Jumping for distance: control of the external force in squat jumps

Ridderikhoff, Arne; Batelaan, Jan H.; Bobbert, Maarten F.

doi:10.1097/00005768-199908000-00018

Cited by 40 publications

(37 citation statements)

References 10 publications

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“…The jumper flexes at the hips and knees in a downward countermovement, rotates his body about his feet to the desired amount of forward lean, and then performs an explosive leg extension to project his body outwards and upwards (Ridderikhoff, Batelaan, & Bobbert, 1999). The jumper also uses a coordinated forward and upward swing of the arms to increase his speed during the leg extension phase of the jump (Ashby & Heegaard, 2002).…”

Section: Take-off Speedmentioning

confidence: 99%

“…The take-off force generated by the jumper is not constant, as assumed in the model. The force generated by the jumper changes throughout the take-off because of the changing lengths, moment arms, and contraction speeds of the jumper's muscles (Ashby & Heergaard, 2002;Ridderikhoff et al, 1999). Also, we have no experimental evidence that the force exerted by the jumper is the same for all take-off angles, and our experiments showed that the speed of the jumper's centre of mass at the start of the push-off phase steadily increases at lower take-off angles.…”

Section: Take-off Speedmentioning

confidence: 99%

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Optimum take-off angle in the standing long jump

Wakai

Linthorne

2005

Human Movement Science

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The aim of this study was to identify and explain the optimum projection angle that maximises the distance achieved in a standing long jump. Five physically active males performed maximum-effort jumps over a wide range of take-off angles, and the jumps were recorded and analysed using a 2-D video analysis procedure. The total jump distance achieved was considered as the sum of three component distances (take-off, flight, and landing), and the dependence of each component distance on the take-off angle was systematically investigated. The flight distance was strongly affected by a decrease in the jumper's take-off speed with increasing take-off angle, and the take-off distance and landing distance steadily decreased with increasing take-off angle due to changes in the jumper's body configuration. The optimum take-off angle for the jumper was the angle at which the three component distances combined to produce the greatest jump distance. Although the calculated optimum take-off angles (19-27º) were lower than the jumpers' preferred take-off angles (31-39º), the loss in jump distance through using a sub-optimum take-off angle was relatively small. PsycINFO classification: 4010

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Section: Take-off Speedmentioning

confidence: 99%

Section: Take-off Speedmentioning

confidence: 99%

Optimum take-off angle in the standing long jump

Wakai

Linthorne

2005

Human Movement Science

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“…More specifically, it was of interest to determine to what extent a rotation-extension strategy described by Ridderikhoff et al (1999) for horizontal jumps performed without a countermovement, is adopted in horizontal jumps performed with a countermovement. It was hypothesized that jump direction would be influenced by a combination of body configuration at the beginning of the push-off, as well as the relative activation of bi-articular muscles during the push-off.…”

Section: T He Pu R P O S E Of T H I S S T Ud Y Wa S T O P E R For M Amentioning

confidence: 99%

“…The configuration of the body segments at the start of the push-off has previously been shown to explain how an effective horizontal jump can be obtained using the neural input from a vertical jump (Ridderikhoff, et al, 1999). This strategy (termed rotation-extension) simply involves rotating the centre of mass forward of the feet prior to an explosive leg extension.…”

Section: Differences In Body Configurationmentioning

confidence: 99%

Direction Control in Standing Horizontal and Vertical Jumps

Fukashiro

Besier

Barrett

et al. 2005

Int. J. Sport Health Sci.

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T he pu r p o s e of t h i s s t ud y wa s t o p e r for m a de t a i l e d k i ne mat i c , k i ne t i c , a ndelectromyographic comparison of maximal effort horizontal and vertical jumping. It was of particular interest to identify factors responsible for the control of jump direction. Eight male subjects performed maximal horizontal jumps (HJ) and vertical jumps (VJ) from a standing posture with a counter movement. Three-dimensional motion of the trunk, pelvis, and bilateral thigh, shank, and foot segments were recorded together with bilateral ground reaction forces and electromyographic (EMG) activity from seven right leg muscles. Relative to the VJ, the trunk is displaced further forward at the beginning of the HJ, through greater ankle joint dorsiflexion and knee extension. The activity of the biarticular rectus femoris and hamstrings were adapted to jump direction and helped to tune the hip and knee joint torques to the requirements of the task. The primary difference in joint torques between the two jumps was for the knee joint, with the extension moment reduced in the HJ, consistent with differences in activation levels of the biarticular rectus femoris and hamstrings. Activity of the mono-articular knee extensors was adapted to jump direction in terms of timing rather than peak amplitude. Overall results of this study suggest that jump direction is controlled by a combination of trunk orientation at the beginning of the push-off and the relative activation levels of the biarticular rectus femoris and hamstring muscles during the push-off. simulation model that realistic horizontal jumps may be achieved using the muscle stimulation patterns from a vertical jump by simply rotating the body mass forward in relation to the base of support prior to extending the legs. The authors referred to this as a rotation-extension strategy. Results suggested that the required adaptations to the net joint moments that occur when jumping forward compared to upward can be produced by intrinsic muscle properties alone (ie. stiffness and damping). This simplifies the neural control of tasks such as jumping because the same muscle stimulation is effective, although not optimal, for a range of jump directions.In a comparison of countermovement jumps performed in different directions, Jones and Caldwell (2003) explored hypotheses concerning the role of mono-articular and bi-articular muscles. It was hypothesized that bi-articular muscle activity would be modulated to control the direction of the ground reaction force for jumps in different directions, whereas mono-articular muscle activity would not be affected by jump direction. These hypotheses are based on the idea that bi-articular muscles are activated to tune the distribution of moments amongst joints in order to meet task requirements (Jacobs and Ingen Schenau, 1992), whereas mono-articular muscles are activated when they can contribute positive work at the joint they span (Jacobs, Bobbert & van Ingen Schenau, 1993). While Jones and Caldwell (2003) showed activity of ...

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“…No evidence has been found so far that control of jumping involves trajectory planning. On the contrary, results of experiments on jumping forward suggest that subjects tend to keep their muscle stimulation pattern constant and let the kinematic pattern simply emerge (17).…”

mentioning

confidence: 97%