Effects of various static calibration postures on knee mechanics during locomotor tasks using statistical parametric mapping analysis

This study aims to examine the effects of various static standing postures on knee biomechanics during dynamic activities, including walking, running, and jumping. Twenty healthy participants (10 males and 10 females; age: 24.7 ± 1.3 years; height: 1.73 ± 0.08 m; weight: 66.5 ± 10.7 kg) performed three distinct static calibration trials: (1) 30° toe-in, (2) 0° neutral posture, and (3) 30° toe-out, before walking, running, and jumping at self-selected speeds. The primary outcome measures included knee joint angles and moments in the sagittal (flexion/extension), frontal (adduction/abduction), and transverse (internal/external rotation) planes. Repeated-measures ANOVA with statistical parametric mapping (SPM) was conducted to evaluate differences across static calibration posture trials. Compared to the neutral (0°) posture, the 30° toe-in posture significantly increased knee adduction angle, external rotation angle, and adduction moment, while reducing knee flexion angle and extension moment during walking, running, and jumping. Conversely, the 30° toe-out posture increased knee abduction angle and internal rotation angle, while decreasing knee adduction moment, relative to the neutral posture. When comparing the toe-out to toe-in postures, the toe-out posture yielded greater knee flexion, abduction, and internal rotation angles, but a reduced adduction moment across all tasks. Static calibration postures significantly affect knee biomechanics, highlighting the necessity for standardized positioning in clinical assessments to prevent obscuring or amplifying clinical outcomes.