Sex differences in pelvis-knee-foot coordination and variability among recreational runners.

Men and women exhibit distinct motor strategies while running, yet their impact on intersegmental coordination remains unclear. The objective of this study was to investigate differences between male and female recreational runners in intersegmental coordination and coordination variability among foot frontal plane (FP), knee sagittal plane (SP), and pelvis FP. Seventy-three recreational runners (31 females; 20-40 years) participated. Intersegmental coordination patterns, coordination variability, and the angles of foot FP, knee SP, and pelvis FP during stance phase were assessed using a motion analysis system and a modified vector coding technique. Groups were compared using unpaired t-tests and statistical parametric mapping (SPM). During early stance, women exhibited higher antiphase distal dominance (AD) compared to men for pelvis FP - foot FP (p = 0.03) and pelvis FP - knee SP (p = 0.05). No significant differences were observed during midstance. In late stance, women demonstrated greater in-phase proximal dominance for pelvis FP - foot FP (p = 0.001), lower in-phase distal dominance (p = 0.02) and AD (p = 0.01) for pelvis FP - foot FP, and lower AD for pelvis FP - knee SP (p = 0.01), compared to men. No differences were found for knee SP - foot FP. SPM revealed no significant differences in coordination variability. This study identified significant sex differences in intersegmental coordination, with women showing greater pelvic dominance and men exhibiting increased foot reliance during propulsion. These findings underscore the importance of sex-specific approaches in optimizing running mechanics and injury prevention strategies. Despite these coordination differences, the similarity in coordination variability between sexes highlights the complexity of biomechanical adaptations in running.