the spine forms a closed kinematic chain through segmental coordination of the upper and 
 lower extremities and the pelvic girdle , and affects the static and dynamic patterns of 
 daily life activities and sports1 , 3 , while also having a direct influence on 
 postural alignment through musculoskeletal connections2 . moreover , the spine adopts a gentle curvature through cervical 
 lordosis , thoracic kyphosis , and lumbar lordosis , which helps to maintain posture by 
 absorbing and dispersing spinal impacts32 . however , if a normal form can not be maintained due to internal and 
 external forces , any force applied to the spine can not be dispersed properly , causing 
 lateral imbalance and accumulation of fatigue in the adjacent muscle which often results in 
 chronic low back pain4 , 5 . when the lumbar region and pelvis are unstable , chronic pain may 
 arise due to repeated motion . moreover , static and dynamic movements may decrease , causing 
 morphological changes in the pelvic muscle segments6 , which in turn could lead to instability that exacerbates spinal 
 deformity and pain in the lumbosacral region7 , 36 . most human activities appear to be unilateral , and asymmetry is observed with dominant 
 neuromuscular activities on the dominant side rather than on the non - dominant side9 . lateral imbalance in the trunk often occurs 
 in many athletes who engage in unilateral actions , and in whom the persistent , asymmetric 
 force causes external deformity near the spine10 . damage which is accompanied by twisting , is enhanced as trunk 
 instability increases along with pressure on the spinal joints11 , 33 . such changes 
 in the interactions between body segments cause instability in the standing posture and 
 become the direct cause of low back pain12 . moreover , from an energy efficiency point of view , the main lower 
 extremity joints , including the pelvic girdle , are closely related to each other , and thus , 
 an abnormal movement pattern in one joint can trigger compensatory action or an abnormal 
 movement pattern in another joint13 , 14 . consequently , there is increasing 
 interest in spinal deformities , and evidence - based clinical methods are needed for the early 
 diagnosis and prevention of musculoskeletal pain in athletes who perform large range of 
 motion ( rom ) movement . this study aimed to obtain basic data regarding the prevention of 
 spinal and pelvic deformities by investigating the spinal shape and muscular function 
 characteristics of imbalance reduction and functional improvement following asymmetric 
 activities . a total of 33 subjects participated in this study , including 14 archers ( 6 males , 8 
 females ) , who generally move unilaterally with 4 or more years of experience , who had spinal 
 and pelvic pain , and 19 individuals in the control group ( 8 males , 11 females ) ( table 1table 1.general characteristics of the subjectsgroupsgendernage ( yrs)height ( cm)weight ( kg)ugmale616.20.4173.73.278.09.9female816.40.9164.35.462.09.1cgmale823.62.2175.04.670.17.4female1122.32.2167.28.152.96.3values are meansd , ug : unilateral group , cg : control group ) . the subjects had no musculoskeletal diseases or neurological problems . all 
 the subjects understood the purpose of this study and provided their written informed 
 consent prior to participation in the study in accordance with the ethical principles of the 
 declaration of helsinki . values are meansd , ug : unilateral group , cg : control group for the spinal structure analysis , as an alternative to radiological examination , a 
 posterior trunk measuring system ( formetric 4d , diers international gmbh , germany ) was used . measurements were taken using the rasterstereography method that involves projecting a 
 halogen light source on the trunk posterior15 . the mean deviations for the accuracy of surface analysis and 
 lateral spinal deviation are 0.15  mm and within 3 , respectively16 . highly reproducible and objective for optimal measurement , the participants took off their top and lowered their bottom to the 
 point where the posterior superior iliac spine could be seen and stood in an upright 
 position approximately 2  m away from the camera . in accordance with the raster principle , the spinous process positions from the 
 center of the spine were established as the following 4 anatomical landmarks : the 7th 
 cervical , sacrum point , and the left and right posterior superior iliac spine . analysis were 
 performed on groups divided according to the spine and pelvic deformity and spinal 
 curves . humac norm testing & rehabilitation ( csmi medical & solution , usa ) was used for 
 measuring the isokinetic muscular function of the trunk . a trunk adapter was connected to a 
 dynamometer for the measurement . in order to prevent joint movement from applying external 
 force to regions other than the lumbar region , a strap and belt were used to firmly hold the 
 area , to enable the exertion of maximum muscle strength . the rom of each joint was 
 restricted by calibrating the rom for each participant , to prevent injuries due to 
 hyperextension or hyperflexion during the measurements . the angle of the lumbar region joint 
 movement was set to the maximum rom at which no pain was felt . a preliminary procedure was 
 performed to reduce any unfamiliarity or uneasiness with the test equipment , and the maximal 
 level of exercise was encouraged during the actual measurement . data were recorded of 3 
 repeats at 60/sec to eliminate any influence of fatigue on the measurements . means and standard deviations were calculated for each variable and 2-way analysis 
 of variance was used to analyze intergroup differences and interaction effects . the results for spinal trunk deformities in the unilateral exercise group and the control 
 group are shown in table 2table 2.comparison of trunk deformityfactorugcgtrunk length ( mm)male468.430.7472.529.0female463.027.3434.424.1trunk inclination ( deg)male2.51.82.11.7female3.82.30.51.5trunk imbalance ( deg)male0.40.80.01.3female0.60.60.51.6values are meansd , ug : unilateral group , cg : control group . * * significant difference between groups ( * * p<0.01 ) . there was a significant difference in the interaction effect only for trunk 
 inclination ( p=0.033 ) . only trunk inclination showed a significant difference ( p=0.008 ) 
 among the main effects of group , while only trunk length ( p=0.033 ) showed a significant 
 difference among the main effects of gender . significant difference between groups and genders 
 ( p<0.05 ) the pelvic deformity analysis results are shown in table 3table 3.comparison of pelvic deformityfactorugcgpelvic obliquity ( deg)male0.36.60.22.4 female1.31.81.72.9pelvic torsion ( deg)male1.54.20.12.1 female1.93.30.51.7pelvic rotation ( deg)male3.43.01.41.5female0.22.21.43.9values are meansd , ug : unilateral group , cg : control group significant difference between genders ( p<0.05 ) . the interaction effects showed no significant difference for any of the 
 variables ( p>0.05 ) . none of the variables showed a significant difference ( p>0.05 ) 
 among the main effects of group , while only pelvic rotation ( p=0.006 ) showed a significant 
 difference among the main effects of gender . values are meansd , ug : unilateral group , cg : control group   significant difference between genders ( p<0.05 ) the analysis of variance results for the spinal curve are shown in table 4table 4.comparison of spinal curvesfactorugcgkyphotis angle ( deg)male41.25.137.05.8female43.26.944.37.0lordotis angle ( deg ) male29.24.130.28.9female32.46.142.65.1values are meansd , ug : unilateral group , cg : control group significant difference between genders ( p<0.05 ) . the interaction effect showed no significant difference in any of the 
 variables ( p>0.05 ) . significant differences were found only for the lordosis angle among 
 the main effects of group ( p=0.019 ) and gender ( p=0.002 ) . values are meansd , ug : unilateral group , cg : control group   significant difference between genders ( p<0.05 ) the results for 60/sec isokinetic trunk muscle function are shown in table 5table 5.comparison of isokinetic strength of trunk 60/secfactorugcgflexors ( nm)male196.35.4222.537.8female148.530.1118.027.9extensors ( nm)male158.815.3240.950.0female130.922.2116.642.4values are meansd , ug : unilateral group , cg : control group * significant difference between groups ( * p<0.05 ) significant difference between genders ( p<0.001 ) significant difference between groups and genders 
 ( p<0.05 , p<0.01 ) . interaction effects showed significant differences in flexion ( p=0.010 ) and 
 extension ( p=0.001 ) muscle strength . among the main group effects , there was a significant 
 difference in the extension muscle strength ( p=0.016 ) , while among the main gender effects , 
 significant differences were found in the flexion ( p=0.000 ) and extension ( p=0.000 ) muscle 
 strength . values are meansd , ug : unilateral group , cg : control group * significant difference between groups ( * p<0.05 )   significant difference between genders ( p<0.001 )   significant difference between groups and genders 
 ( p<0.05 , p<0.01 ) force that unilaterally twists the spine or exercise that is accompanied by rotational 
 forces can lead to concentration of static strength in an improper position and repetition 
 of sudden movements . this can cause spinal and pelvic deformities resulting in pain or 
 deformities , such as abnormal posture17 . athletes experience developmental imbalance due to the disruption of physical balance 
 following repetitive and long - term unilateral activities , and can also show diminished 
 athletic performance due to asymmetric posture18 , 
 19 , 35 . abnormal posture structurally affects the joint tissues and 
 increases pain factors , eliciting restrictions in dynamic movement and rom8 , 20 , 34 . for the collection of basic data 
 regarding truncal muscle strength , and the trunk and pelvic structures related to these 
 abnormal deformities , the study participants were divided into the unilateral group and the 
 control group . as the trunk is responsible for a wide rom of the spinal joints , and because it possesses 
 the center of gravity , stability must be maintained for functional movement21 , 22 . a study of 120 athletes by lee et al.23 showed that unilateral exercise resulted in trunk inclination of 
 2.01.9 in a unilateral group versus 1.41.6 in a bilateral group , while rotational angles 
 of 3.79.8 and 0.13.6 were seen in the unilateral and bilateral groups , respectively . this indicated that the truncal alignment of the bilateral group was more stable , with 
 differences of approximately 0.7 in forward inclination and 3.6 in left rotation between 
 the 2 groups . the truncal alignment was more stable in the bilateral group in this study , as 
 in the preceding study , with trunk inclination differences of 0.4 and 3.2 in men and women 
 of the unilateral group ( men : 2.51.8 , women : 3.82.3 ) and control group ( men : 2.11.7 , 
 women : 0.51.5 ) , respectively . the pelvis basically has a laterally symmetric structure , and because it influences 
 postural control , efforts are required to resolve unilateral imbalance and asymmetry in 
 order to maintain the center of gravity7 , 24 . malalignment refers to a postural anomaly 
 or imbalance in the spinal curvature , and because pelvic deformity causes changes in spinal 
 alignment , pelvic movement is closely associated with postural change25 , 37 . such asymmetry 
 in the pelvis causes the entire body to change into a mechanically deformed structure and as 
 a result , excessive tension in the bones causes tension in the soft tissues . as the 
 musculoskeletal system adapts to the asymmetric structure , it should be given close 
 attention over time26 . the analysis of 
 the pelvic obliquity , torsion , and the rotation angles of pelvic deformity in the unilateral 
 group and the control group revealed there were no intergroup differences in any of the 
 variables , although the unilateral group tended to show a larger change in angle than the 
 control group . when the thoracic kyphosis angle and lumbar lordosis angle of the unilateral and control 
 groups were compared , no significant difference was found in the kyphosis angle , but the 
 lordosis angle showed statistically significant main effects of group ( p=0.019 ) and gender 
 ( p=0.002 ) . these results were a similar to those reported by another study27 that showed that the lumbar region is 
 connected to the sacral region forming the lumbosacral region , which is directly involved in 
 the formation of spinal curvature and pelvic alignment , and can have a direct impact on low 
 back pain when there is asymmetry . repeating unilateral exercise over a long period of time can lead to a change in the pelvic 
 position due to imbalances in the muscle length and strength , and asymmetric muscle 
 strength , in particular , can be the cause of musculoskeletal injuries28 . to confirm the findings of these previous studies , a 
 comparison of the isokinetic muscular functions between the unilateral and control group was 
 performed in this study . a significant difference was found in the interaction effects of 
 the flexor and extensor muscles , showing that muscular factors do play a role in unilateral 
 exercise . in particular , statistically significant main effects of group ( p=0.016 ) and 
 gender ( p=0.000 ) were found for the extensor muscle strength of the unilateral group ( males : 
 158.815.3 nm , females : 130.922.2 nm ) and the control group ( males : 240.950.0 nm , females : 
 116.642.4 nm ) . the importance of core exercise with the goal of enhancing coordination between postural 
 movement , muscle strength , and balance around the lumbar region has been being 
 emphasized29 , 30 . the strengthening of the muscles near the lumbar region should 
 help to regulate functional stability and improve muscle strength and function29 , 31 . therefore , the basic data obtained in this study can be used to help 
 develop a strategic exercise program for improving unilateral movement and malalignment of 
 the spine and pelvis .
[ purpose ] the purpose of this study was to collect basic data regarding the prevention of 
 spinal and pelvic deformities by investigating the spinal shape and muscular function 
 characteristics of imbalance reduction and functional improvement following asymmetric 
 activities . 
 [ subjects and methods ] the subjects were 14 archery athletes who mostly 
 perform unilateral motion with spinal and pelvic pain , and 19 healthy subjects . 
 all the 
 participants were evaluated using spinal structure analysis and for 60/sec isokinetic 
 muscular strength of the trunk . [ results ] between the two groups , 
 there were significant 
 differences in the interaction effect of trunk inclination deformities , and flexor and 
 extensor 60/sec isokinetic muscular strength of the trunk . 
 also , the main effects of 
 gender comparison showed significant differences in the trunk inclination deformities , 
 pelvic rotation deformities , lordosis angles , and flexor and extensor 60 /sec isokinetic 
 muscular strengths of the trunk . 
 [ conclusion ] the basic data obtained in this study can be 
 used to help develop a strategic exercise program for improving unilateral movement and 
 malalignment of the spine and pelvis .