Trade-offs between horizontal and vertical velocities during triple jumping and the effect on phase distances

Abstract

For the full text of this licence, please go to: http://creativecommons.org/licenses/by-nc-nd/2.5/ 1 Journal of Biomechanics, 46, 979-983, 2013 Trade-offs between horizontal and vertical velocities during triple jumping and the effect on phase distances S.J. Allen, M.A. King, and M.R. YeadonSchool of Sport, Exercise, and Health Sciences, Loughborough University, LE11 3TU, UK AbstractThe triple jump is an athletic event involving three ground contact phases during which athletes must trade off the maintenance of horizontal velocity against the generation of vertical velocity. Previous studies have indicated that individual athletes have a linear relationship between the loss in horizontal velocity and the gain in vertical velocity during each phase. This study used computer simulation to investigate the effects of constraining the takeoff velocities in the hop phase on the velocity trade-offs in this and subsequent phases. Kinematic data were obtained from an entire triple jump using a Vicon automatic motion capture system, and strength and anthropometric data were collected from the triple jumper. A planar 13-segment torque-driven subject-specific computer simulation model was used to maximise the distance of each phase by varying torque generator activation timings using a genetic algorithm. Vertical takeoff velocities in the hop phase were constrained to be 100%, ±10%, ±20%, and ±30% of the performance velocity, and subsequent phases were optimised with initial conditions calculated from the takeoff of the previous phase and with no constraints on takeoff velocity. The results showed that the loss in horizontal velocity during each contact phase was strongly related to the vertical takeoff velocity (R 2 = 0.83) in that phase rather than the overall gain in vertical velocity as found in previous studies. Maximum overall distances were achieved with step phases which were 30% of the total distance of the triple jump confirming the results of experimental studies on elite triple jumpers.

The effect of increasing strength and approach velocity on triple jump performance

“…An example is shown in Figure 5 where vertical forces, and therefore impulses, increased as strength increased, whereas horizontal forces were similar. It has been proposed that the ability of an athlete to 'convert' horizontal velocity to vertical velocity is subject-specific (Yu and Hay, 1996;Allen et al, 2013). The results of this study indicate that, rather than being entirely subject-specific, it may be dependent on both the strength and approach velocity of the athlete: stronger athletes can achieve more vertical velocity for a unit loss in horizontal velocity, and athletes of a given strength can achieve more vertical velocity for a unit loss in horizontal velocity with decreasing approach velocity.…”

“…The foot-ground interface was modelled using horizontal and vertical non-linear spring-dampers situated at the heel, ball, and toe of each foot (Allen et al, 2012). Viscoelastic parameters representing the wobbling masses and the foot-ground interface were previously determined via optimisation; these parameters were varied in order to minimise the differences between simulated ground reaction force and kinematic data, and equivalent performance data (Allen et al, 2013). The performance data was matched using a simulation of the complete triple jump (Allen et al, 2016) and this was subsequently used as the base simulation for optimisations.…”

“…Typically, proportionately more horizontal velocity is lost as gains in vertical velocity increase, due to the requisite increase in plant angle leading to more energy dissipation by the stance leg and larger changes in potential energy of the mass centre. It has been proposed that the ability of an athlete to 'convert' horizontal velocity to vertical velocity is subject-specific (Yu and Hay, 1996;Allen et al, 2013) but the effects of strength and approach velocity on this relationship have not been investigated. It is possible that an increase in strength would allow a more efficient conversion of horizontal velocity to vertical velocity because the leg would be better able to resist flexion, and hence energy dissipation due to eccentric muscle actions.…”

The Velocity Conversion Coefficient and Consistency for the Optimal Phase Ratio on the Performance of the Women's Triple Jump

“…속도 전환(gain & loss velocity), 그리고 속도 전환계수를 통 한 최적의 세단뛰기 기술 정량화 및 싱글 암과 더블 암의 이 로움에 연구의 초점을 맞추고 있다 (Allen, King & Yeadon, 2010, 2013Liu & Yu, 2012;Song & Ryu, 2010).…”

“…이러한 분배는 각 국면에서 운동학적 변인인 수평·수직속도 전환 사이의 관 계가 서로 독립적인 관계에 있기 때문에 선수 개개인별로 자 신에 적합한 국면비가 존재하며 (Liu & Yu, 2012;Yu, 1999;Yu & Hay, 1996;Ryu, 2005;Song & Ryu, 2010), 수평·수직 속도 전환 사이의 선형 관계에서의 기울기는 속도 전환계수와 관련이 있으며 이를 근거로 기술 유형을 결정짓는다 (Liu & Yu, 2012;Yu, 1999;Yu & Hay, 1996). 그리고 각 국면 발구 름 동작에서 접지와 이륙 자세가 일정하게 유지된다고 가정할 때 수평과 수직속도 사이의 전환 관계로 선수들의 국면비를 결정할 수 있다고 하였다 (Allen et al, 2013). Table 1.…”