Impact of COVID-19 lockdown on the shear wave speed of professional football players hamstring muscles

Abstract

AIM. This work aims to evaluate the impact of COVID-19 lockdown on the shear wave speed (SWS) of hamstrings muscles of professional football players from the Spanish National Football League.

MATERIALS AND METHODS. Shear wave elastography examinations were performed on five elite football players´ hamstrings both before and after COVID-19 lockdown in two positions: a slack position and a tense position. The B- mode ultrasound technique was used to detect fibre disruption or unusual echogenicity in hamstring muscles´ areas with previous injury

RESULTS. A statistically significant increase of SWS was found in the biceps femoris (BF) in the right leg (dominant leg for most players) in both of positions, but no significant difference was found in the other muscles. In the slack position, the BF shear wave speed showed a median increase of 1.64(1.15-1.88) and 1.35(1.25-2.82) folds in the superficial and deep proximal-mid third, respectively. In the tense position, the only statistically significant difference in shear wave speed before and after the COVID-19 lockdown was found in the deep proximal-mid third of BF in the right leg. The BF shear wave speed showed a median increase of 2(1.74-2.43) folds in the deep proximal-mid third in the tense position. There were no statistically significant differences in the number of injuries per football player before and after the COVID-19 lockdown

CONCLUSION. This is the first study to report that a temporary interruption of physical exertion by football players can decrease the stiffness of the BF, which could reduce the number of hamstrings injuries.