the original purpose of shoes was for safety and comfort of the foot during walking , so in 
 earlier eras of the shoe industry , the primary emphasis was placed on the functional aspects 
 of shoes1 . however , these days , high heels 
 are preferred for fashion , to increase height , or to follow modern trends2 . hence 59% of women wearing high heels wear 
 them for 1 to 8 hours per day3 . some women 
 wear them for more than 10 hours continuously per day4 . as a result , the original function of shoes to protect the foot from the rough surface of 
 the ground , weather , and the environment , and to increase the efficiency of walking has now 
 been replaced by the aesthetic effect of high heeled shoes . they also cause shortening of the achilles tendon , an increase in oxygen 
 consumption , and a decrease in stride length and gait velocity . it is also reported that 
 high heels change the joint mobility of the knees , which can cause degenerative 
 arthritis5 . because the contact surface 
 of high heels on the ground is small , instability of the ankle in addition , high heels with a narrow shoe toe can cause 
 foot deformity and back pain7 and can be a 
 factor in increasing lumbar lordosis8 . furthermore , wearing high heels for an extended period can cause the head and thoracic 
 vertebrae to move towards the back and can reduce the lordosis and pelvic tilting 
 muscles9 . wearing high heels in this regard , lee et al.10 studied the effect of high heels on the 
 paraspinal muscles of healthy persons . he reported that increasing the height of heels 
 causes an increase in the emg amplitude in the back extensor . he also reported that the 
 height of heels has an influence on the tension of the paraspinal muscles . on the other 
 hand , lee and jeong4 stated that even when 
 heel heights are the same , different types of heels can have different heel surfaces 
 contacting the ground . therefore , stability and comfort can differ according to the type of 
 heel attached to the shoe , causing varying effects on the human body . nevertheless , the previous studies on the effects of types of high heels on the cervical , 
 thoracic , and lumbar paraspinal muscles are insufficient . therefore , this study researched 
 the effects of different types of high heels ( specifically the wedge heel , setback heel , and 
 french heel , all at a height of 8cmfor consistency ) , on the muscles surrounding the cervical 
 spine , the thoracic spine , and the lumbar spine . all twenty - eight participants were healthy females ( 19.21.1  years , 159.62.962  cm ) without 
 any previous history of foot deformities , abnormal gait pattern , or musculoskeletal diseases 
 for the previous 5  years . this study complied with the ethical standards 
 of the declaration of helsinki , and written informed consent was received from each 
 participant . generally , high heels are available in various heights and forms according to personal 
 preference or style . the high heels commonly found now in stores include french heels , 
 stacked heels , continental heels , setback heels , cuban heels , pantaloon heels , angle heels , 
 dutch heels , flat heels , and wedge heels11 . in this study , we selected 3 types of high heels that were 
 different in shape and function . those selected for the study were wedge heels , setback 
 heels , and french heels . to measure the muscle activations of the paraspinal muscle surrounding the cervical spine , the thoracic spine , and the lumbar spine during standing while wearing high heels , an emg 
 unit ( keypoint , medtronic , usa ) was used . to reduce measurement errors , in addition , the connecting wires 
 were firmly attached to the bodies of the participants so that noise would not interfere 
 with the emg signals12 . the root mean 
 square ( rms ) was used to examine the value of muscle activation . the following muscles were 
 selected to measure the paraspinal muscle activation : the paraspinal muscle around c6 of the 
 cervical spine , the paraspinal muscle around t7 of the thoracic spine , and the paraspinal 
 muscle around l5 of the lumbar spine . after attaching emg electrodes to the paraspinal muscles and waiting for the subject s 
 breathing rate to stabilize , the muscle activation of each muscle was measured while the 
 subject stood on the ground with bare feet . subsequently , muscle activation during standing 
 while wearing 8-cm - high wedge heels , setback heels , and french heels was measured . muscle 
 activation was measured 3 times , and the mean value was used for analysis . in this study , repeated measure anova was used to examine the effects of types of heels on the paraspinal 
 muscle activation . we also carried out the paired t - test in order to examine differences in 
 the values of muscle activation between each type of heel . we used the spss for windows 
 software ( ver.21 ) for statistical analysis and a significance level of =0.05 . the muscle activation of the c6 paraspinal muscle in the standing position differed 
 significantly with each type of heel ( p<0.05 ) . with bare feet , the value was 146.3 v ; 
 with wedge heels , it was 187.1 v ; with setback heels , it was 202.6 v ; and with french 
 heels , it was 201.2 v . the levels of muscle activation of the paraspinal muscle induced by 
 wedge heels ( p<0.05 ) , setback heels ( p<0.05 ) , and french heels ( p<0.05 ) were higher 
 than that induced by bare feet . but no difference was demonstrated among wedge heels , 
 setback heels , and french heels . in the t7 paraspinal muscle , the muscle activation with 
 bare feet was 135.3 v ; with wedge heels , it was 138.3 v ; with setback heels , it was 167.7 
 v ; and with french heels , it was 162.3 v . although it initially might appear that the 
 levels of muscle activation induced by setback heels and french heels were higher than those 
 induced by bare feet and wedge heels , there was actually no statistical difference . the 
 muscle activation of the l5 paraspinal muscle differed significantly with the type of heels 
 ( p<0.05 ) . with bare feet , it was 206.9 v ; with wedge heels , it was 265.5 v ; with 
 setback heels , it was 310.6 v ; and with french heels , it was 292.3 v . the levels of muscle 
 activation of the paraspinal muscle induced by wedge heels ( p<0.05 ) , setback heels 
 ( p<0.05 ) , and french heels ( p<0.05 ) were higher than that induced by bare feet . but no 
 difference was demonstrated among wedge heels , setback heels , and french heels ( table 1table 1.muscle activation of paraspinal muscles in subjects wearing different types of 
 high heels during standing ( unit : v)barefootwedge heelsetback heelfrench heelcervical*146.392.33187.195.3202.6132.5201.2132.6thoracic135.391.7138.3119.6167.7128.9162.3117.7lumbar*206.9174.0265.5168.7310.6220.7292.3207.7*p<0.05 bare foot < wedge heel , bare foot < setback 
 heel , bare foot < french heel by paired t - test ( p<0.05 ) ) . * p<0.05 bare foot < wedge heel , bare foot < setback 
 heel , bare foot < french heel by paired t - test ( p<0.05 ) , shoes are 
 available with various types of heels . generally , the various types of high heels available 
 in the market are classified by their function . jeong11 divided these heel types into categories and gave the following 
 explanation : first of all , the french heel is shaped so that the front part of the heel is 
 in the shape of korean letter . this shape provides a natural curve aligned with the bottom 
 of the shoe . since the bottom part of the shoe is connected to the heel like a tongue , it 
 can reduce accidents caused by heel breakage or by coming out of alignment with the back of 
 the shoe . the stacked heel generally consists of several layers of leather 5  mm thick 
 stacked together and trimmed to match the shape of the heel . the special characteristic of this heel is that the upper part of the chest of 
 the heel spreads somewhat towards the center of the shoe . the setback heel looks similar to 
 the continental heel , but the surface of the back of the heel is straight , forming a right 
 angle . the cuban heel is similar to the continental heel and is generally found in medium 
 heights , but it is not curved like the continental heel . the pantaloon heel is similar to 
 pantaloon pants : the top lift part of the heel is spread out as it extends to the bottom 
 part of the heel , and the waist line of the heel is curves inward naturally . regarding the 
 angle heel , the surface of the base of the heel is straight until reaching the waist line , 
 and it looks like the shape of korean letter . dutch heeled and french heeled shoes with a 
 reduced height are called low heel shoes . they 
 are usually worn by students or as casual shoes ; their heights vary from 1  cm to 3  cm , and 
 they are available in different forms . wedge heels run from the front of the shoe to the back but are thicker at the 
 heels and narrower at the toes . they are usually worn with casual attire or semiformal 
 dress . due to the modern emphasis on aesthetics and fashion , high heels but as the height of the heel increases , the injury to the body also increases . 
 therefore , a number of research projects examining the effects of high heels on the human 
 body have been performed . hyun and kim13 
 researched the effects of high heels on the lumbar muscles by measuring muscle fatigue while 
 wearing high heels of ( 4  cm , 6  cm , and 8  cm ) and while wearing shoes without heels ( 0  cm ) . their research has demonstrated that the fatigue of lumbar muscles was less serious when the 
 heel was 4  cm high or less . however , a large increase in muscle fatigue was demonstrated 
 when the heel was higher than 6  cm . choi and lee14 stated that as the height of heels increases , body muscles tense to 
 improve body balance , which in turn causes muscle fatigue and pain in the back , shoulder , 
 and neck . in addition , kim et al.15 
 performed research on 28 females in their 20s with a foot size of 235240  mm . their research 
 was performed to examine the change in muscle activation of cervical paraspinal muscles , 
 thoracic muscles , and lumbar paraspinal muscles when walking while wearing functional 
 walking shoes and high - heeled shoes . it demonstrated that the levels of muscle activation of 
 cervical paraspinal muscles , thoracic paraspinal muscles , and lumbar paraspinal muscles were 
 higher when wearing high heels than when wearing shoes with normal heels . bullock - saxton16 mentioned that wearing 
 high heels can change the local sensation in ankle joints , which in turn can cause changes 
 in the feedback system of the central nervous system . these changes can interfere with the 
 strength needed to adjust and adopt appropriate ankle movement , which can cause ankle 
 problems . opila et al.17 stated that the 
 higher the height of the heels and the narrower the surface area of heel that touches the 
 ground , the greater the range of movement of center body mass ( cbm ) at the top , bottom , and 
 sides . some researchers have found that high , narrow heels can cause problems for ankle 
 strategies . so lee and jeong4 researched 
 the effects of heel type ( i.e. heel height and width ) on the change in muscle activity of 
 the lower extremities . their research demonstrated that heel height affects the lumbar and 
 lower extremity muscle activity , whereas the width of the heel does not affect it . jeong11 examined the change in the 
 perpendicular direction of the cbm in regards to types of heels . the results showed that the 
 height of the heel is a significant factor in the change in cbm . hence , summarizing all the results of the researches , we 
 can conclude that height of the heel affects the range of movement of cbm which affects the 
 paraspinal muscle activation , whereas the width of the heel has no effect on it . for that reason we used high heels that were the same height but differed in contact width 
 with the ground to research how they affect the paraspinal muscles . as a result , we could 
 see an increase in muscle activation of the cervical and the lumbar paraspinal muscles when 
 subjects wore the wedge heels , setback heels , and french heels . hence , we can conclude that heel height is a more 
 significant factor than heel width when it comes to changes in the cervical , thoracic , and 
 lumbar paraspinal muscle activation . so , we recommend those who have pain or functional problems in the cervical and lumbar 
 areas not wear high heels . however , because the study examined the change in paraspinal 
 muscle activation during standing while wearing high heels , it does not reflect the effects 
 of high heels when it comes to walking . the study also did not examine the change when 
 walking or standing on slopes . so further research should be done on the use of high heels 
 in subjects walking and standing on slopes .
[ purpose ] this study researched the effects of different types of high heels on the 
 muscles surrounding the cervical spine , the thoracic spine , and the lumbar spine by 
 analyzing muscle activation of the paraspinal muscles during standing while wearing high 
 heels . 
 the high heels were all of the same height : 8  cm . 
 [ subjects and methods ] the 28 
 subjects in this experiment were females in their 20s with a foot size of 225230  mm and a 
 normal gait pattern . to measure the muscle activation of the paraspinal muscles , emg 
 electrodes 
 were attached on the paraspinal muscles around c6 , t7 , and l5 . 
 the muscle 
 activation during standing while wearing 8-cm - high wedge heels , setback heels , and french 
 heels was then measured . 
 the measurements were performed 3 times each , and the mean value 
 was used for analysis . 
 [ results ] the levels of muscle activation of the paraspinal muscles 
 induced by standing on wedge heels , setback heels , and french heels in the cervical and 
 lumbar areas were significantly higher than those induced by standing on bare feet . but 
 there was no significant difference according to the heel types . 
 [ conclusion ] the height 
 of the heels presented a greater variable than the width of the heels on the muscle 
 activation of paraspinal muscles . 
 therefore , wearing high heels is not recommended for 
 those who have pain or functional problems in the cervical and/or lumbar spine .