The difference in distribution of forces between walking and running is compared in ten normal subjects. Our analysis of walking gait demonstrates the smooth progression of force distribution from heel strike through push-off with multiple areas of the foot utilized for balance throughout weight bearing. Running shifts weightbearing to the forefoot as the flexors of the foot decelerate the rate of impact and then provide the propulsive force necessary for push-off. Comparison of walking versus running demonstrates that the average duration of foot contact in ten subjects decreases from 0.47 ± 0.01 to 0.29 ± 0.02 sec. The pattern and rate of progression of weight distribution from one area of the foot to another also changes. The time interval from heel strike to first metatarsal head strike shortens by 75 per cent.

The average duration and progression of forces in these ten subjects was then compared to several patients with either pes cavus, pes planus, or a tibio-fibular synostosis. Alterations in walking and running gait patterns seen on the cholesteric crystals demonstrated abnormal distribution of force consistent with their pathology.