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1.
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
2.
对我国5.60m水平以上3名优秀男子撑竿跳高运动员的助跑起跳技术进行分析.研究认为,现阶段我国运动员的助跑速度同世界级运动员差距不大,但助跑节奏存在问题,倒三步重心速度变化不合理;倒一步步长受限于起跳点,刘飞亮和杨雁盛助跑阶段最后两步步长变化不合理;刘飞亮采用“自由起跳”的起跳方式,“自由起跳”属于“跳插同时”型,主要技术特征表现为握竿高度高,翻竿时机早,起跳距离远,插穴时间充分,撑竿表现为“反弓”弧度明显,在起跳离地瞬间“正弓”才开始出现;建议杨泉和杨雁盛增加起跳距离,改进翻竿时机,刘飞亮提高最后两步节奏的稳定性. 相似文献
3.
Muraki Y Ae M Yokozawa T Koyama H 《Sports biomechanics / International Society of Biomechanics in Sports》2005,4(1):1-15
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
4.
运用影片拍摄及解析的方法对成绩在 6.30 m以上的 6名中国优秀女子运动员摆动腿在助跑最后一步和起跳过程中的运动学特征进行分析。研究表明,在助跑最后一步蹬伸阶段优秀女跳远运动员摆动腿髋的水平速度与水平速度增加值呈高度正相关;着板时,摆动腿摆动角速度与起跳脚水平速度呈高度负相关;起跳过程的缓冲阶段中,摆动腿的摆动使身体重心高度呈上升趋势,同时垂直速度持续升高,占腾起垂直分速度值的53.1％。 相似文献
5.
Bradshaw EJ Aisbett B 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(1):1-14
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
6.
龙跃玉 《上海体育学院学报》2008,32(2):76-82
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
7.
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
8.
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
9.
运用文献资料法、信息技术等方法分析比较国际田联钻石联赛上海站男子跳远前三运动员助跑与起跳技术的运动学特征,为提高我国男子跳远水平提供训练方向。研究表明：门科夫后4步提速不明显,趋势变化较平缓,卢瑟福德助跑节奏稳定,仅在后1步时有加速踏板,不利于起跳发挥,李金哲助跑步幅较大、频率加快、提速明显,后3步节奏变化稳定,为高速助跑中完成起跳技术提供了保障。李金哲与门科夫、卢瑟福德相比,助跑结束阶段,摆动腿折叠不足,起跳蹬伸受限,垂直、水平速度利用率小,引起垂直高度受限,导致支撑缓冲时间增长。 相似文献
10.
文章运用文献资料、数理统计和图像解析的研究方法,对二级跳远运动员的运动学指标进行研究。结果表明：（1）二级运动员起跳时间平均值是0.130s,缓冲时间平均值为0.048s,蹬伸时间平均值0.082s。缓冲时间、蹬伸时间与整个起跳时间过长。这与二级运动员本身身体素质和技术动作的优劣存在很大关系;（2）二级运动员着板瞬间,摆动腿的摆动角速度平均值为451.72°/s,膝关节角度平均为87.14°上板速度为8.58m/s,与前人的研究有出入;（3）二级运动员速度利用率为76.30%,速度利用率明显低于优秀运动的速度利用率。腾起角平均为26.66°,明显高于优秀运动员的18°-25°;（4）在蹬伸阶段摆动角速度的最大值与腾起角和成绩明显正相关。 相似文献
11.
目的:通过分析我国优秀男子跳台滑雪运动员实地起跳阶段运动学、起跳运动模式等指标,探究影响我国男子跳台滑雪运动员飞行距离的主要起跳因素。方法:1)选择8名我国男子跳台滑雪运动员作为研究对象,在日本长野县白马村K90跳台训练基地采集3次起跳阶段二维运动学数据,采用广义估计模型(GEE)分析影响飞行距离的实地起跳阶段运动学因素。2)截取平昌冬奥会排名前10的男子跳台滑雪选手决赛起跳阶段视频数据,采用单因素方差分析研究国内外运动员起跳阶段特定时刻肢体角度差异。3)实验室内使用1台Z camera高速摄像机和1块Kistler 9281EA测力台采集运动员静蹲跳(squat jump,SJ)、反向跳(countermovement jump,CMJ)、模拟跳跃(imitation jump,IJ)、下落跳(drop jump,DJ)的动力学及运动学数据,采用Pearson相关分析检验实验室内运动学及动力学指标与飞行距离间的相关性。结果:1)在实地起跳阶段运动学方面,起跳起始时刻躯干与助滑道夹角、小腿与助滑道夹角、髋关节角、膝关节角,以及起跳阶段的髋关节峰值角速度、膝关节平均角速度、起跳结束时刻膝关节角及髋关节角为飞行距离的影响因素(P<0.05)。2)在起跳阶段运动模式及力量特点方面,IJ重心最低处膝外翻指数(r=0.731)、DJ膝外翻最小值(r=0.713)、CMJ起跳阶段地面反作用力峰值(r=0.710)、CMJ蹬伸冲量(r=0.752)、SJ(r=0.723)及CMJ起跳峰值功率(r=0.762)均与飞行距离呈正相关。3)对比国内外运动员起跳阶段特定时刻肢体角度发现,国外优秀运动员起跳起始时刻小腿与助滑道夹角(53.54°±3.14°)显著小于我国运动员(57.62°±4.62°),出台瞬间小腿与助滑道夹角(58.22°±2.13°)显著小于我国运动员(65.59°±3.84°),大腿与助滑道夹角(73.28°±6.15°)显著大于我国运动员(58.77°±3.16°),起跳阶段结束时刻髋关节角度(175.23°±1.96°)显著大于我国运动员(156.37°±13.13°)。结论:我国跳台滑雪运动员起跳阶段起跳起始时刻应尽量降低身体重心以减少阻力,并适当提高膝关节角来提高出台后肢体伸展程度。起跳过程中提高膝关节蹬伸力量,同时适当降低髋关节伸展速度,避免风阻对躯干造成不利影响。室内及实地训练过程中,应在提升蹬伸爆发力的同时避免膝关节过度外翻,提高蹬伸力量及传递效率。 相似文献
12.
A theoretical analysis of the long jump take-off is presented, with the conclusion that elastic effects are important. Measured data from the literature for groups of top athletes and average performers in the long jump confirm this conclusion and lead to an estimate of elastic energy conversion efficiency, which is very low (between 0.2 and 0.3), in contrast with much higher conversion efficiencies for the running stride. 相似文献
13.
Koyama H Muraki Y Ae M 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):139-153
We investigated the immediate effects of the combined use of inclined and raised flat boards on the take-off motion of the long jump. Eight male long jumpers were videotaped with two high-speed video cameras (250 Hz) set perpendicular to the runway. The athletes jumped with three modified take-off boards: upward-inclined boards of two different inclinations (2.5 and 5.0 degrees), and a raised flat board (50 mm high). The jumpers performed pre- and post-jumps using their own techniques before and after use of the boards to test their effects. The post- jump revealed significantly less reduction in the horizontal velocity during the take-off than the pre-jump, and the effectiveness of converting the velocity from horizontal to vertical increased significantly in the post-jump. The post-jump demonstrated significantly less knee flexion of the take-off leg during take-off. The reduced knee flexion and slower extension velocity of the take-off leg in the second phase of the post-jump contributed to increasing the knee extension torque in the second phase and resulted in the increases in vertical ground reaction force and vertical velocity. These results suggest that the combined use of the inclined and raised flat boards induced immediate effective changes in the kinematics and kinetics of the take-off motion and represent appropriate training tools for take-off techniques of the long jump. 相似文献
14.
第11届全运会女子三级跳远运动员三跳技术的运动学分析 总被引：3，自引：0，他引：3
对参加第11届全运会田径比赛女子三级跳远决赛前8名运动员三跳技术的相关运动学参数进行研究,结果表明:我国女子三级跳远运动员助跑绝对速度和起跳速度利用率较差,只有8.96 m/s和95.5%,与世界女子三级跳运动员的9.41 m/s和98.2%相比,差异具有显著性(P<0.01);起跳脚着地与离地瞬间身体重心水平速度较差,只有8.71 m/s,与世界选手的9.33 m/s相比,差异有非常显著性(P<0.01);单足跳与跨步跳时的身体重心腾起角度适宜,分别为(17.19±4.37)°、(15.07±4.12)°,但最后跳跃的身体重心腾起角过大(23.57±4.12)°,超过世界运动员的16°~20°;三跳的支撑总时间较长,起跳效果不理想。 相似文献
15.
Collins MH Pearsall DJ Zavorsky GS Bateni H Turcotte RA Montgomery DL 《Journal of sports sciences》2000,18(2):83-90
The aims of this study were to determine if there are significant kinematic changes in running pattern after intense interval workouts, whether duration of recovery affects running kinematics, and whether changes in running economy are related to changes in running kinematics. Seven highly trained male endurance runners (VO2max = 72.3+/-3.3 ml x kg(-1) x min(-1); mean +/- s) performed three interval running workouts of 10 x 400 m at a speed of 5.94+/-0.19 m x s(-1) (356+/-11.2 m x min(-1)) with a minimum of 4 days recovery between runs. Recovery of 60, 120 or 180 s between each 400 m repetition was assigned at random. Before and after each workout, running economy and several kinematic variables were measured at speeds of 3.33 and 4.47 m x s(-1) (200 and 268 m x min(-1)). Speed was found to have a significant effect on shank angle, knee velocity and stride length (P < 0.05). Correlations between changes pre- and post-test for VO2 (ml x kg(-1) x min(-1)) and several kinematic variables were not significant (P > 0.05) at both speeds. In general, duration of recovery was not found to adversely affect running economy or the kinematic variables assessed, possibly because of intra-individual adaptations to fatigue. 相似文献
16.
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
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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.
Dan K. Ramsey Ryan L. Crotin 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(5):553-570
Propulsion and bracing ground reaction force (GRF) in overhand throwing are integral in propagating joint reaction kinetics and ball velocity, yet how stride length effects drive (hind) and stride (lead) leg GRF profiles remain unknown. Using a randomised crossover design, 19 pitchers (15 collegiate and 4 high school) were assigned to throw 2 simulated 80-pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and radar gun tracked each throw. Vertical and anterior–posterior GRF was normalised then impulse was derived. Paired t-tests identified whether differences between conditions were significant. Late in single leg support, peak propulsion GRF was statistically greater for the drive leg with increased stride. Stride leg peak vertical GRF in braking occurred before acceleration with longer strides, but near ball release with shorter strides. Greater posterior shear GRF involving both legs demonstrated increased braking with longer strides. Conversely, decreased drive leg propulsion reduced both legs’ braking effects with shorter strides. Results suggest an interconnection between normalised stride length and GRF application in propulsion and bracing. This work has shown stride length to be an important kinematic factor affecting the magnitude and timing of external forces acting upon the body. 相似文献