The effect of walking speed on peak plantar pressure.

BACKGROUND Plantar pressure measurements often are used as a tool to evaluate pathologic gait. Previous studies, often done at self-selected walking speeds, have used peak plantar pressure to try to predict ulcer formation, compare surgical outcomes, and evaluate orthotic device efficacy. However, the relationship between walking speed and plantar pressures at specific plantar regions has not been clearly defined. METHODS Twenty normal subjects walked on a treadmill at six speeds (0.75 to 2.00 m/s). In-shoe peak plantar pressure was measured at five plantar regions and compared across the range of speeds. RESULTS Walking speed affected peak plantar pressure differently at the five examined plantar regions. The hallux and heel regions had the highest pressures, which increased linearly with faster speeds. The central and medial forefoot pressures initially increased but plateaued at the faster speeds, while the lateral forefoot had the lowest overall peak pressures, which decreased at the faster walking speeds. Therefore, significant quadratic effects were found at the forefoot. Best-fit regression equations defined distinct pressure-speed relationships at each plantar region (p < 0.0001). CONCLUSION The effect of walking speed on peak plantar pressure varied with plantar region. To achieve more robust peak plantar pressure measurements, walking speed should be controlled. Determining the normal plantar function across a range of speeds can aid in the development of shoes and foot orthoses. The pressure-speed relationships presented in this study can be used as a comparative tool for evaluating the efficacy of clinical interventions for pressure reduction, especially when walking speed changes may confound the outcomes.