Body Mass and Foot Dominance Disparities in the Foot Plantar Pressure Parameters of Older Women

Background: We examined the effects of foot dominance and body mass on foot plantar pressures in regular-weight, overweight, and obese older women. Methods: Ninety-six women were divided into the regular-weight group (mean 6 SD age, 68.30 6 4.19 years), overweight group (mean 6 SD age, 69.88 6 3.76 years), and obesity group (mean 6 SD age, 68.47 6 3.67 years) based on their body mass index. The Footscan plantar pressure measurement system was used to assess the dynamic plantar pressures, and parameters were collected from risk analysis, foot axis analysis, single-foot timing analysis, and pressure analysis. Results: Significant within-subject differences were found for local risks of the lateral forefoot and midfoot, minimum and maximum subtalar joint angles, flexibility of the subtalar joint, foot flat phase, as well as the average pressures on toes, metatarsals, midfoot, and lateral heel, with the peak pressures on toes 2 to 5, second metatarsal, fifth metatarsal, midfoot, and lateral heel. The phases of initial contact and foot flat, the average pressures on toes 2 to 5, metatarsals, midfoot, and heels, with the peak pressures on the first to fourth metatarsals, midfoot, and heels, exhibited significant between-subject differences. There was an interaction effect of foot dominance and body mass index on the flexibility of the subtalar joint. Conclusions: The nondominant foot works better for stability, especially when touching on and off the ground. The dominant foot works better for propulsion but is more susceptible to pain, injury, and falls. For obese older women, the forefoot and midfoot are primarily responsible for maintaining stability, but the lateral midfoot and hindfoot are more prone to pain and discomfort.