Sex-specific Lower Limb Strength, Flexibility, and Running Biomechanics in Adolescents With and Without Osgood-Schlatter Disease

PURPOSE: To examine sex-specific lower limb strength, flexibility, and running biomechanics in adolescents with and without OSD. METHODS: We conducted a retrospective chart review of 100 adolescents (n=25 each group): females with OSD (age=14.6 ± 1.9 y; body mass index [BMI]=21.3 ± 2.1 kg/m2); males with OSD (age=14.4 ± 1.6 y; BMI=21.7 ± 3.2 kg/m2); females without OSD (age=14.8 ± 2.2 y; BMI=21.7 ± 3.0 kg/m2); and males without OSD (age=14.4 ± 2.2 y; BMI=22.0 ± 4.6 kg/m2). We assessed mass-normalized sagittal and frontal hip strength and sagittal knee strength via hand-held dynamometry, and quadriceps femoris (prone knee flexion) and hip flexor (Thomas test) flexibility. Limb crossover, contralateral pelvic drop [CPD], medial knee displacement, and tibial dominant stride were assessed during treadmill running. Group differences were analyzed using a two-way multivariate analysis of variance (continuous outcomes) and logistic regression (categorical outcomes), covarying for age and BMI. Analyses were performed using SPSS (alpha set at p<0.05). RESULTS: Compared with sex-matched healthy peers, females with OSD had impaired hip abduction strength and a greater propensity for CPD and medial knee displacement, though greater hip flexion strength (p≤0.03; Table). Males with OSD had greater hip and knee sagittal plane strength yet impaired flexibility (p≤0.02; Table). Compared with males with OSD, females with OSD had lower hip and knee strength, greater quadriceps femoris flexibility, and higher odds of frontal plane biomechanical deficits (p≤0.02; Table). CONCLUSION: We observed sex-specific differences in lower limb muscular and biomechanical features in adolescents with OSD, suggesting that clinicians should consider sex-specific rehabilitation strategies for adolescents with OSD.