D7 Elasticity and Efficiency

Title

Diagnosis of the elasticity of the musculotendinous system measures the ability to store and release elastic energy. Tendon stiffness is estimated by dynamic ultrasonography: the displacement of the myotendinous junction (MTJ) is recorded during progressive isometric contractions with the force measured simultaneously on an isokinetic dynamometer. The slope of the force-elongation curve gives the stiffness k_tend. The stretch-shortening cycle analysis (CEA) compares the height of the static jump (SJ) with the countermovement jump (CMJ) and the reactive jump (DJ): the CMJ-SJ difference quantifies the benefit of the CEA. Leg stiffness (k_leg) is calculated from the Spring-Mass Model data using the GRF and CM kinematics. Tendon hysteresis (energy loss) is estimated from the load-unload loop of the force-elongation curve. Measured variables: MTJ displacement by ultrasound, muscle strength by dynamometry, GRF and kinematics. Determined values: k_tend, k_leg, E_elast, _rec, CEA profit, RSI.

ID:2357