adults use handbags or 
 shoulder bags , which places a load on one hand or one shoulder , respectively1 .
overly heavy bags , inadequate carrying methods , and bag locations 
 distribute the weight inappropriately , which can cause abnormal posture and consequent 
 muscle pain and spinal disorders3 . 
 however , as people are accustomed to carrying bags , they are inclined to neglect problems 
 that are caused by the weight of the bags and how they are carried on the body . if the bag 
 is viewed as a piece of baggage with a certain weight , the effects of its location or weight 
 should be considered .
in particular , as the transport of baggage and the action of walking 
 are correlated , the effects of transporting a bag on walking should be taken into account . 

walking is a complex exercise pattern formed by the effect of neuromuscular , biomechanical , 
 and kinesiological changes that take place over a long period , starting at birth .
when the 
 head , neck , and trunk are aligned normally , the resulting stability and appropriate range of 
 motion ( rom ) allow alternative movements4 . 
 in normal walking , the center of pressure ( cop ) shifts in a regular and symmetric manner , 
 according to whether the direction is up , down , left , or right , and the extremities move in 
 harmony accordingly5 .
the weight , 
 location , and method of carrying a bag cause the physical response of maintaining balance 
 when the location of the weight line changes .
moreover , in moving forward , the body uses an 
 adaptation mechanism in order to rearrange the body segments in an abnormal posture6 .
in addition , a long - term increase in fatigue can create problems with 
 weight distribution and is a direct cause of disorders and diseases7 .
in korea , studies have been undertaken to resolve problems caused by methods of carrying 
 bags and to suggest correct carrying methods .
however , most studies have focused on either 
 elementary school students8 , 9 or bags10,11,12 . 

therefore , the present study was performed to analyze gait changes in healthy women 
 according to their bag - carrying habits and methods , and thereby provide information to help 
 maintain correct posture .
the study 's subjects were 34 women in their 30s who resided in s city and were using the 
 region 's cultural center .
those with orthopedic disorders , neurosurgical disorders , 
 functional or anatomical differences in lower limb lengths , or visual impairment were 
 excluded from the sample .
the research period was from august 1 to september 30 , 2011 . based 
 on the declaration of helsinki ,
therefore , the inclusion criteria specified right - handed 
 participants . of the 34 subjects , 18 ( 21.4  6.5 yrs , 158.3  4.4  cm , 51.1  6.7  kg ) had the 
 habit of carrying bags on their right side , and 16 had the habit of carrying bags on their 
 left side ( 20.3  6.5 yrs , 159.4  6.3  cm , 52.4  5.7  kg ) . the handbag used in this study had a wide rectangular shape ( 33  23  16  cm ) , which korean 
 women favor . as a single - strap bag ,
a previous study14 suggested that a bag 's appropriate weight 
 should be a maximum 10% of its carrier 's weight .
given this , after measuring the average 
 weight of the subjects , a sandbag was inserted into the handbag .
thus , a sandbag weighing 4.6  kg was inserted in the handbag , which 
 weighted 600  g. adults mainly use handbags that are either carried over the shoulder or held in the hand . 
 hence , the subjects were instructed to carry the bag in four ways : in the left hand , over 
 the left shoulder , in the right hand , and over the right shoulder .
when the subjects carried 
 the handbag over the shoulder , they were instructed to adjust the handbag 's length at the 
 level of the iliac crest in the flank6 . a 
 gait analyzer
( walk way mg-1000 , anima co. , japan ) was used to measure the gaits . before the 
 experiment , in order to prevent unnatural movements , the subjects were instructed to do 
 light stretching .
they then did walking exercises three times on the gait analyzer in order 
 to produce natural motions . during the measurements , the subjects wore a comfortable 
 tracksuit and socks without shoes .
they were instructed to begin on the right foot . in order 
 to measure their natural gait while carrying the bags , the participants walked for about 
 three minutes before the measurement procedure , looking forward and naturally swinging both 
 arms . once in each posture , they walked four times , with a 3-minute break between each 
 posture . spss 12.0 was used to process the statistical data on habits and methods of carrying the 
 handbag .
an independent samples t - test was conducted to identify gait differences according to 
 handbag - carrying habits .
a one - way anova was performed to identify gait differences 
 according to handbag - carrying methods .
the results of the analysis of the relation between handbag - carrying habits and methods , 
 showed no interaction . with regard to gait differences according to handbag - carrying habits , 
 statistically significant differences were exhibited in stride length , step length , step 
 width , gait angle , and time ( p<0.01 ) .
no 
 statistically significant changes were exhibited in the stance , swing , and double stance 
 phases ( table 1 ) .
subjects with the habit of 
 carrying bags on their right side revealed relatively larger strides and step lengths , 
 whereas their step widths and gait angles were relatively smaller . therefore , distance 
 variables related to walking distance exhibited differences according to handbag - carrying 
 habits .
the variable of time was found to be shorter in subjects with the habit of carrying 
 bags on their right side , which resulted in an overall faster gait velocity . as a result , in 
 terms of the temporal gait variables ,
only certain variables exhibited differences according 
 to handbag - carrying habits . in terms of gait differences according to handbag - carrying methods , the variables of stride 
 length , step length , step width , gait angle , toe - out angle , time , stance phase , swing phase , 
 and double stance phase showed no statistically significant differences .
this suggested that 
 no differences occurred in both temporal and spatial gait variables according to 
 handbag - carrying methods ( table 1 ) .
the purpose of this study was to provide information about maintaining correct posture 
 while carrying a handbag by identifying appropriate bag - carrying habits and methods .
the 
 methods of carrying a handbag in the hand or over the shoulder were both revealed to have no 
 effects on gait velocity or other gait components .
park 's study15 showed that the pattern of either carrying or holding bags 
 did not influence plantar foot pressure , and no differences in plantar foot pressure were 
 exhibited between backpacks and shoulder bags3 .
the results of that study are in agreement with the present study 's 
 findings that bag - carrying methods do not influence temporal and spatial gait variables . in the present study , compared with subjects that habitually carried bags on their left 
 side , subjects that usually carried bags on their right side exhibited longer stride and 
 step lengths and narrower step widths and gait angles . because increased stride and step 
 lengths led to narrower step widths and gait angles , subjects that habitually carried bags 
 on their right side were likely to have higher levels of stable gait .
the toe - out angle is 
 related to the degree of internal and external rotations of the lower extremities during the 
 stance phase16 .
consequently , carrying a 
 bag with an appropriate weight was revealed to have no influence on the toe - out angle . according to an1 , asymmetric bag loads
in addition , an increase in the 
 load applied to one foot during the stance phase decreases step width and increases cadence . 

kim et al . reported that when subjects walked without a bag , step lengths were found to be 
 longest17 , whereas the longest bag 
 length resulted in the shortest step length .
asymmetric 
 loads vary according to bag - carrying methods , causing instability and relocation of the cop . 
 in response , a mechanism for posture adaptation is activated to maintain physical balance , 
 which subsequently results in posture changes in the trunk and extremities .
when people walk 
 while carrying a heavy bag over a shoulder or in a hand , the foot on the same side has a 
 larger ground reaction force than the opposite foot , thereby increasing asymmetry .
moreover , 
 during walking , this foot requires larger muscular strength , propulsive force , and energy 
 consumption18 .
constant exposure to 
 such asymmetrical loads can also cause physical problems that lead to inadequate posture .
a 
 previous study found that in cases of carrying a bag with a strap on one side and carrying a 
 sports bag designed to be carried on one side , the elevation of the shoulder that supported 
 the strap and the trunk lateral rotation on the opposite side increased2 . in the present study ,
the right - handed subjects who habitually carried bags on their right 
 side had fast gait velocities .
thus , future studies should identify gait changes in subjects while they carry a bag in 
 their dominant hand . in conclusion , this study found that when the bag 's weight was 
 appropriate ( maximum 10% of its carrier 's weight ) , the effects of the carrying method were 
 insignificant .
in other words , only bag - carrying habits had significant effects on gaits . 

therefore , it may be necessary for people to be aware of the negative effects on posture 
 caused by their bag - carrying habits .
   [ purpose ] the purpose of this study was to provide information to help maintain correct 
 posture by identifying gait changes caused by the habits and methods of carrying bags . 
 
 [ method ] the subjects were 34 healthy right - handed women . among them , 18 subjects had the 
 habit of carrying bags on their right side , and 16 subjects had the habit of carrying bags 
 on their left side . 
 the subjects were instructed to walk while carrying a bag , which 
 weighted approximately 10% of the subjects ' average weight , in four different ways ; 
 holding it in the left hand , carrying it over the left shoulder , holding it in the right 
 hand , and carrying it over the right shoulder . 
 the subjects ' gaits were measured using a 
 gait analyzer . [ results ] subjects who habitually carried bags on their right exhibited 
 changes in gait variables related to walking distance . 
 in addition , their gait velocities 
 were relatively faster . 
 on the other hand , differences in temporal and spatial gait 
 variables were not exhibited when the bag was carried using the four methods . 
 [ conclusion ] 
 when the weight of a bag is appropriate , bag - carrying habits had significant effects on 
 gaits . 
 therefore , people who carry bags should avoid the habit of carrying them on only 
 one side . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION