Opposing effects of foot-loading strategies on patellofemoral and tibiofemoral joint compression forces during walking.

BACKGROUND

Patellofemoral (PF) and tibiofemoral (TF) joint loading during gait are strongly influenced by sagittal-plane mechanics and muscle force distribution. Individuals with knee disorders often modify foot-loading patterns, yet the effects of such strategies on PF and TF joint compression forces (PFCF and TFCF) during walking remain unclear.

RESEARCH QUESTION: How do forefoot, preferred, and rearfoot weight-bearing walking strategies differentially affect PFCF, TFCF, and knee muscle forces during the stance phase of gait?

METHODS

Twenty-eight healthy adults performed forefoot, preferred, and rearfoot weight-bearing walking. Three-dimensional gait analysis, ground reaction forces, and plantar pressure data were collected. PFCF, TFCF, and muscle forces were estimated via OpenSim musculoskeletal modeling; Time-series differences across stance were assessed using statistical parametric mapping (SPM).

RESULTS

Rearfoot weight-bearing walking significantly increased PFCF (p < 0.001) during mid- to late stance versus forefoot and preferred weight-bearing walking. Conversely, forefoot weight-bearing walking significantly increased TFCF (p < 0.001) during early and mid- to late stance. SPM revealed substantial variations in muscle forces across conditions, with rearfoot weight-bearing walking requiring the greatest quadriceps demand and forefoot weight-bearing walking requiring the greatest plantarflexor force. Knee joint angles did not differ (p > 0.05) across conditions.

SIGNIFICANCE: Foot-loading strategies during walking exert opposing, compartment-specific effects on knee joint loading. Rearfoot weight-bearing walking preferentially increases PFCF, whereas forefoot weight-bearing walking increases TFCF via distinct muscle activation patterns. These findings demonstrate mechanical trade-offs in gait modification and may help inform compartment-specific gait retraining strategies for individuals with knee disorders.