Background/Objectives: While restricted dorsiflexion range of motion (DF-ROM) is linked to deleterious sagittal and frontal plane knee and hip kinematics during landing, the literature is conflicted as to whether excessive foot pronation is linked to knee injury. The purpose of this study was to examine the relationship between static foot posture, DF-ROM, and lower extremity biomechanics during a drop-landing task. Methods: Fifteen physically active adults (age: 22.6 ± 2.4 years, height: 1.69 ± 0.08 m, mass: 66.40 ± 9.95 kg) volunteered to participate in this study. Static foot posture was measured by the six criteria of the Foot Posture Index (FPI-6) and DF-ROM was measured using the weight-bearing lunge test (WB-LT). Sagittal and frontal plane kinematics and kinetics of the hip, knee, and ankle were captured using a 3D motion capture system and force plate during a drop-landing task. Results: FPI-6 scores (4.67 ± 2.94) correlated with knee abduction angle at initial contact (1.08 ± 3.30°, r = −0.59, p = 0.02), ankle sagittal plane excursion (39.11 ± 7.67°, r = −0.63, p = 0.01) and knee adduction moment (0.58 ± 0.51 N/kg, r = 0.60, p = 0.017). DF-ROM correlated with knee adduction moment (r = −0.59, p = 0.02). The combination of FPI-6 and DF-ROM accounted for 56% of the variance in knee adduction moment (r = 0.746, p = 0.008). No significant relationships were identified for hip variables (p > 0.05). Conclusions: Participants with a more pronated static foot posture displayed less knee adduction angle at initial contact and decreased ankle sagittal plane excursion. Those with less DF-ROM and a pronated static foot posture exhibited increased maximum knee adduction moment. Foot and ankle structure influence lower extremity biomechanics.
Graham et al. (Sun,) studied this question.