The purpose of the study was to examine the plantar loading changes during 5 gradient conditions on a treadmill (-15%, -8.5%, Level, 8.5%, 15%) for 20 participants using the Pedar in-shoe pressure measurement system. The measurement system uses EMED insoles, each consisting of 99 capacitive sensors, sampled at 50 Hz. Data was collected from the last 20 seconds at each gradient condition while participants walked. As the treadmill gradient increased, loading (peak pressure PP and peak force PF) increased in the hallux and 1st metatarsal regions and decreased in the heel region. With negative gradients, loading (PP and PF) increased in the heel region and decreased in the 4th and 5th metatarsal regions.
Grampp et al. (Wed,) studied this question.