首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 750 毫秒
1.
The long jump has been widely studied in recent years. Two models exist in the literature which define the relationship between selected variables that affect performance. Both models suggest that the critical phase of the long jump event is the touch-down to take-off phase, as it is in this phase that the necessary vertical velocity is generated. Many three dimensional studies of the long jump exist, but the only studies to have reported detailed data on this phase were two-dimensional in nature. In these, the poor relationships obtained between key variables and performance led to the suggestion that there may be some relevant information in data in the third dimension. The aims of this study were to conduct a three-dimensional analysis of the touch-down to take-off phase in the long jump and to explore the interrelationships between key variables. Fourteen male long jumpers were filmed using three-dimensional methods during the finals of the 1994 (n = 8) and 1995 (n = 6) UK National Championships. Various key variables for the long jump were used in a series of correlational and multiple regression analyses. The relationships between key variables when correlated directly one-to-one were generally poor. However, when analysed using a multiple regression approach, a series of variables was identified which supported the general principles outlined in the two models. These variables could be interpreted in terms of speed, technique and strength. We concluded that in the long jump, variables that are important to performance are interdependent and can only be identified by using appropriate statistical techniques. This has implications for a better understanding of the long jump event and it is likely that this finding can be generalized to other technical sports skills.  相似文献   

2.
In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (-1.6% of body height compared with -1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (-0.4 m x s(-1)). Both this and their restricted approach speed (8.9 m x s(-1) at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (-2.3% of body height compared with -1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (-0.6 m x s(-1)). This, combined with their slower approach velocity (7.1 m x s(-1) at touch-down), restricted their performance.  相似文献   

3.
Abstract

In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (?1.6% of body height compared with ?1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (?0.4 m · s?1). Both this and their restricted approach speed (8.9 m · s?1 at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (?2.3% of body height compared with ?1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (?0.6 m · s?1). This, combined with their slower approach velocity (7.1 m · s?1 at touch-down), restricted their performance.  相似文献   

4.
The aim of this study was to establish the functions of the support leg in the long jump take-off with a three-element mechanical model spring, damper, and actuator The take-off motions of eleven male long jumpers, with personal bests from 6.45 to 7.99 m, were videotaped at 250 Hz and ground reaction forces were simultaneously recorded at 1 kHz. A two-dimensional 14-segment linked model was used to collect basic kinematic parameters. The spring, damper and actuator forces were determined from the displacement and velocity of the centre of mass and from ground reaction forces. Large spring and damper forces were exerted, and absorbed the impact force immediately after the touch-down. The spring force was also exerted from 25 to 75% of the take-off phase. The actuator force was dominant in the latter two-thirds of the take-off phase. Statistically significant correlations were found between the spring force impulse and the knee flexion during the take-off phase (r = 0.699, p < 0.05), and between the knee flexion and the angular velocity of the thigh at the touch-down (r = 0.726, p < 0.05). These results indicated that the jumper should retain less flexion of the take-off leg knee to increase the spring force, after a fast extension of the hip, and use a more extended knee at the touch-down to prevent excessive knee flexion.  相似文献   

5.
The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EGWBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg?1; P = 0.001), take-off velocity (0.1 cm · s?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EGWBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EGWBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.  相似文献   

6.
The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and measured jump distance, except for the knee joint angle at maximum shoulder extension angle, ankle joint angle at maximum shoulder extension angle, and shoulder joint angle at maximum knee flexion angle. Stepwise multiple regression analysis showed that sex, age, and body mass index accounted for 51.1% of the jump distance variance. Among all the kinematic variables, take-off distance and take-off speed were accounted for the most of the variation in the jump distance. Physical education teachers and coaches should consider special attention to these anthropometrics and kinematic aspects in improving the standing long jump performance in children.  相似文献   

7.
The purpose of the study was to investigate possible changes at step pattern and technical performance of the long jump approach run in seven young long jumpers by modifying the performance environment (long jump runway versus track lane) and the nested actions (run-through with take-off versus complete long jump). Our findings suggest that the step pattern and technical aspects of the approach run are affected by environmental context and nested task constraints. In terms of environmental context, it appears that practising the training routine of run-through followed by take-off on the long jump runway allows athletes to simulate competition conditions in terms of step regulation and technical efficacy. The task of run-through followed by take-off on the track lane failed to initiate visual perception, step regulation and technical efficiency at the steps preceding the instant of take-off. In terms of nested task constraints, when run-ups were followed by jump for distance instead of only a take-off, a higher level of consistency was achieved and step regulation was based on perception–action coupling. Practising long jump run-up accuracy at a setting not containing the informational elements of the performance environment fails to develop the key elements of the skill.  相似文献   

8.
Abstract

The aim of this study was to determine the influence of run-up speed on take-off technique in the long jump. Seventy-one jumps by an elite male long jumper were recorded in the sagittal plane by a high-speed video camera. A wide range of run-up speeds was obtained using direct intervention to set the length of the athlete's run-up. As the athlete's run-up speed increased, the jump distance and take-off speed increased, the leg angle at touchdown remained almost unchanged, and the take-off angle and take-off duration steadily decreased. The predictions of two previously published mathematical models of the long jump take-off are in reasonable agreement with the experimental data.  相似文献   

9.
To ensure precise foot placement on the take-off board, long jumpers visually regulate their stride pattern during their run-up. A relationship between how much visual guidance they use and the horizontal distance they jump has not, however, been quantified. Run-up precision is often practiced using run-throughs, which exclude the take-off and, therefore, the high physical stress of the complete long jump. The validity with which this common training method simulates the long jump approach remains, however, to be verified. Four state-standard long jumpers and two heptathletes completed two sessions, each comprising six runthroughs and six competition long jumps. A 50 Hz video camera was manually panned from an elevated platform to film each trial, to enable subsequent gait characteristic evaluations. Linear regression analyses identified that a longer visual regulation phase, measured in time, distance or number of strides, was a key predictor of long jump distance. The number of strides that were visually regulated during the long jump approach was, accordingly, positively correlated with long jump distance (r = 0.67, p = 0.001). The amount of visual regulation used during run-throughs was, however, less than half (p = 0.001) of that observed during long jump approaches. Our results should compel long jump coaches to supplement run-through training with additional visual guidance exercises, to encourage their athletes to visually regulate more of their long jump approach.  相似文献   

10.
对不同水平运动员进行跳高、跳远和三级跳远的技术指标和生理指标的测定。结果显示:相同项目运动时跳高组和跳远组的能量代谢显著大于一般组(P<0.05),这一差异与踏跳的瞬间用力有关,后者对腾空时间和运动成绩有一定的影响。从心率、氧债和MET值来看跳跃运动是属于中高强度以无氧代谢为主的运动项目。  相似文献   

11.
跳远起跳技术的运用在学界一直存有争议,为探讨跳远起跳技术的生物力学原理,选取跳远起跳动作作为研究对象,建立起跳动作的数学模型并在计算机上实施基于肌肉动力学层面的运动模拟。模拟结果表明:在增大人体重心垂直速度和重心的腾起角方面,膝关节肌较之髋关节肌都有更为显著的作用;在相同的着地距离下,增大小腿环节角与增大大腿环节角相比明显有利。  相似文献   

12.
对提高我国跳远成绩有效途径的探讨   总被引:35,自引:0,他引:35  
通过对我国跳远技术与世界先进技术的对比分析,对提高我国跳远成绩的有效途径进行了探讨,认为提高绝对速度能力是提高跳远成绩的最重要的途径;提高运动员快速起跳能力是关键;我国运动员技术上存在起跳腿的着地角较小、起跳扇角大的现象,影响了跑跳结合的连贯性,对获得腾起垂直速度不利;此外,还存在摆动腿的摆动时机晚、摆动速度慢、摆动幅度小等因素,这些都是影响我国跳远成绩提高的重要原因。  相似文献   

13.
The aim of this study was to determine the influence of run-up speed on take-off technique in the long jump. Seventy-one jumps by an elite male long jumper were recorded in the sagittal plane by a high-speed video camera. A wide range of run-up speeds was obtained using direct intervention to set the length of the athlete's run-up. As the athlete's run-up speed increased, the jump distance and take-off speed increased, the leg angle at touchdown remained almost unchanged, and the take-off angle and take-off duration steadily decreased. The predictions of two previously published mathematical models of the long jump take-off are in reasonable agreement with the experimental data.  相似文献   

14.
中外优秀男子跳远选手起跳阶段技术对比   总被引:7,自引:0,他引:7  
运用文献资料和比较分析的研究方法,对中外优秀男子跳远选手起跳阶段的技术进行研究。结果表明,我国选手的技术差距并非是水平速度损失率大,相反速度的利用率明显优于外国优秀选手;而起跳角度偏小。起跳腾起垂直速度慢等问题,是影响我国优秀男子跳远选手提高成绩的关键。  相似文献   

15.
跳远时摆动腿无积极的快速摆动与制动动作与起跳后身体明显前旋运动趋势都会影响跳远成绩,所以,有必要对跳远起跳时的前旋特点和起跳能力与腾空技术进行探讨,以期对跳远教练的教学有所帮助,提高运动员的跳远成绩。  相似文献   

16.
研究目的:跳远起跳过程中髋关节技术特征是跳远动作中最为重要的部分,对提高与改进跳远起跳技术有着重要的影响,掌握在跳远的起跳、着板、缓冲、蹬伸阶段"送髋"的角度和方法,为提高我国跳远水平提供具体量化参考指标。研究方法:根据我国运动员调控髋关节运动的状况和国内与国外优秀运动员跳高的差距,通过对比研究起跳过程中髋关节技术特征。研究结果和结论:跳远运动必须合理地完善起跳技术动作,在训练中专门发展髋关节肌肉的力量,以及髋关节灵活性,有意识地运用髋关节动作协调非常重要。  相似文献   

17.
So far, the relationship between wind and athletics performance has been studied mainly for 100 m sprint, based on simulation of biomechanical models, requiring several assumptions. In this study, this relationship is quantified empirically for all five horizontal jump and sprint events where wind is measured, with freely available competition results. After systematic scraping several elite and sub-elite results sites, the obtained results (n?=?150,169) were filtered and matched to athletes. A quadratic mixed effects model with athlete and season as random effects was applied to express the influence of wind velocity on performance in each event. Whether this effect differs with performance level was investigated by applying the model on subgroups based on performance level. In the fitted quadratic model, the linear coefficients were significant (p?p?p?=?.138). A 2.0?m?s?1 tail wind provides an average advantage of 0.125, 0.140 and 0.146?s for the 100, 200 and 100/110 m hurdles, respectively, and an advantage of 0.058 and 0.102 m for long jump and triple jump, respectively. Performance level had a significant effect on the wind influence only for 100 m (p??1 tail wind than elite athletes (~10?s). Practical formulas are presented for each event. These can easily be used correct results for wind speed, allowing better talent scouting and championship selection. This study demonstrates the efficacy of answering scientific questions empirically, through freely available data.  相似文献   

18.
利用世界优秀运动员的跳远技术参数和跳远踏跳阶段踏跳力一时间曲线,剖析助跑速度损失量、起跳快速支撑和蹬伸在跳远起跳垂直速度的生成机制中的运动学和动力学原因,对跳远垂直速度生成提出了新的见解,并为创新跳远训练提供了一条新的思路。  相似文献   

19.
A plausible explanation for the ancient long jump records from Greek antiquity is sought on the basis of pictorial and written sources, and corroborated with practical tests. Ancient sources report that athletes jumped more than 15?m with weights in their hands, which enabled them to jump further than without these weights. It is proposed that the ancient Greek long jump was a continuous succession of five standing broad jumps, in which the landing phase of one jump was also the countermovement for the next jump. Four trained athletes jumped further with (14.64?±?0.76?m, range 13.64?–?15.63?m) than without weights (13.88?±?0.70?m, range 12.60?–?14.75?m; P = 0.001). These results show that this technique is executable, fits with ancient written and pictorial sources, and allows trained modern athletes to jump distances well over 15?m. The extra distance jumped when using weights may be due to changes in the position of the jumper's centre of mass at take-off and at landing, and an increase in take-off velocity stemming from several biomechanical mechanisms.  相似文献   

20.
运用文献资料法、特尔菲法、运动生物力学测量法和数理统计法,对男子跳远运动员起跳力量训练方法进行定量研究。结果表明:8步助跑跳远、4步助跑5级单足跳、4步助跑5级跨步跳、起跳腿跳深摸高、起跳腿跳深跳远等5项练习被公认为发展跳远起跳力量的方法;8步助跑跳远、4步助跑单足跳、4步助跑5级跨步跳是与跳远专项非常接近的专项力量训练方法;跳深跳远练习可以促进运动员提高积极着板起跳技术。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号