Is the foot arch coordinated with the other lower limb joints in walking? What if it is coordinated with other joints in the production of walking progression? We computed the contribution of the sagittal angular position of each joint to the production of pelvic anterior-posterior position and displacement, in gait. We found that, despite its small motion, the MFJC had the 3rd largest contribution to pelvic displacement (17.8%) (similarly to ankle contribution – 18.5%). When the arch flattens, the MFJC contributes to gait forward progression, while when the arch raises, the MFJC contributes to backward displacement.
We also investigated if natural variations in MFJC positions, between different steps, are coordinated with changes in the other joints’ positions, as compensations to keep the normal pelvic positions of gait. We found that, in many parts of the stance phase, the joints are coordinated with the MFJC. And that the MFJC was the joint that participated the longest time in this coordination.
These results show a new way of seeing the couplings of joint movements with foot pronation in gait: they seem to be functional compensations to maintain body progression. These findings may help explain the commonly reported relationships of abnormal foot pronation with orthopedic conditions at the lower limb joints.
Name: Thales Rezende Souza, PhD
Institution: Universidade Federal de Minas Gerais. Graduate Program in Rehabilitation Sciences
Position: Assistant Professor