Coupling motion between rearfoot and hip and knee joints during walking and single-leg landing.
Level 4 - case-series / case-control
Cross-sectional laboratory biomechanical study in a single group of healthy volunteers without a clinical control group
PubMed 28963938 · doi:10.1016/j.jelekin.2017.09.004
What was done
Kinematics of the rearfoot relative to the shank, knee, and hip joints were analyzed in 22 healthy university students during walking and single-leg landing. Relationships between angular kinematic data were assessed using zero-lag cross-correlation coefficients and coupling angles across joints and tasks.
What was found
During walking, rearfoot eversion/inversion and external/internal rotation correlated strongly with hip adduction/abduction (R=0.69 and R=0.84), whereas correlations with knee kinematics were weaker (R≤0.51; hip correlations significantly stronger, P<0.001). During single-leg landing, most coefficients were strong (R≥0.70) and greater than during walking (P<0.001). Coupling angles demonstrated that hip motion relative to rearfoot motion was greater than knee motion relative to rearfoot motion during both tasks (P<0.001).
Why it matters
These findings suggest that distal rearfoot kinematics couple more tightly with hip mechanics than knee mechanics during dynamic movements. Interventions targeting rearfoot motion may therefore directly influence proximal hip control.
Limits
The study evaluated a small sample of healthy young university students (n=22), limiting generalizability to clinical or athletic populations. Only kinematic correlations were assessed; kinetics, muscle activation, and injury mechanisms were not evaluated.