Influences of inversion/eversion of the foot upon impact loading during locomotion

Pronation of the foot is believed to be one of the mechanisms used during locomotion to attenuate the loading experienced by the body at ground contact. The purpose of this study was to quantify the changes in loading induced by modifications to the normal pronation of the foot during walking and running. Impact loading in 10 subjects was determined using ground reaction force and tibial acceleration. The results indicated that impact loading was increased when normal pronation was prevented during running. However, there was no reduction in impact loading when normal pronation was exaggerated. RELEVANCE: Orthotic corrections are commonly prescribed to control excessive foot pronation in patients who experience knee pain. The findings of the present paper demonstrate that pronation modifications can affect the magnitude of the impact experienced by the body during locomotion. It was also found that the loading responses to pronation modifications were not consistent between walking and running. Thus care should be exercised when orthotics that will be used for both walking and running are prescribed. Furthermore, patients should be informed that their orthotics may be activity specific.