the structure of the human pelvis permits an upright posture and locomotion on two legs rather than on lore legs like other mammals .
although these structures are well adapted for bipedal locomotion , an upright posture may cause problem .
for instance , lower extremity malalignment leading to overload of the femur and tibia has been considered to be the main cause of cartilage degeneration and osteoarthritis of the knee ( aglietti et al . , 2008 ;
the alignment of lower extremity maintains correct posture of the upper body and prevents the body from pains due to bad posture ( eng and pierrynowski , 1993 ) .
koreans , mostly aged people , are accustomed to sitting - on life style and are disposed to have larger external rotation of hip joint , genu varus of the knee , and inversion of the ankle .
the difference of the life style might have effects on the anatomical alignment of the lower extremity and the function of the lower extremity during walking , and might act as the potential risk factors of the knee and the ankle injury .
the purpose of the study is ( a ) to identify the incidence of each lower extremity alignment deformity and identify the relationship of the incidence between the deformities and ( b ) to identify the effects of physical characteristics ( weight , height , age , and gender ) and residence styles ( sitting - on and standing - up life styles ) on the development of 8 lower extremity deformities ( genu valgus , genu varus , genu recurvatum , heel valgus , heel varus , tibial torsion , femoral torsion , and leg length discrepancy ) .
58 males were collected from standing - up life style and 57 from sitting - on life style .
sixty - seven females were collected from standing - up life style and 41 from sitting - on life style each .
all subjects were screened and individuals were removed from the test if they had medical problems such as lumbago and previous lower extremity fracture . each subject was asked wear pants and shirts only .
the subjects were asked to answer each question on the questionnaire including age , gender , height , weight , dominant arm and leg . also , questions about the residence area , years of residence , style of the house if the house is traditional or modern style , bedding style , table style for meal , toilet style , and sitting style for watching tv are included .
the visual postural examination of the lower extremity was conducted from anterior , posterior , lateral , sitting , and prone positions . from the anterior view , any sign of genu valgus , genu varus , or genu recurvatum was observed . from the posterior view , the observations for heel valgus or heel varus were performed . from the sitting position ,
any sign of tibial torsion or femoral torsion was observed . from the prone position ,
the chi - square analysis was used to identify the difference between the residence styles for each dependent variable .
16.0 ( spss inc . , chicago , il , usa ) and statistical significance was set at p<0.05 for all tests .
58 males were collected from standing - up life style and 57 from sitting - on life style .
sixty - seven females were collected from standing - up life style and 41 from sitting - on life style each .
all subjects were screened and individuals were removed from the test if they had medical problems such as lumbago and previous lower extremity fracture . each subject was asked wear pants and shirts only .
the subjects were asked to answer each question on the questionnaire including age , gender , height , weight , dominant arm and leg . also , questions about the residence area , years of residence , style of the house if the house is traditional or modern style , bedding style , table style for meal , toilet style , and sitting style for watching tv are included .
the visual postural examination of the lower extremity was conducted from anterior , posterior , lateral , sitting , and prone positions . from the anterior view , any sign of genu valgus , genu varus , or genu recurvatum was observed . from the posterior view , the observations for heel valgus or heel varus were performed . from the sitting position ,
any sign of tibial torsion or femoral torsion was observed . from the prone position ,
the chi - square analysis was used to identify the difference between the residence styles for each dependent variable .
16.0 ( spss inc . , chicago , il , usa ) and statistical significance was set at p<0.05 for all tests .
incidence of the lower extremity deviations for men and women according to the residence style was shown in table 2 .
for men , the results of incidence of lower extremity deformity according to the life style showed that the incidence of genu varus was significantly high in standing - up life style compared to sitting - on life style ( chi - square=8.28 ; p=0.004 ) . however , the incidences of heel varus ( chi - square=13.223 ; p=0.004 ) and femoral torsion ( chi - square=19.347 ; p<0.0001 ) were significantly high in sitting - on life style than standing - up life style . for women , the incidences of genu varus ( chi - square=24.18 , p<0.0001 ) , heel varus ( chi - square=15.412 , p<0.0001 ) , and tibial torsion ( chi - square = 6.285 ; p<0.012 ) were significantly high in sitting - on life style compared to standing - up life style ( p<0.05 ) . the odd ratio result for lower extremity deformities for men and women between the life styles are shown in table 3 . for men , the odd ratio result for sitting - on life style against standing - up life style showed 6.6 times significantly high relationship in femoral torsion ( 95% confidence range [ ci ] , 1.6426.47 ) in men . for women ,
there were 3.8 times significantly high relationship in genu varus ( 95% ci , 1.0713.17 ) , 8.8 times in genu recurvatum ( 95% ci , 1.5949.00 ) , and 4.2 times in heel varus ( 95% ci , 1.4711.88 ) in women .
the results of this study show that incidence of genu varus in men was significantly greater in standing - up life style compared to the counterpart . however , the incidence of heel varus and femoral torsion was significantly high in sitting - on life style .
genu varus is commonly observed postural disorders in adolescents ( bell et al . , 2013 ) which is more frequent than genu valgus ( cahuzac et al . , 1995 ) .
this deformity constitutes a risk factor biomechanically for knee osteoarthritis and aggravates it by increasing the load on the medial compartment ( lim et al . , 2008 ;
high incidence of genu varus in standing - up life style group might be explained that traditionally korean people are accustomed to the sitting - on life style rather than standing - up life style even though western life style is stabilized in their current daily life .
significantly high incidence of heel varus and femoral torsion might be due to large external rotation of the hip joint , large varus of the knee , and the large inversion of the ankle joint which is produced from sitting - on life style .
different from their counterpart , korean women experience high incidence of genu varus , heel varus , and tibial torsion in sitting - on life style .
the sitting on the surface of the floor makes the knee joint externally rotated which brings heel varus and tibial torsion .
according to the results , sitting - on life style has close relationship with the incidence of genu recurvatum in men while it has very high relationship with genu varus , genu recurvatum , and heel varus in women .
lack of femoral control might result in excessive adduction and external rotation of the knee ( hewett et al .
 this research was performed to identify the incidence of deformity of lower extremity and to identify the relationship of the incidence between the deformities . 
 once the incidences and relationship are found , next purpose was to find the effects of physical characteristics and residence styles on the development of lower extremity deformities . 
 one hundred fifteen males and 108 females participated in this study . 
 data collecting was performed by questionnaire and visual postural evaluation . 
 the incidence of genu varus was significantly high in standing - up life style compared to sitting - on life style ( chi - square=8.28 ; p=0.004 ) . however , the incidences of heel varus ( chi - square=13.223 ; p=0.004 ) and femoral torsion ( chi - square=19.347 ; p<0.0001 ) were significantly high in sitting - on life style than standing - up life style . 
 the incidences of genu varus ( chi - square=24.18 ; p<0.0001 ) , heel varus ( chi - square= 15.412 ; p<0.0001 ) , and tibial torsion ( chi - square=6.285 ; p<0.012 ) were significantly high in sitting - on life style compared to standing - up life style ( p<0.05 ) . 
 the odd ratio result for sitting - on life style against standing - up life style showed 6.6 times significantly high relationship in femoral torsion ( 95% confidence range , 1.6426.47 ) in men . 