Normalized Hip and Knee Strength in Two Age Groups of Adolescent Female Soccer Players

Hannon, JP, Wang-Price, S, Garrison, JC, Goto, S, Bothwell, JM, and Bush, CA. Normalized hip and knee strength in two age groups of adolescent female soccer players. J Strength Cond Res 36(1): 207–211, 2022—Limb symmetry strength measures are used for clinical decision-making considering when an athlete is ready to return to sport after anterior cruciate ligament (ACL) injuries. However, changes in bilateral muscle strength occur after ACL injury resulting in potentially altered limb symmetry calculations. Adolescent female soccer players are at increased risk of sustaining ACL injuries. Published age and sex-matched strength values in this population may be of benefit to clinicians to improve clinical decision-making. The purpose of this study was to establish normative hip and knee strength data of both the dominant and nondominant limbs in adolescent female soccer players. Sixty-four female soccer players (ages 10–18) were enrolled in this study. Subjects were divided by age into 2 groups (group 1: 10–14 years; group 2: 15–18 years). Subjects underwent Biodex isokinetic strength testing at 60°·s²¹ and 180°·s²¹ to assess quadriceps and hamstring strength. Isometric hip strength (abduction and external rotation) was measured using a hand-held dynamometer. No significant differences were found between groups on either limb in regards to quadriceps or hamstring strength. No significant differences were found between groups on either limb for hip external rotation strength. Significant differences in hip abduction strength were found between groups on the dominant (group 1: 0.21 6 0.04; group 2: 0.18 6 0.04; p 5 0.014) and nondominant (group 1: 0.21 6 0.05; group 2: 0.18 6 0.05; p 5 0.019) limbs. The results of this study shed light on normative strength values for a high-risk injury population.