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1.
Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during ive-flight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver’s scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD’s of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.  相似文献   

2.
Abstract

A modelling approach was used in the present study to investigate the role of the hip muscles during the come-out of forward and inward multiple somersaulting dives in a pike position. A planar two-segment model was used to simulate the somersault and come-out of three commonly performed dives from a 3-m springboard: forward two-and-one-half somersault pike dive (105B), forward three-and-one-half somersault pike dive (107B), and inward two-and-one-half somersault pike dive (405B). Three simulations were run for each dive: (1) hip angle was constrained to be constant, (2) hip torque was removed after 0.1 s, and (3) hip angle was constrained to a typical come-out time history used by elite divers. Simulation results indicated that hip flexion torque was required both to maintain a rigid pike position during somersault (range = 205.5–282.3 Nm) and to control the hip extension movement during the come-out (peak torque range = 355.8–548.1 Nm) in forward and inward multiple somersaulting dives. Coaches and divers should be aware that dry-land exercise drills producing hip extension movement by concentric actions of the hip extensor muscles do not replicate the neuromuscular control during the come-out of fast rotating dives.  相似文献   

3.
The purpose of this study was to compare the inward two and one half somersault dive in a tuck position (405C) performed by females (n = 22) and the inward two and one half somersault dive in a pike position (405B) performed by males (n = 24) to determine changes required by females to successfully perform 405B. Key performance variables in inward dives were also compared to those of backward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitized to obtain times and postures of the divers at specific events including takeoff and entry. Estimates of flight height and mass-normalised work done on the springboard were obtained from flight times. Some females worked the springboard strongly enough to generate sufficient height and rotation to perform 405B. Males performed 405B comfortably because they achieved better height and rotation than the females. A comparison of backward and inward dives revealed that divers are able to attain greater height in backward dives than inward dives.  相似文献   

4.
The purpose of this study was to compare the reverse two and one half somersault dive in a tuck position (305C) performed by females (n = 24), and the reverse two and one half somersault dive in a pike position (305B) performed by males (n = 21), to determine changes required by females to successfully perform 305B. Key performance variables in reverse dives were also compared to those of forward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including hurdle landing, takeoff, and entry. Estimates of hurdle flight height and mass-normalised work done on the springboard were obtained from hurdle and flight times. The males did more work on the springboard to achieve greater height and rotation than females. Females performing 305C had less hip and knee flexion at hurdle landing than males performing 305B and took longer to achieve maximum hip flexion after takeoff from the springboard. To progress from 305C to 305B females need to adjust their techniques to put more energy into the system. Desirable changes include increased height in the hurdle and increased hip and knee flexion prior to hurdle landing. Comparison of results for reverse dives with data previously presented for forward dives indicated that divers are more limited in the number of somersaults and dive position in reverse dives than forward dives despite equivalent or better height in reverse dives than forward dives.  相似文献   

5.
Diving     
The purpose of this study was to compare the reverse two and one half somersault dive in a tuck position (305C) performed by females (n = 24), and the reverse two and one half somersault dive in a pike position (305B) performed by males (n = 21), to determine changes required by females to successfully perform 305B. Key performance variables in reverse dives were also compared to those of forward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including hurdle landing, takeoff, and entry. Estimates of hurdle flight height and mass‐normalised work done on the springboard were obtained from hurdle and flight times. The males did more work on the springboard to achieve greater height and rotation than females. Females performing 305C had less hip and knee flexion at hurdle landing than males performing 305B and took longer to achieve maximum hip flexion after takeoff from the springboard. To progress from 305C to 305B females need to adjust their techniques to put more energy into the system. Desirable changes include increased height in the hurdle and increased hip and knee flexion prior to hurdle landing. Comparison of results for reverse dives with data previously presented for forward dives indicated that divers are more limited in the number of somersaults and dive position in reverse dives than forward dives despite equivalent or better height in reverse dives than forward dives.  相似文献   

6.
Diving     
The purpose of this study was to compare the backward two and one half somersault dive in a tuck position (205C) performed by females (n = 22) and the backward two and one half somersault dive in a pike position (205B) performed by males (n = 27) and by females (n = 6) to determine changes required by females to successfully perform 205B. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including maximum depression, takeoff, and entry. Estimates of mass‐normalised work done on the springboard were obtained from flight times. Males performed 31% more mass‐normalised work on the springboard to gain height than females. Based on the dive scores and the short time to extend and prepare for entry it was concluded that females are not yet able to perform 205B with the same quality as they perform 205C. Females performing backward dives need to adjust their techniques to allow increased work on the springboard to generate height and rotation. Also, faster contraction of the hip flexors may allow them to achieve the tightest position more quickly to complete rotations with more time to prepare for entry.  相似文献   

7.
The purpose of this study was to compare the backward two and one half somersault dive in a tuck position (205C) performed by females (n = 22) and the backward two and one half somersault dive in a pike position (205B) performed by males (n = 27) and by females (n = 6) to determine changes required by females to successfully perform 205B. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitised to obtain times and postures of the divers at specific events including maximum depression, takeoff, and entry. Estimates of mass-normalised work done on the springboard were obtained from flight times. Males performed 31% more mass-normalised work on the springboard to gain height than females. Based on the dive scores and the short time to extend and prepare for entry it was concluded that females are not yet able to perform 205B with the same quality as they perform 205C. Females performing backward dives need to adjust their techniques to allow increased work on the springboard to generate height and rotation. Also, faster contraction of the hip flexors may allow them to achieve the tightest position more quickly to complete rotations with more time to prepare for entry.  相似文献   

8.
Kinetics and full body kinematics were measured in ten elite goalkeepers diving to save high and low balls at both sides of the goal, aiming to investigate their starting position, linear and angular momentum, and legs' contribution to end-performance. Our results showed that goalkeepers adopted a starting position with a stance width of 33 ± 1% of leg length, knee flexion angle of 62 ± 18° and hip flexion angle of 63 ± 18°. The contralateral leg contributed more than the ipsilateral leg to COM velocity (p < 0.01), both for the horizontal (2.7 ± 0.1 m·s?1 versus 1.2 ± 0.1 m·s?1) and for the vertical component (3.1 ± 0.3 m·s?1 versus 0.4 ± 0.2 m·s?1). Peak horizontal and peak angular momenta were significantly larger (p < 0.01) for low dives than for high dives with a mean difference of 55 kg·m·s?1 and 9 kg·m2·s?1, respectively. In addition, peak vertical momentum was significantly larger (p < 0.01) for high dives with a mean difference between dive heights of 113 kg·m·s?1. Coaches need to highlight horizontal lateral skills and exercises (e.g. sideward push-off, sideward jumps), with emphasis on pushing-off with the contralateral leg, when training and assessing goalkeeper’s physical performance.  相似文献   

9.
The optimum pre-flight characteristics of the Hecht and handspring somersault vaults were determined using a two-segment simulation model. The model consisted of an arm segment and a body segment connected by a frictionless pin joint, simulating the vault from the Reuther board take-off through to landing. During horse contact, shoulder torque was set to zero in the model. Five independent pre-flight variables were varied over realistic ranges and an objective function was maximized to find the optimum pre-flight for each vault. The Hecht vault required a low trajectory of the mass centre during pre-flight, with a low vertical velocity of the mass centre and a low angular velocity of the body at horse contact. In contrast, the optimum handspring somersault required a high pre-flight trajectory, with a high angular velocity of the body and a high vertical velocity at horse contact. Despite the simplicity of the model, the optimum pre-flights were similar to those used in competitive performances.  相似文献   

10.
Attempts to increase dive height by introducing a period of flight in the final approach step preceding the hurdle of dives from forward and reverse groups were investigated. One study involved 11 collegiate-level divers experienced in both traditional and hurdle preflight techniques. In a second study, dives executed by 9 national-level women were compared. Dives with a hurdle preflight had shorter final approach steps and greater hurdle flight durations. Flight time differences in favor of hurdle preflight techniques diminished from final approach step through hurdle flight to dive flight. Although the collegiate-level divers had longer dive flight times when using a hurdle preflight, it was suggested that the costs of these techniques may outweigh their potential benefits.  相似文献   

11.
We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.  相似文献   

12.
采用高速摄影和影片解析的方法，从运动学角度对赵卫华完成该动作各阶段技术进行分析。结果表明，主要矛盾是起跳阶段身体重心垂直速度偏低，空中阶段翻转角速度过慢则为次要矛盾。建议今后训练重点应围绕挖掘运动员潜力，提高腾空高度即最大限度地增大蹬离瞬时的垂直速度进行按排。  相似文献   

13.
A proficient serve is critical to successful tennis performance, and consequently coaches and players devote considerable time refining this stroke. In so doing, a wide variety of interventions are used or trialled, generally with very little empirical support. This study examined the efficacy of a commonly used service intervention, where players focus on exaggerating their finish (arabesque) position to promote specific changes in lower limb and trunk kinematics. The kinematics of eight high-performance junior players hitting flat serves were compared to the acute changes in kinematics elicited by the arabesque follow through position on serves using a 10-camera VICON MX motion analysis system. The significantly greater front (landing leg) hip flexion (p < 0.05) and forward trunk flexion (p < 0.05) confirmed the more exaggerated arabesque landing position following the arabesque instruction. The arabesque instruction resulted in increased frontal plane trunk range of motion and peak angular velocity in the forward swing, and increased leg drive during the drive phase. Practically, the results support the use of the arabesque instruction, effectively promoting the desired acute changes in trunk kinematics (i.e. increased frontal plane trunk rotation angular velocity) and leg drive (i.e. increased back knee extension angular velocity and front/back vertical hip velocity).  相似文献   

14.
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15.
Abstract

There is a risk of hip injury in dives to the side by soccer goalkeepers. In this study, we assessed hip loading in goalkeepers when performing such dives. The experiments were conducted in a laboratory setting using an in-ground force plate as well as on a grass surface when the athletes were equipped with force sensors. The forces acting on the hip were measured and high-speed video analysis was performed, allowing the investigation of the dive characteristics and techniques. The peak force values recorded in the laboratory setting ranged from 3 to 8 kN, which corresponded to 4.2–8.6 times body weight. The vertical impact velocities reached 3.25 m · s?1. In the field experiments, a hip loading of 87–183 N · cm?2 was determined. We found that goalkeepers who perform a rolling motion reduce their hip loading. The data provided by this study add to the biomechanics database and contribute to the establishment of injury criteria. Such information is necessary to develop and implement strategies to help prevent hip injuries.  相似文献   

16.
赵云娟  龚铭新  黄勇 《体育科研》2009,30(4):86-87,99
采用图像解析的方法对郭佳浩“倒手翻接屈体后空翻两周半”技术动作进行运动学分析研究,研究表明,郭佳浩助跑速度快;上板踏跳快速有力．垂直速度增加较高;撑马时间短促有力;第二腾空横轴和纵轴转体角速度快,空中姿态保持较好,落地较稳;第二腾空时间长,腾空高度高;不足之处在于他触马瞬间到离马瞬间过程中垂直速度有所减小。  相似文献   

17.
通过文献、观察比赛录像和统计等方法,对37、38和39届世界体操锦标赛及28届奥运会女子自由体操决赛前八名的技巧翻腾动作进行了比较研究。结果表明,2006年前的三届比赛,D组及以上难度单个翻腾动作总数没变,SE组数量有所增加,39届世锦赛D组及以上难度增加了近三分之一,E组及以上难度占了72.4%;空翻类型仍以向后为主,但比例趋向减少,向前类型比例的增加是前空翻二周数量增多所致;具有连接加分的技巧串类型不断增多,0.2加分技巧串比例提高。  相似文献   

18.
Gymnastics     
The 16 highest‐scored Roche vaults (G1) performed during the 2000 Olympic Games were compared with those receiving the 16 lowest‐scores (G2). A 16‐mm motion picture camera operating at 100 Hz recorded the vaults during the competition. The results of t tests (p < .05) indicated G1, compared to G2, had (a) shorter time of board support, greater normalised average upward vertical force and backward horizontal force exerted by the board, greater change in the vertical velocity while on the board, and greater vertical velocity at board take‐off, (b) comparable linear and angular motions in pre‐flight, (c) smaller backward horizontal impulse exerted by the horse, smaller loss of the horizontal velocity while on the horse, and greater horizontal and vertical velocities at horse take‐off, (d) greater height and larger horizontal distance of post‐flight, (e) higher body mass centre at knee release, and (f) higher mass centre, greater normalised moment of inertia, and smaller vertical velocity at mat touchdown. Therefore, gymnasts and coaches should focus on sprinting the approach; blocking and pushing‐off the take‐off board rapidly and vigorously; departing the board with a large vertical velocity; exerting large downward vertical force and small forward horizontal force from the handstand position while on the horse; departing the horse with large horizontal and vertical velocities; and completing the majority of the double salto forward near the peak of trajectory and releasing the knees above the top of the horse to prepare for a controlled landing.  相似文献   

19.
目的:研究踺子转体180°前手翻接直体前空翻类跳马动作,揭示这类跳马的运动学规律和技术特点.方法:对程菲和洪淑贞完成的"踺子转体180°前手翻接直体前空翻转体180"(简称"R180"),以及程菲完成的"踺子转体180°前手翻接直体前空翻转体540°"("程菲跳")进行三维运动学分析,对三组跳马动作身体重心的水平速度和垂直速度、主要关节的位移、关节角度、身体翻转角速度等运动学参数进行对比分析.结果:三组动作踏板时重心水平速度基本相同,踏板及推手阶段关键位置的关节角度相近,但"程菲跳"推离马重心垂直速度和第二腾空时间明显高于"R180",第二腾空转体角速度略大于"R180"的3倍,而翻腾角速度略小.结论:踺子转体180°前手翻接直体前空翻类跳马动作触马前的技术动作基本相同,难度较高的技术动作需要更高的推离马垂直速度和更快的第二腾空转体角速度.  相似文献   

20.
The purpose of the present study was to evaluate the concurrent validity and test-retest repeatability of torso-worn IMU-derived power and jump height in a counter-movement jump test. Twenty-seven healthy recreationally active males (age, 21.9 [SD 2.0] y, height, 1.76 [0.7] m, mass, 73.7 [10.3] kg) wore an IMU and completed three counter-movement jumps a week apart. A force platform and a 3D motion analysis system were used to concurrently measure the jumps and subsequently derive power and jump height (based on take-off velocity and flight time). The IMU significantly overestimated power (mean difference = 7.3 W/kg; P < 0.001) compared to force-platform-derived power but good correspondence between methods was observed (Intra-class correlation coefficient [ICC] = 0.69). IMU-derived power exhibited good reliability (ICC = 0.67). Velocity-derived jump heights exhibited poorer concurrent validity (ICC = 0.72 to 0.78) and repeatability (ICC = 0.68) than flight-time-derived jump heights, which exhibited excellent validity (ICC = 0.93 to 0.96) and reliability (ICC = 0.91). Since jump height and power are closely related, and flight-time-derived jump height exhibits excellent concurrent validity and reliability, flight-time-derived jump height could provide a more desirable measure compared to power when assessing athletic performance in a counter-movement jump with IMUs.  相似文献   

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