Assessing the Relationship Between Ankle Mobility and Functional Performance During Single- and Double-Leg Squats

Introduction: Sports medicine practitioners often use the overhead deep squat (OHDS) and single-leg squat (SLS) to assess joint mobility, strength, and coordination. Limitations in maximum dorsiflexion capacity during a weight-bearing lunge test (WBLT) may lead to improper form during these squats. To examine this relationship, the Functional Movement Screen (FMS) uses a heel lift during OHDS to determine if ankle mobility is a possible cause of poor form during the movement. Methods: This study investigated the relationship between dorsiflexion during WBLT and kinematics during OHDS and SLS while motion capture data were recorded. Multiple regression analyses assessed the relationship between ankle dorsiflexion (ADF) during WBLT, FMS scores, and lower-extremity kinematics. Statistical significance was set at α ≤ 0.05. Results: For OHDS, a significant interaction and strong relationship between maximum dorsiflexion during WBLT and FMS scores were found ( P < 0.01, R 2 = 0.77). Maximum dorsiflexion during WBLT was also a significant predictor of tibia–trunk ratio ( P < 0.01, R 2 = 0.63) and knee flexion ( P < 0.01, R 2 = 0.70). For SLS, WBLT values significantly predicted ADF ( P < 0.01, R 2 = 0.35). Dorsiflexion was not a predictor of knee valgus in either task. Conclusion: These findings suggest that ADF assessed during WBLT significantly influences sagittal plane mechanics during squatting tasks, with stronger relationships during OHDS, but may not contribute to frontal plane compensation. Practitioners should consider ankle mobility when addressing compromised squat mechanics, especially excessive trunk lean during OHDS.