FP14.2 Beyond Morphology: The Influence of Anthropometrics on Squat Biomechanics and Hip-Spine Kinematics in Cam-Type FAI

Abstract ICLA14 - The Extra-Articular Masterclass: Endoscopic Repairs, Ischiofemoral Fixes, and Complex Alignment, Auditorium A (BMCC Level 1), October 9, 2026, 14:00 - 16:00 Background Individuals with symptomatic cam-type femoroacetabular impingement (FAI) exhibit limited deep squat depth and alter sagittal spine-hip kinematics. Although the squat is a fundamental closed-chain movement in hip rehabilitation, performance is significantly influenced by individual anthropometrics (e.g., limb and trunk length). To date, these skeletal proportions have not been accounted for when identifying kinematic deviations in cam-FAI patients compared to asymptomatic controls. Purpose To investigate the relationship between femur-to-tibia ratio, trunk-to-femur ratio, maximal squat depth, and sagittal-plane kinematics during deep squats in symptomatic cam, asymptomatic cam and healthy controls. Methods Eighteen males (27.9 ± 4.3 years, 1.80 ± 0.02 m, 77.6 ± 2.5 kg, 23.7 ± 0.5 kg/m2) were divided into three groups: symptomatic cam patients (n = 6), asymptomatic cam patients (n = 6), and healthy controls (n = 6). Further cohort analysis is ongoing. Femur, tibia, and trunk lengths were measured on EOS biplanar imaging. In addition, femur-to-tibia ratio and trunk-to-femur ratio were calculated. During deep squats, 3D motion capture analyzed squat depth (as % of height) and peak sagittal-plane angles (trunk inclination, pelvic tilt and hip flexion) at the deepest position. Group differences were evaluated using one-way ANOVA and associations were examined using Spearman correlation coefficients. Results In the overall cohort, deeper squats were associated with more hip flexion (rho = 0.488, p = 0.040) and posterior pelvic tilt (rho = -0.878, p < 0.001). Individuals with higher femur-to-tibia ratio showed more trunk flexion (rho = 0.860, p < 0.001). Trunk-to-femur ratio was positively correlated with squat depth. (rho = 0.470, p = 0.049). No statistically significant differences were observed in squat depth or sagittal-plane angles between groups (p > 0.05). Conclusion Beyond morphology and pain, individual anthropometrics significantly influence squat performance and sagittal kinematics. Integrating these skeletal factors is critical to accurately characterize the hip-spine relationship and optimize personalized interventions for young adults with FAI.