Xiong , 2016 ). It will be worthwhile to detect how sensory systems interact during postural control , and to what extend can HH affect movement strategy and influence human overall postural control accordingly .
HHS experience might be another vital factor that can influence HHS wearers ’ postural stability as well . Previous research has shown significant muscular alterations , such as overwork muscle activities in medial gastrocnemius and peroneus longus , shortened calf muscles , and increased Achilles tendon stiffness after long-term use of HHS ( Cronin , Barrett & Carty , 2012 ; Csapo et al ., 2010 ; Kermani et al ., 2018 ). These muscular accommodations around ankle joints can affect the efficient use of ankle strategies to return the body to equilibrium during standing ( Chien , Lu & Liu , 2014 ; Rahimi et al ., 2017 ; Wan , Yick & Yu , 2019 ). However , Xiong and Hapsari found no significant difference in self-initiated standing balance and functional mobility between experienced HHS wearers and inexperienced HHS wearers , although the experienced group showed higher directional control of COG in LOS ( Hapsari & Xiong , 2016 ). Therefore , whether HHS wearing experience can influence human postural stability and functional mobility remains unclear .
Hence , the current study aims to investigate the effects of HH ( i . e ., 0.8 , 3.9 , 7.0 , and 10.1 cm ) and HHS experience on postural stability during dynamic perturbations , perceived stability , and functional mobility in women . We hypothesized that human postural stability could decrease with increasing HH , and HHS experience could improve performance in postural control and functional mobility test .
Materials & Methods Participants
A total of 41 female participants were recruited from the local university and communities ( 21 inexperienced HHS wearers and 20 experienced HHS wearers ). All participants had a shoe size of EU 36 – 39 and self-reported to be free from lower limb injuries for a minimum of six months prior to the study . Participants with any history of musculoskeletal , cardiovascular , neurological , and vestibular abnormalities were excluded from the experiment . Anthropometrics were measured prior to the experiment ( i . e ., body height , weight , foot length , and arch height ). The measurements of foot length and arch height were taken under two conditions : 10 % and 90 % weightbearing loads ( Zifchock et al ., 2017 ). Arch height flexibility ( AHF ) was defined as the changes in arch height from 10 % to 90 % weightbearing conditions , normalized to 80 % body weight . Experienced HHS wearers were those who had worn narrow-heeled shoes with a minimum HH of four cm more than twice per week and at least eight hours per day for one year . Inexperienced HHS wearers were participants wearing HHS less than once per week ( Hapsari & Xiong , 2016 ; Wan , Yick & Yu , 2019 ). The study was approved by the ethics committee of Shanghai University of Sport ( Number : 2018074 ), and all subjects were provided written consents prior to the experiment .
Experimental shoes
Experimental shoes with HH of 0.8 , 3.9 , 7.0 , and 10.1 cm were used in the study ( Fig . 1 ). All the experimental shoes were
Current Pedorthics | January-February 2022 43