Maximal Strength Testing Using the Long-Lever Hip Adduction Squeeze Test in Youth Elite Football (Soccer) Players: A Four-Week Reliability Study.

Introduction: The long-lever hip adduction squeeze test is a feasible and quick way to measure maximal hip adduction strength, which is associated with groin injury risk. Excellent week-to-week reliability has been established in senior elite football. Youth elite players often engage in physical activities outside of the football academy, which may affect reliability. This study aimed to investigate the week-to-week reliability of the long-lever hip adduction squeeze strength in a youth elite academy football setting using a novel groin strength testing device. Materials and Methods: Seventy-nine youth elite male football players from the U13 to U19 teams of a youth elite football academy were included. During four consecutive weeks, players were tested weekly at the same day each week (match day +2), using a long-lever hip adduction squeeze device with maximal strength recorded. Players who reported groin pain of >2 out of 10 during testing were excluded. Results: No systematic bias was observed between the different testing weeks (p>0.5). Good and consistent relative week-to-week reliability was observed (ICC: 0.916-0.933). Absolute reliability (SEM %) ranged from 7.6-8.6%, with MDCind % and MDCgroup % ranging from 21.2-24 % and 3.3-5.8 %, respectively. Conclusion: Week-to-week measures of long-lever hip adduction strength showed good relative and absolute reliability, and thus can be used in the academy setting to reliably screen for groin injury risk.