed assessed running acceleration, maximal sprint speed, agility, vertical jumping and muscular strength. Pearson’s correlations quantified the relationships and participants were also separated into relatively stiff (SG) and compliant groups (CG) for each variable. When ranked by Kvert the SG exhibited superior performance during sprinting, agility, jumping and strength (p ≤ 0.05) and when ranked by RF stiffness, SG exhibited superior sprint, agility and drop jump performance (p ≤ 0.05), while MG and BF stiffness were not related to performance. Higher stiffness appears to be beneficial to athletic performance for football players and therefore it may be beneficial for practitioners working with athletes that are required to perform dynamic activities to consider the contribution of stiffness to athletic performance.     

不同膝角静态蹲跳的生物力学研究

运用三维测力系统,对不同膝角静态蹲跳的测试结果进行比较分析：着重讨论了最大力值、蹬伸时间、冲量值等主要生物力学指标的变化规律及其对纵跳高度的影响。     

男子跳远运动员膝关节肌等速向心收缩的肌力研究

利用cybex-770等速测试与康复系统,对17名一级男子跳远运动员起跳腿的膝关节进行了等速向心收缩测试。所测试的指标包括相对峰力矩、相对总功、相对平均功率、峰力矩屈伸比等,对这些指标进行综合分析,并且结合跳远运动项目下肢肌最大力量和爆发力的项目特点,为优秀运动员有针对性的力量训练提供参考依据。     

发展跳远爆发力的生理学基础及其训练方法

肌肉绝对力量、运动速度,运动中枢同步调节,Ⅱ型肌纤维发展,磷酸原系统供能能力是决定跳远运动员爆发力的生理基础。长期系统合理的训练,将在中枢神经系统和肌肉运动速度的协调中产生专门性适应变化,提高速度性力量。根据17年来跳远教学与训练的实践体会,提出杠铃力量练习、跳跃练习(速度跳跃练习和远度跳跃练习),跳深练习、踝关节力量练习、．关键肌群力量练习等是发展跳远爆发力的有效训练方法。     

Power training in elite young soccer players: Effects of using loads above or below the optimum power zone

ABSTRACT

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.     

Redistributing load using wearable resistance during power clean training improves athletic performance

A popular method to improve athletic performance and lower body power is to train with wearable resistance (WR), for example, weighted vests. However, it is currently unknown what training effect this loading method has on full-body explosive movements such as the power clean. The purpose of this study was to determine what effects WR equivalent to 12% body mass (BM) had on the power clean and countermovement jump (CMJ) performance. Sixteen male subjects (age: 23.2?±?2.7 years; BM: 90.5?±?10.3?kg) were randomly assigned to five weeks of traditional (TR) power clean training or training with 12% BM redistributed from the bar to the body using WR. Variables of interest included pre and post CMJ height, power clean one repetition maximum (1RM), peak ground reaction force, power output (PO), and several bar path kinematic variables across loads at 50%, 70%, and 90% of 1RM. The main findings were that WR training: (1) increased CMJ height (8.7%; ES?=?0.53) and 1RM power clean (4.2%; ES?=?0.2) as compared to the TR group (CMJ height?=??1.4%; 1RM power clean?=?1.8%); (2) increased PO across all 1RM loads (ES?=?0.33–0.62); (3) increased barbell velocity at 90% 1RM (3.5%; ES?=?0.74) as compared to the TR group (?4.3%); and (4) several bar path kinematic variables improved at 70% and 90% 1RM loads. WR power clean training with 12% BM can positively influence power clean ability and CMJ performance, as well as improve technique factors.     

The effect of load and sex on kinematic and kinetic variables during the mid-thigh clean pull

Power is a fundamental component for many sporting activities; while the load that elicits peak power during different exercises and differences between sexes remains unclear. This study aims to determine the effect of sex and load on kinematic and kinetic variables during the mid-thigh clean pull. Men (n = 10) and women (n = 10) performed the mid-thigh clean pull at intensities of 40%, 60%, 80%, 100%, 120%, and 140% of one repetition maximum (1RM) power clean in a randomised and counter-balanced order, while assessing bar velocity, bar displacement, power, force, and impulse. Two-way analysis of variance revealed that men demonstrated significantly greater (p < 0.05) values for all variables across loads, excluding bar velocity. Men demonstrated significantly greater (p < 0.05) bar velocities with 40–80% 1RM; in contrast, women demonstrated significantly (p < 0.05) higher velocities with 120–140% 1RM. Irrespective of sex significantly greater (p < 0.05), system peak power, bar velocity, and displacement occurred with 40% 1RM. In contrast, peak force and impulse were significantly (p < 0.05) greater with 140% 1RM. When performing the mid-thigh clean pull, to maximise system power or bar velocity, lower loads (40–60% 1RM) are recommended. When training force production or impulse, higher loads (120–140% 1RM) are recommended, when using the mid-thigh clean pull.     

高水平跳远运动员起跳过程中摆动腿作用的研究

本文研究证明，跳远起跳过程中缓冲阶段拉动腿的摆动效果对上板速度、腾起初速度和跳远成绩有显著影响，起跳蹬伸阶段摆动腿的摆动制动加速度与腾起初速度和跳远成绩有高度的相关关系。     

中国优秀女子跳远运动员起跳过程摆动腿技术的运动学研究

运用高速摄影和影片解析法,对我国优秀女子跳远运动员起跳过程摆动腿技术进行研究发现,起跳过程中摆动腿紧密衔接的快速后蹬、加速前摆和制动前摆动作能促使身体重心在不更多损耗水平速度的基础上获得更大的垂直速度,并最终提高腾起瞬间身体重心的垂直位置、初速度和腾起角,对跳远起跳效果和成绩的提高具有显著的促进作用。     

对三级跳远运动中第二跳起跳腿缓冲与蹬伸技术重要性的运动学分析

采用高速摄影与影片解析、数理统计等研究方法,对参加全国田径冠军赛暨大奖总决赛女子三级跳远决赛的6名优秀运动员第二跳起跳腿缓冲与蹬伸技术指标进行运动学分析,并与国外优秀三级跳远运动员的相关参数比较研究,旨在诊断我国女子三级跳远运动员的技术现状及存在问题,指导和改进我国女子三级跳远的技术训练,为加强教学、训练的科学化程度提供参考与依据.