La Physique du Sport

Abstract : Physics tends to understand the world and to find the laws which govern it. Physics of Sports consists in observing with a physicist’s eye the phenomena which happen on the fields. These fields are wide and this study is built on several points which capture our attention : - records sports : to understand the records of speed or strength sports, we focus on muscle contraction mechanisms. We extract the dynamics of a simple gesture at Bench Press and understand it through simple mechanics laws and microscopic model of muscle contraction. - badminton trajectories : we solve the equations of motion of a particle which undergoes gravity and aerodynamic drag (proportional to the velocity sqaure, for high Reynolds numbers) and extract an analytical expression of the range. At each time the launching velocity is higher than the terminal velocity (which is the constant velocity of vertical falling of the projectile under gravity and drag), one observes a Tartaglia triangular shape of the trajectory. It is the case for most of sports balls, for fireworks, for firemen water jets, for cannonballs... For all these trajectories, the range saturates with the initial velocity : even if you hit stronger, the ball will not go further. We show several applications of this property. For exemple in sport, as there is no use to play on a field which is larger than the useful length, the size of sports fields is bound to be linked to the maximal range of the associated ball, from table tennis to golf. - balls impacts : we study soccer kicks and focus on the way of kicking the ball. The toe poke is said to be more efficient than the push pass. We perform experiments which show that the ball velocity does not depend on the shape of the impactor, but only on the velocity of kicking. We then discuss some ways to enhance the impactor velocity by using joints or elasticity of the launcher.
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Contributor : Caroline Cohen <>
Submitted on : Tuesday, February 10, 2015 - 6:03:41 PM
Last modification on : Thursday, July 4, 2019 - 11:00:05 AM
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  • HAL Id : tel-01115322, version 1

Citation

Caroline Cohen. La Physique du Sport. Mécanique des fluides [physics.class-ph]. Ecole Polytechnique, 2014. Français. ⟨tel-01115322⟩

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