RESUMO
Objective To study the influence of foot progression angle on tibial shock during running. Methods The normal, toe-in and toe-out gait of fifteen healthy adults was tested during running trials on a treadmill. The differences in tibial shock (impact peak, average loading rate, instantaneous loading rate and maximum tibia acceleration) for runners at different foot progression angles were analyzed to explore the influence of foot progression angle on tibial shock. The changes in sagittal plane trunk angle, strike pattern, stride frequency and step width of runners under three gaits were also compared to explore its possible causes. Results Compared with normal gait, the maximum tibial acceleration of toe-in and toe-out gait was increased by 19.3% and 24.5%, impact peak was increased by 7.6%, average loading rate was increased by 7.9% and 9.5%, instantaneous loading rate was increased by 3.9% and 10-.9%, with significant statistic differences. No significant changes were found in sagittal plane trunk angle, strike pattern, stride frequency and step width. Conclusions Foot progression angle might be an another gait parameter which affected tibial shock during running in addition to other related known gait parameters such as sagittal plane trunk angle, strike pattern, stride frequency and step width，which would provide an important reference for prevention of tibial stress fracture.