The impact of increasing body mass on peak and mean plantar pressure in asymptomatic adult subjects during walking

INTRODUCTION: The implication of high peak plantar pressure on foot pathology in individuals both with and without diabetes has been recognized. The aim of this study was to investigate and clarify the relationship between increasing body mass and peak and mean plantar pressure in an asymptomatic adult population during walking. METHODS: Thirty adults without any relevant medical history, structural foot deformities or foot posture assessed as highly pronated or supinated, and within a normal body mass index range were included in the study. An experimental, same subjects, repeated measures design was used. Peak and mean plantar pressure were evaluated with the F-Scan in-shoe plantar pressure measurement system under four different loading conditions (0, 5, 10, and 15 kg) simulated with a weighted vest. Pressure data were gathered from three stances utilizing the mid-gait protocol. RESULTS: There were statistically significant increases in peak pressure between the 10 and 15 kg load conditions compared to the control (0 kg) within the heel and second to fifth metatarsal regions. The first metatarsal and hallux regions only displayed statistically significant increases in peak pressure between 15 kg and the control (0 kg). The midfoot and lesser digits regions did not display any statistically significant differences in peak pressure between any load conditions compared to the control (0 kg). The second to fifth metatarsal region displayed statistically significant increases in mean pressure in the 5, 10 and 15 kg groups compared to the control (0 kg). A statistically significant increase in peak pressure between the 15 kg and control (0 kg) group was evident in all other regions. CONCLUSION: The relationship between increasing body mass and peak and mean plantar pressure was dependent upon the plantar region. This study provides more detail outlining the response of peak and mean pressure to different loading conditions than previously reported in the literature. Further research including measurement of temporal parameters is warranted.