COORDINATIONS IN UNLOADED SQUAT JUMPING
Keywords: squat jump, coordination
Abstract8 male athletes performed squat jumps in 5 unloading conditions (using counterweight system) and without unloading. Unloading produced a decrease of impulse duration and an alteration of the subject initial position, with more extended ankle and knee joints angles and a more forward antero-posterior projection of CoM. At toe-off, the ankle angle and the antero-posterior projection of CoM increased while the knee amplitude, the maximal hip torque and power decreased. The total and hip works were also weaker. Greater knee extensors and plantar-flexion forces should have prevented the diminution of performance that should have occured consequently to the alteration of initial and final positions associated to the decrease of impulse duration and knee amplitude. Proximo-distal coordination was modified, suggesting a reorganization of muscle functions.
Coaching and Sports Activities
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