原地连续纵跳动力学信息变化的特征

运用录像拍摄和三维测力同步测试的方法研究原地连续纵跳动力学信息变化特征.结果显示,缓冲结束瞬时力值、蹬伸力峰值、蹬伸平均功率和冲量都随着原地连续纵跳运动时间的延长而逐渐减小(P<0.05);不同频率原地连续纵跳缓冲结束瞬时力值和蹬伸力峰值对起跳效果的影响程度是不同的,60次/min频率作用下缓冲结束瞬时力值和蹬伸力峰值明显大于40次/min和50次/min两种频率(P<0.05),而起跳效果却较40次/min和50次/min两种频率差(P<0.05);3种频率原地连续纵跳过程中运动前期的恢复系数都大于1.     

沙滩原地纵跳与硬地原地纵跳动力学机制的比较研究

运用三维测力台，对我国12名沙滩女子排球运动员进行了沙滩和硬地2种介质上原地起跳的动力学测试。结果表明，沙滩原地纵跳和硬地原地纵跳的起跳用力方式相同，但动力学机制存在显著性差异，这是沙滩训练弹跳力的重要动力学依据。     

膝关节损伤对排球运动员急停纵跳的影响

目的:对辽宁省排球队女运动员下肢急停纵跳落地时的力矩和最大关节角度进行研究,以期对有膝关节损伤的排球运动员进行科学训练提供参考。方法:以14名辽宁省排球队女运动员为研究对象,将运动员分为两组,其中无伤组8人,损伤组6人,采用三维测力平台和红外光电运动捕捉系统,记录受试者在完成急停纵跳动作落地时的髋关节、膝关节、踝关节的力矩以及最大关节角度数据。结果:在急停纵跳落地时,损伤膝关节的旋转、收展力矩大于无伤组,屈伸力矩小于无伤组,损伤组的髋关节的屈伸、收展、旋转力矩均大于无伤组;损伤组的踝关节旋转力矩小于无伤组,收展力矩和屈伸力矩大于无伤组。损伤组的踝关节在屈伸、收展和旋转时的最大关节角度大于无伤组;损伤组的膝关节在屈伸和收展时的最大关节角度大于无伤组,旋转时小于无伤组;损伤的髋关节屈伸和收展时的最大关节角度大于无伤组,髋关节旋转时的最大关节角度左侧小于无伤组,右侧大于无伤组。结论:膝关节损伤的运动员完成急停纵跳动作落地时,通过代偿性改变增大髋关节力矩、增加膝关节旋转和收展力矩,增大踝关节收展和屈伸力矩,增加膝关节和髋关节在屈伸和收展时活动角度,增加膝关节屈伸和收展时活动角度来完成动作。     

原地连续纵跳的运动生物力学特征研究

为研究原地连续纵跳的运动生物力学特征,运用录像拍摄与三维测力同步测试的方法对其研究发现,不同频率作用下的时间参数存在一定差异,随着纵跳频率的增加,时间参数都表现出逐渐减小的趋贽.同一频率作用下随着运动时间的延长,支撑时间逐渐增人.蹬伸力峰值随着连续纵跳运动时间的延长呈现明显逐渐减小的趋势,不同频率原地连续纵跳蹬伸力峰值对起跳效果的影响程度是不同的;缓冲冲量和蹬伸冲量随运动时间的延长,也都呈现出明显的逐渐减小的趋势,并且运动前期的恢复系数人于1.     

摆臂在纵跳动作中的生物力学研究

本文主要运用三维测力系统,进行不同膝角的摆臂与不摆臂原地级跳测试与分析,探讨了摆臂在级跳动作中的作用及其生物力学特征和规律,丰富了已有研究内容。     

不同弹跳能力的3名运动员其原地纵跳的运动生物力学指标的比较

根据力学原理,本文建立了不同运动员间进行原地纵跳运动生物力学指标同步比较的方法。三名不同弹跳能力的运动员其原地纵跳进行了测力与录相同步分析。研究表明,能力强者在技术上表现出髋、膝、踝关节处极强的协调发力能力,而能力差者均出现滞后或超前的不协调性发力;不同能力的运动员在膝关节处发力较为接近,肩关节均是提前发力。但能力强者具有较强的肩关节发力能力,能力最差者则在肩、踝等关节处发力能力明显不足。     

负荷时间长短对纵跳能力影响的动力学研究

分析受试者在功率自行车上不同运动负荷时间后纵跳的动力学特征变化规律 ,研究结论 :①大强度持续运动约 3min左右 ,纵跳的爆发力、平均功率、平均力值等动力学指标显著上升 ;运动 5min后 ,上述指标的变化情况正好相反 ;②只有在适宜的运动负荷时间后 ,纵跳的动力学特征才进入有利于运动能力发挥的较好的组合状态     

1次力竭性运动前后纵跳某些动力学特征的研究

对12名男性受试者1次力竭性功率自行车运动前后纵跳的某些动力学特征测定,发现力竭性运动后纵跳的垂直方向的分力、冲量值下降(P<0.05);而水平方向的分力、冲量值增加(P<0.05)。     

不同快慢节奏对连续性原地纵跳影响的实验研究

采用录像和测力同步测试的方法，对10名受试者以80、120、160次，min3种不同节奏的连续性原地纵跳动作进行实验测试，结果表明：随着节奏的加快．支撑时间显著缩短；人体腾空的高度、质心下降与上升的最大速度等有显著性的下降；踝、膝、髋3个关节的屈曲程度，膝关节的伸屈角速度都有显著地下降；人体的刚度系数变大，弹性变小。     

增强式训练对青少年男子排球运动员垂直纵跳的影响研究

本文运用文献资料法、专家访谈法设计青少年排球运动员的增强式训练计划,采用实验法实施本训练方案,并通过数据分析探讨增强式训练对青少年男子排球运动员垂直纵跳的影响.研究结果表明,增强式训练对排球运动员垂直纵跳提升的效果较传统力量训练更加明显,为青少年排球运动员垂直纵跳训练计划的安排与实施提供一些参考.     

中外优秀男子跳远运动员助跑及起跳技术特征的比较

从绝对速度、助跑速度利用率、起跳支撑缓冲能力、起跳蹬伸时机等主要技术环节，对我国跳远运动员与世界跳远运动员进行了比较分析，找出差距所在，为我国跳远训练提供理论依据。     

Acute kinematic and kinetic adaptations to wearable resistance during vertical jumping

One variation of vertical jump (VJ) training is resisted or weighted jump training, where wearable resistance (WR) enables jumping to be overloaded in a movement specific manner. A two-way analysis of variance with Bonferroni post hoc contrasts was used to determine the acute changes in VJ performance with differing load magnitudes and load placements. Kinematic and kinetic data were quantified using a force plate and contact mat. Twenty sport active subjects (age: 27.8?±?3.8 years; body mass (BM): 70.2?±?12.2?kg; height: 1.74?±?0.78?m) volunteered to participate in the study. Subjects performed the counter movement jump (CMJ), drop jump (DJ) and pogo jump (PJ) wearing no resistance, 3% or 6% BM affixed to the upper or lower body. The main finding in terms of the landing phase was that the effect of WR was non-significant (P?>?.05) on peak ground reaction force. With regard to the propulsive phase the main findings were that for both the CMJ and DJ, WR resulted in a significant (P?<?.05) decrease in jump height (CMJ: ?12% to ?17%, DJ: ?10% to ?14%); relative peak power (CMJ: ?8% to ?17%, DJ: ?7% to ?10%); and peak velocity (CMJ: ?4% to ?7%, DJ: ?3% to ?8%); while PJ reactive strength index was significantly reduced (?15% to ?21%) with all WR conditions. Consideration should be given to the inclusion of WR in sports where VJ’s are important components as it may provide a novel movement specific training stimulus.

Highlights

• WR of 3 or 6 % BM provided a means to overload the subjects in this study resulting in decreased propulsive power and velocity that lead to a reduced jump height and landing force.

• Specific strength exercises that closely mimic sporting performance are more likely to optimise transference, therefore WR with light loads of 3–6% body mass (BM)appear a suitable tool for movement specific overload training and maximising transference to sporting performance.

• Practitioners can safely load their athletes with upper or lower body WR of 3–6% BM without fear of overloading the athletesover and above the landing forces they are typically accustomed too.

• As a training stimulus it would seem the WR loading provides adequate overload and athletes should focus on velocity of movement to improve power output and jump height i.e. take-off velocity.

     

Temporal and kinetic analysis of unilateral jumping in the vertical,horizontal, and lateral directions

Abstract

The aims of this study were to: (1) assess the reliability of various kinetic and temporal variables for unilateral vertical, horizontal, and lateral countermovement jumps; (2) determine whether there are differences in vertical ground reaction force production between the three types of jumps; (3) quantify the magnitude of asymmetry between limbs for variables that were established as reliable in a healthy population and whether asymmetries were consistent across jumps of different direction; and (4) establish the best kinetic predictor(s) of jump performance in the vertical, horizontal, and lateral planes of motion. Thirty team sport athletes performed three trials of the various countermovement jumps on both legs on two separate occasions. Eccentric and concentric peak force and concentric peak power were the only variables with acceptable reliability (coefficient of variation = 3.3–15.1%; intra-class correlation coefficient = 0.70–0.96). Eccentric and concentric peak vertical ground reaction force (14–16%) and concentric peak power (45–51%) were significantly (P < 0.01) greater in the vertical countermovement jump than in the horizontal countermovement jump and lateral countermovement jump, but no significant difference was found between the latter two jumps. No significant leg asymmetries (–2.1% to 9.3%) were found in any of the kinetic variables but significant differences were observed in jump height and distance. The best single predictors of vertical countermovement jump, horizontal countermovement jump, and lateral countermovement jump performance were concentric peak vertical power/body weight (79%), horizontal concentric peak power/body weight (42.6%), and eccentric peak vertical ground reaction force/body weight (14.9%) respectively. These findings are discussed in relation to monitoring and developing direction-specific jump performance.     

广东省大学生体质状况的纵向比较研究

通过对1991年、1995年、2000年3次广东省大学生体质健康状况的监测结果进行了分析研究，主要包括形态、机能、素质方面，并进行了城乡对比，以求掌握近10年来广东省大学生体质变化的规律。     

Mechanical parameters and flight phase characteristics in aquatic plyometric jumping

Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water. Kinetic force platform data from 12 young, male adults were collected for counter-movement jumps performed on land and in water at two different immersion depths. The specificity of jumps between environmental conditions was assessed using kinetic measures, temporal characteristics, and an assessment of the statistical relationship between take-off velocity and time in the air. Greater peak mechanical power was observed for jumps performed in the water, and was influenced by immersion depth. Additionally, the data suggest that, in the water, the statistical relationship between take-off velocity and time in air is quadratic. Results highlight the potential application of aquatic plyometric training as a cross-training tool for improving mechanical power and suggest that water immersion depth and fluid drag play key roles in the specificity of the take-off phase for jumping movements performed in the water.     

A review of models of vertical, leg, and knee stiffness in adults for running, jumping or hopping tasks

Abstract The 'stiffness' concept originates from Hooke's law which states that the force required to deform an object is related to a spring constant and the distance that object is deformed. Research into stiffness in the human body is undergoing unprecedented popularity; possibly because stiffness has been associated with sporting performance and some lower limb injuries. However, some inconsistencies surrounding stiffness measurement exists bringing into question the integrity of some research related to stiffness. The aim of this study was to review literature which describes how vertical, leg and knee stiffness has been measured in adult populations while running, jumping or hopping. A search of the entire MEDLINE, PubMed and SPORTDiscus databases and an iterative reference check was performed. Sixty-seven articles were retrieved; 21 measured vertical stiffness, 51 measured leg stiffness, and 22 measured knee stiffness. Thus, some studies measured several 'types' of stiffness. Vertical stiffness was typically the quotient of ground reaction force and centre of mass displacement. For leg stiffness it was and change in leg length, and for the knee it was the quotient of knee joint moments and change in joint angle. Sample size issues and measurement techniques were identified as limitations to current research.     

中外优秀竞技健美操运动员跳跃类难度动作的比较

对第10~11届世界健美操锦标赛我国与世界各项前3名运动员成套动作中所选的跳跃类难度动作进行了分析,结果显示:我国优秀竞技健美操运动员在成套动作中选用的跳跃类难度动作的数量和分值上均高于世界前3名选手;我国优秀竞技健美操运动员选用的跳跃类难度动作类型主要偏重于屈体分腿跳类,动作的完成比世界优秀运动员选用的科萨克跳类的难度大;我国优秀竞技健美操运动员选用的跳跃类难度动作主要分布在整套操的前半套,而世界优秀运动员主要分布在整套操的后半套,这对运动员的专项体能及下肢动力性力量的要求较高,这说明我国优秀竞技健美操运动员与世界优秀运动员相比下肢动力有一定的差距。     

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.     

A review of models of vertical,leg, and knee stiffness in adults for running,jumping or hopping tasks

Abstract

The ‘stiffness’ concept originates from Hooke's law which states that the force required to deform an object is related to a spring constant and the distance that object is deformed. Research into stiffness in the human body is undergoing unprecedented popularity; possibly because stiffness has been associated with sporting performance and some lower limb injuries. However, some inconsistencies surrounding stiffness measurement exists bringing into question the integrity of some research related to stiffness. The aim of this study was to review literature which describes how vertical, leg and knee stiffness has been measured in adult populations while running, jumping or hopping. A search of the entire MEDLINE, PubMed and SPORTDiscus databases and an iterative reference check was performed. Sixty-seven articles were retrieved; 21 measured vertical stiffness, 51 measured leg stiffness, and 22 measured knee stiffness. Thus, some studies measured several ‘types’ of stiffness. Vertical stiffness was typically the quotient of ground reaction force and centre of mass displacement. For leg stiffness it was and change in leg length, and for the knee it was the quotient of knee joint moments and change in joint angle. Sample size issues and measurement techniques were identified as limitations to current research.