The Biomechanical Effects Of Shoe Midsole Stiffness On Lower Limbs During Jump Movement

BackgroundMetatarsophalangeal joint which is completely covered by sport shoes have hugeeffects in human movement during push off movement.But there is few study talkabout the biomechanical effects of midsole stiffness in metatarsophalangeal, hip, kneeand ankle joint.PurposeThe purpose of this study is to explore the short-and long-term biomechanicaland energetical effects of midsole stiffness in metatarsophalangeal, hip, knee andankle joint. Specific information as follows:(1) To explore the biomechanical and energetical effects of midsole stiffness inmetatarsophalangeal, hip, knee and ankle joint during counter-movement jump andsingle leg jump.(2) To quantify the biomechanical and energetical effects of midsole stiffness inmetatarsophalangeal, hip, knee and ankle joint during counter-movement jump andsingle leg jump after8weeks training by wearing different sport shoes and theeffects of different shoe in sport performance and MPJ maximum isometric flexiontorque.MethodSubjects come from Shanghai University of Sport, specialist in basketball.Testing the countermovement jump and single leg jump by3-D motion capturesystem and3-D force plate is to analysis the biomechanical and energetical effects ofmidsole stiffness in metatarsophalangeal, hip, knee and ankle joint. After the first testsubjects are separated in two random groups which wearing stiffer and softer shoesand do a8weeks training program. Post-test will be taken after training program. Aself-regulating instrument is used to measure MPJ flexion muscle strength.ResultThe stiffer shoes resulted in decreased maximum MPJ flexion velocity; increasedmaximum ankle positive power and ankle energy absorbed&generated. Compared to control group, the8-week training use of shoes with increased MPJstiffness resulted in increased MPJ plantarflexion strength; decreased maximum kneeflexion&extension angle as well as maximum extension velocity; decreasedmaximum MPJ flexion moment, maximum negative&positive power, and energyabsorbed&generated as well as net energy; a potentially efficient situation sincemore MPJ net energy were gained during CMJ; a re-distribution of knee and hip jointkinetics.ConclusionNo effects of stiffer shoes were found in sport performance whether short or longterm. Stiffer shoes can decrease changes of speed in MPJ during countermovementjump and have effects in other lower limb joint. But after8weeks training the stiffershoes increase the MPJ plantarflexion muscle strength and decrease the energy loss inMPJ.