Greater toe grip and gentler

This study investigated the plantar pressure distribution during gait on woodensurface with different slipperiness in the presence of contaminants. Fifteen Chinesemales performed ten walking trials on a 5-meter wooden walkway wearing cloth shoein four contaminated conditions (dry, sand, water, oil). A pressure insole system wasemployed to record the plantar pressure data at 50 Hz. Peak pressure andtime-normalized pressure-time integral were evaluated in nine regions. In comparingwalking on slippery to non-slippery surfaces, results showed a 30% increase of peakpressure beneath the hallux (from 195.6 to 254.1 kPa), with a dramatic 79% increasein the pressure time integral beneath the hallux (from 63.8 to 114.3 kPa) and a 34%increase beneath the lateral toes (from 35.1 to 47.2 kPa). In addition, the peakpressure beneath the medial and lateral heel showed significant 20-24% reductionsrespectively (from 233.6-253.5 to 204.0-219.0 kPa). These findings suggested thatgreater toe grip and gentler heel strike are the strategies to adapt to slippery surface.Such strategies plantarflexed the ankle and the metatarsals to achieve a flat footcontact with the ground, especially at heel strike, in order to shift the ground reactionforce to a more vertical direction. As the vertical ground reaction force componentincreased, the available ground friction increased and the floor became less slippery.Therefore, human could walk without slip on slippery surfaces with greater toe gripAbstract