Weaker lower extremity muscle strength predicts traumatic knee injury in youth female but not male athletes

• Published in: BMJ Open Sport & Exercise Medicine Vol. 3; no. 1; p. e000222
• Main Authors: Ryman Augustsson, Sofia, Ageberg, Eva
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 2017; BMJ Open Sport & Exercise Medicine
• Subjects: ACL; Health Sciences; Hälsovetenskap; Idrottsvetenskap; Medical and Health Sciences; Medicin och hälsovetenskap; muscle strength; Original Research; Physiotherapy; Sjukgymnastik; Sport Science; traumatic knee injury; youth athletes; muscle strength; ACL; traumatic knee injury; youth athletes
• ISSN: 2055-7647; 2055-7647
• DOI: 10.1136/bmjsem-2017-000222

BackgroundThe role of lower extremity (LE) muscle strength for predicting traumatic knee injury in youth athletes is largely unknown.AimsThe aim was to investigate the influence of LE muscle strength on traumatic knee injury in youth female and male athletes.Methods225 athletes (40% females) from sport senior high schools in Sweden were included in this case–control study. The athletes recorded any traumatic knee injury that had occurred during their high-school period in a web-based injury form. A one repetition maximum (1RM) barbell squat test was used to measure LE muscle strength. The 1RM was dichotomised to analyse ‘weak’ versus ‘strong’ athletes according to the median (weakmedian vs strongmedian).Results63 traumatic knee injuries, including 18 ACL injuries, were registered. The majority of injured female athletes were in the weak group compared with the strong group (p=0.0001). The odds of sustaining a traumatic knee injury and an ACL injury was 9.5 times higher and 7 times higher, respectively, in the weakmedian group compared with the strongmedian group in females (p ≤0.011). A relative 1RM squat ≤1.05 kg (105% of bodyweight) was established as the best cut-off value to distinguish high versus low risk of injury in female athletes. No strength–injury relationships were observed for the male athletes (p ≥0.348).ConclusionsWeaker LE muscle strength predicted traumatic knee injury in youth female athletes, but not in males. This suggests that LE muscle strength should be included in injury screening in youth female athletes.