" Footwear design characteristics may influence human postural reaction because elevated HH can disturb the ROM of ankle joints and affect human postural control in response to forward translations accordingly ."
bridges of the muscle fibers and disturb the function of calf muscles ultimately ( Timmins et al ., 2016 ). The muscle performance of calf muscles might be affected on account of the increased concentric contraction power in ankle inversion . The increased mediolateral instability would induce the changes in power production owning to the habitual use of narrow heels in experts ( Stefanyshyn et al ., 2000 ). In addition , the muscle performance of calf muscles may be affected on account of the decreased plantarflexion torque and higher reduction on plantarflexion power in experienced HHS wearers ( Farrag & Elsayed , 2016 ). Generally , HHS experience might further influence muscle activities and cognitive processing . However , the ability to integrate the sensory systems in postural control was not altered ; this finding is supported by Xiong ’ s study ( Hapsari & Xiong , 2016 ).
With regard to MCT , the amplitude scaling increased significantly when HH reach 3.9 cm . Although the composite latency was 4.06 % lower in 10.1 HH than in 3.9 cm HH , no significantly delayed postural latency in response to external perturbations was found in our study . Similarly , previous studies have shown no significant difference in postural reaction time when wearing flip-flops , clog style Crocs , and Vibram Five-Fingers ( Chander et al ., 2016 ). Footwear design characteristics may influence human postural reaction because elevated HH can disturb the ROM of ankle joints and affect human postural control in response to forward translations accordingly . When HH reached 3.9 cm , the increased amplitude scaling suggested that HHS wearers may alter motor output strategies to maintain postural stability under perturbations . In the motor output process , the gastrocnemius medialis ( GM ), gastrocnemius lateralis ( GL ), tibialis anterior ( TA ), and vastus lateralis ( VL ) were found to exert more effort when wearing seven cm HHS compared to flat shoes ( Hapsari & Xiong , 2016 ). The threshold of afferent discharge of muscle spindle was raised . The HHS wearers ’ postural control can be affected for the
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