Research On The Gait Biomechanics Of "Free Lift Heel" State

Objective: The goal in the project is to study when people in “free toes” condition that silicagel insoles simulating, the human body biomechanics parameters about kinetics and kinematicshave a certain difference compared with the same height high heels. In addition to the elastic buffertrait of silica gel insoles itself, more important is due to the other factors of high heels expect heel.This suggests that the foot injury caused by high-heeled shoes is not all blamed on heel height,some improvement design on shoe materials and sole hardness can reduce the foot harm caused bylift heel. The breakthrough design not only can improve the female foot health but also has a broadmarket prospect. Thus, it can improve the optimization design of high-heeled shoes to makewomen group in a comfortable and beautiful condition at the same time with a pair of healthy feet.Methods: This study selected six women subjects is Ningbo University. Their foot size is all37code. The experimental research objects are four sandals (4.5cm thin heel,4.5cm thick heel,7cm thin heel and7cm thick heel) and silica gel insoles used to simulating “free toes” state.According to the different heel heights, we make different layers of silica gel insoles fixed well to4.5cm and7cm insoles with transparent tape. During the experiment process they will be fixedunder heel, so that the foot lift heel state can at the same height with high-heeled shoes. Namely,the “free toes” and “high heels toes” will be compared and analyzed.(1) The kinetics experiment.This experiment used the German Novel company Emed-pedar series insoles plantar pressuremeasurement system and its analysis software, and concluded plantar kinetics parameters ofparticipants during the natural walking: the peak force(MF), peak pressure (PP) and pressure-timeintegral value (FTI). Then we contrast the values difference between the same height “high heelstoes” and “free toes”.(2) The kinematics experiment. This experiment used the Japanese PhotronFastcam SA3movement speed measurement system and the German SIMI Motion analysissoftware, by which we concluded the changes of ankle joint angle and knee joint angle duringnatural walking of subjects. Last we contrast the changes difference between the same height “highheels toes” and “free toes”.Results:(1) The kinetics experiment. On the4.5cm toes height, the MF and FTI value of“free toes” under the big toe and metatarsal medial area compared with thin heel and thick heelwere significantly decrease; PP value under the big toe area compared with thick heel wassignificantly decrease and compared with thin heel and thick heel were significantly increase. Onthe7cm toes height, the MF, PP and FTI value of “free toes” under the metatarsal lateral area compared with thin heel and thick heel were significantly increase.(2) The kinematics experiment.On the4.5cm toes height, the minimum ankle joint angle during walking of “free toes” comparedwith thin heel and thick heel was decrease, and the ankle joint range compared with thin heel andthick heel increase. The maximum knee joint angle during walking of “free toes” compared withthin heel and thick heel was decrease. On the7cm toes height, the minimum and maximum anklejoint angle during walking of “free toes” compared with thin heel and thick heel were all decrease,and the ankle joint range compared with thin heel and thick heel increase. The minimum andmaximum knee joint angle during walking of “free toes” compared with thin heel and thick heelwere all increase.Conclusions and Suggestions: On the low heel state, it can optimize the plantar pressuredistribution proportion which can reduce the common big toe and first metatarsal injury appears;At the same time, free toes can reduce the limit to ankle activity level on the low heel state andreduce the knee strain degree. On the high heel state, the advantageous aspects for ankle and kneejoint reflect much more obvious. Thus it shows that free toes can reduce the joint injury risk duringhigh-heeled walking. The study suggest that by improving other factors of high heels as the shoestoe, shoes upper and soles can optimize high-heeled shoes health design. So as to reduce the footinjury risk caused by foot lift heel with the heel height. In future, female group could be in acomfortable and beautiful wearing state, at the same time, with a pair of healthy feet.