The effects of exercise-induced muscle damage on landing biomechanics vary depending on the type of landing

The present study compared the effects of eccentric exercise and knee localized muscle damage on peak vertical ground reaction force (VGRF) and knee and hip biomechanics between drop landing and drop landing with a subsequent vertical jump. Seventeen athletes with training experience in ground-contact sports at a regional level performed 5 sets of 15 maximal eccentric voluntary contractions of the knee extensors of both legs at 60°/s. VGRF and knee and hip joint kinematics and kinetics were measured 24 h pre- and 48 h post eccentric-exercise. The examination of muscle damage indices included isometric torque, muscle soreness and serum creatine kinase activity. All indices changed significantly and confirmed that muscle damage occurred 48 h following eccentric exercise (p <.05). Peak knee joint flexion significantly increased, whereas peak VGRF, peak internal knee extension moment and peak knee power during absorption phase significantly decreased during drop landing with a subsequent vertical jump (p <.05). The only biomechanical measure that significantly changed during both landing tasks was the peak hip joint flexion (p <.05). Therefore, physically active men display a different landing pattern following eccentric exercise of the knee extensors depending on the type of landing.