IS REARFOOT PRONATION A SHOCK ATTENUATING JOINT ACTION?

Michelle Countryman^1,2, Kristian O’Connor², Joseph Hamill².

¹Fila Sport, Peabody, MA, USA. ²Biomechanics Laboratory, University of Massachusetts, Amherst, MA, USA.

The purpose of this study was to investigate the hypothesis that sub-talar joint pronation (i.e. rearfoot motion) is a shock attenuating mechanism during locomotion. Forty-seven males and 48 females served as subjects by walking/running on a treadmill at 6 different locomotor speeds while instrumented with a tibial accelerometer and a rearfoot goniometer. Correlations were performed between rearfoot and impact shock parameters. The results indicated that peak g was negatively correlated with maximum rearfoot angle (r=-0.35) and positively correlated with total rearfoot motion (r=0.60). However, in both cases, the common variance between the parameters was low. It must be concluded that the actions of rearfoot pronation during locomotion are, at best, a peripheral but not a major shock attenuating mechanism.