Impact-induced soft-tissue vibrations associate with muscle activation in human landing movements: An accelerometry and EMG evaluation

Abstract

BACKGROUND: Previous studies have not used neurophysiological methodology to explore the damping effects on induced soft-tissue vibrations and muscle responses. OBJECTIVE: This study aimed to investigate the changes in activation of the musculoskeletal system in response to soft-tissue vibrations with different applied compression conditions in a drop-jump landing task. METHODS: Twelve trained male participants were instructed to perform drop-jump landings in compression shorts (CS) and regular shorts without compression (control condition, CC). Soft-tissue vibrations and EMG amplitudes of the leg within 50 ms before and after touchdown were collected synchronously. RESULTS: Peak acceleration of the thigh muscles was significantly lower in CS than in CC during landings from 45 or 60 cm and 30 cm heights (p < 0.05), respectively. However, the damping coefficient was higher in CS than in CC at the thigh muscles during landings from 60 cm height (p < 0.05). Significant decrease in EMG amplitude of the rectus femoris and biceps femoris muscles was also observed in CS (p < 0.05). CONCLUSION: Externally induced soft-tissue vibration damping was associated with a decrease in muscular activity of the rectus femoris and biceps femoris muscles during drop-jump landings from different heights.