| Introduction:High heel shoes(HHS)are one of the most commonly worn shoes in women's daily life.It was reported that 6.2%HHS related injuries happened because of falling.It is well established that long-term use of HHS can shorten the muscle length around ankle joint passively.Muscles around ankle and knee joints can co-contract because of the long-term wearing experience.The injury rate of the lower limb may be increased for the muscle fatigue induced by HHS wearing.Heel height(HH)can interrupt the sensory organization ability in human postural control when HH increases to 7cm.In this process,human use more hip strategy than ankle strategy to maintain postural stability.A study used a dynamic support surface with sinusoidal oscillations to simulate perturbations.No changes have been observed in the effects of HH and HHS wearing experience on human postural stability and functional mobility when under dynamic perturbations.The objectives are:1)to examine the influence of HH on human dynamic postural control and functional mobility;and 2)to explore if there are differences in human postural stability and functional mobility among novices and experienced HHS wearers.Methods:41 healthy females were recruited.They were dichotomized into novices and experienced HHS groups according to the inclusion criteria.Four pairs of shoes with different heel heights(i.e.,0.8cm,3.9cm,7.0cm and 10.1cm)were used in this investigation.Sensory organisation test(SOT),Motor control test(MCT)and limits of stability(LOS)were conducted to measure each participant's postural stability by using Neurocom Balance Manager System(NeuroCom~@Balance Manager~@,Version9.3,Natus Medical Incorporated,USA)EquiTest,while functional reach(FR)and timed up and go(TUGT)tests were performed to measure functional mobility.A visual analog scale was used to measure each participant's perceived stability.The data were shown as mean±standard deviation.Analysis of variance(ANOVA)was conducted to examine the effects of HH(within-subject factor)and HHS wearing experience(between-subject factor)on each outcome measure.SPSS 22.0 software was used for statistic analysis at a significance level of 0.05.95%confidence interval(CI)was determined.Results:1.In novices,the functional reach distance was shorter when wearing 7cm HHS compared with 0.8cm shoes(MD=3.222,95%CI 1.297cm—5.148cm,p=0.001).The TUG completion time was longer when wearing 3.9cm HHS compared with0.8cm shoes(MD=0.653s,95%CI 0.355s—0.951s,p<0.001).In experienced wearers,the experienced HHS wearers achieved longer functional reach distance when wearing 10.1cm HHS compared with 0.8cm shoes(MD=6.342,95%CI3.170cm—8.973cm,p<0.001)and shorter TUG completion time(MD=0.275s,95%CI 0.043s—0.507s,p=0.015).2.The perceived stability decreased when wearing3.9cm HHS compared with 0.8cm shoes in both groups(MD=29.095,95%CI16.705—41.486,p<0.001;MD=15.789,95%CI 5.530—26.049,p=0.001).The experienced HHS wears showed increased perceived stability when wearing 3.9cm,7cm and 10.1cm HHS(p=0.002;p=0.001;p=0.011).3.In both groups,HHS wearers showed increased equilibrium score when wearing 0.8cm shoes compared with10.1cm HHS under eyes closed and standing still condition(MD=2.905,95%CI0.268—5.541,p=0.025;MD=3.400;95%CI 0.253—6.547;p=0.030).The significant effect can also been seen in vison interfered and support surface still condition(MD=3.381,95%CI 0.378—6.384,p=0.022;MD=3.300;95%CI0.330—6.270;p=0.024).The novices used less vision compared with experienced HHS wearers in 10.1cm HHS(MD=6.857;95%CI 1.470—12.244;p=0.008).4.The amplitude scaling increased when wearing 10.1cm HHS compared with 0.8cm shoes in both groups under small backward perturbations(MD=-1.000,95%CI-1.606—-0.394,p=0.001;MD=-1.200,95%CI-2.096—-0.304).5.In novices,the composite movement velocity was lower when wearing 7cm HHS compared with0.8cm shoes(MD=0.595,95%CI 0.029°/s—1.161°/s,p=0.029).The directional control decreased when wearing 7cm HHS compared with 0.8cm shoes(MD=13.714,95%CI 9.443%—17.986%,p=0.001).In experienced wearers group,the composite movement velocity was lower when wearing 10.1cm HHS compared with0.8cm shoes(MD=0.990,95%CI 0.415°/s—1.565°/s,p<0.001).The directional control decreased when wearing 7cm HHS compared with 0.8cm shoes(MD=4.250,95%CI 1.223%—7.277%,p=0.003).Experienced HHS wearers manifested better composite directional control when wearing 10.1cm HHS.(p=0.002).Conclusions:1)The perceived stability and functional mobility were decreased when wearing HHS.HHS wearers used more percentage of vision in maintaining postural stability when HH increased to 10.1cm.The integration of the sensory systems in postural control was disrupted under large perburbations when wearing 10.1 cm HHS compared with 0.8 cm,3.9 cm and 7 cm HHS.2)HHS wearers exhibited different motor control strategy when wearing 3.9cm HHS under dynamic perburbations;2)Experienced HHS wearer had better use of ankle strategy and directional control compared with novices.Also,they perceived better stability in postural control and showed better functional mobility. |
PDF Full Text Request