The Hamstring and ACL Injury Incidence during a Season Is Not Directly Related to Preseason Knee Strength Ratios in Elite Male Soccer Players

Abstract

Background and Objectives: The aim of this study was to identify preseason isokinetic strength differences in the knee flexors and extensors and their ipsilateral/bilateral ratios and, furthermore, to compare the results among players who subsequently overcame a hamstring strain injury (HSI) or anterior cruciate ligament (ACL) rupture during the season and those who did not. Materials and Methods: A total of 134 professional soccer players underwent isokinetic strength assessment at a velocity of 60°·s−1 (knee flexors and extensors) for the dominant and non-dominant lower limb to determine preseason peak torque values and bilateral and ipsilateral strength ratios. Subsequently, the incidence of injuries during the season was recorded, and players were divided into groups according to ACL rupture injuries (n = 10), hamstring strains (n = 10), and a control group of non-injured players who were selected on a random basis (n = 20). A retrospective approach was used to analyze and compare the preseason strength characteristics and whether some variance among groups was relevant among the injured leg and non-injured leg groups. Results: The results of our study show that low-angular velocity preseason testing did not result in a player’s HSI or ACL injury during the season. The difference between the monitored groups ranged from 1.5% to 3%. The comparison showed low evidence for significant differences. Conclusions: An angular velocity of 60°·s−1 within concentric muscle contraction alone was not linked to subsequent injury of the hamstring or anterior cruciate ligament and acted as an insufficient factor of injury risk in adult professional soccer players.

Keywords

• ACL
• football
• hamstring injury
• isokinetic peak torque
• performance
• strength asymmetry