A refined view of the determinants of gait: Significance of heel rise

Objectives: Although the major determinants of gait described by Saunders a nd colleagues have been accepted for more than 40 years, recent investigati ons raise the question of whether the reduction in center of mass (COM) dis placement compared with a compass gait model indeed results from the factor s originally described. We tested the hypothesis that heel rise at the end of stance is a true determinant that can explain a considerable portion of the reduction in COM vertical displacement during walking. Design: Stereophotogrammetric data during walking were collected. A modifie d compass gait model incorporating the effect of heel rise, as compared wit h predictions based on a standard compass model, were used to estimate the isolated effect of heel rise on reducing the vertical displacement of COM, Setting: A gait laboratory. Participants: Thirty able-bodied subjects. Main Outcome Measure: The estimated reduction in COM displacement due to he el rise was compared with the actual reduction in displacement. Results: The estimated effect of heel rise on reduction in COM displacement was 23.4 +/- 7.6mm, whereas the actual reduction in COM displacement was 2 1.2 +/- 6.5mm(difference not significant, paired p = .185), Conclusion: During normal walking, heel rise from foot flat has a considera ble role in raising the height of the COM when it is at its lowest, thus re ducing its overall displacement. Insofar as reduction of COM vertical displ acement may have important energy implications, appreciating the specific g ait parameter of heel rise is key in rehabilitative approaches to improve g ait disability.