we compared the lumbar repositioning error ( re ) according to different lumbar angles in a 
 flexion pattern ( fp ) subgroup of patients with non - specific chronic low back pain ( nsclbp ) . approximately 85% of this population was classified as having nsclbp , with no radiological 
 change between the 12th rib and the inferior gluteal fold1 . the management approach has been the use of subgroups classified on 
 the basis of pain - provoking postures and movements in nsclbp2 . repositioning error ( re ) is defined as proprioceptive impairment , 
 known to result in poor spinal stability3 . impaired proprioception in positions such as sitting and standing can be related to lbp . in 
 particular , it is associated with flexion direction in the subgroup with pain provoked by 
 lumbar flexion4 . however , few studies have 
 examined re in subjects with flexion - related lbp during the performance of different lumbar 
 flexion angles , as in extension on sitting and standing upright postures . thus , the purpose 
 of this study was to compare changes in lumbar re at different angles while standing and 
 re - standing and sitting and re - sitting in a subgroup of fp subjects with nsclbp . s system5 , 
 6 and was defined as subjects with pain 
 provoked by postures and movement - related flexion of the lumbar spine . in the fp subgroup , 
 symptoms were relieved by movement associated with extension , lordosis of lumbar segments , 
 and the loss of a neutral spine posture due to a flexed spine5 , 6 . the subjects were aged 
 44.78.2  years ( mean  sd ) with a height of 165.45.1  cm , a body weight of 62.37.2  kg , a 
 korean oswestry disability index ( odi ) of 30.04.0% , and a visual analog scale ( vas ) score 
 of 5.51.2 . ethical approval was obtained from the inje university faculty of health science 
 human ethics committee . we used a dual inclinometer ( acumar , lafayette instrument co. , 
 lafayette , usa ) to measure the lumbar re at the main and companion parts ( l1 and sacrum ) . intra - test reliability of the dual inclinometer was 0.90 , and the inter - test reliability was 
 0.85 . the subjects were required to stand upright for 5  s and to hold lumbar flexion angles 
 of 30 and 15 and a lumbar extension angle of 15 for 5  s , followed by return to the 
 starting position . the re of the lumbar spine was defined 
 as the difference in the mean sagittal angles between neutral sitting and re - sitting phases 
 and between the standing and re - standing phases of the task . the spss software ( ver . 12.0 ; 
 spss , chicago , il , usa ) was used for all analyses , and the level of statistical significance 
 was set at 0.05 . one - way repeated - measures analysis of variance and the least significant 
 difference ( lsd ) test as a post hoc pair - wise comparison were used to 
 determine significant re differences among the six tasks . the lumbar re increased significantly with flexion at 30 during sitting . upon sitting 
 upright , the lumbar re between sitting and re - sitting was significantly greater with a 
 flexion of 30 ( 5.13.7 ) than 15 ( 2.03.7 ) or with an extension of 15 ( 1.51.9 ) ( p < 
 0.05 ) . in addition , re while sitting with a flexion of 30 was significantly greater than 
 that between the standing and re - standing positions during flexions of 30 ( 1.91.5 ) and 
 15 ( 0.70.6 ) and an extension of 15 ( 0.80.6 ) ( p < 0.05 ) . upon standing upright , the 
 lumbar re between the standing and re - standing positions during a flexion of 30 was 
 significantly greater than during a flexion of 15 or extension of 15 ( p < 0.05 ) . in our study , lumbar spine re increased in a specific direction while in the sitting 
 position in the fp subgroup . in accordance with previous research5 , 6 , the fp subgroup in 
 this study had a deficit in flexed - toward status while sitting , but this was not apparent 
 while standing . however , while the previous study used lumbar full flexion in the standing 
 position , our study used a flexion angle of 30. the neutral re from 30 of flexion was 
 greater than those from 15 of flexion or 15 of extension while standing , and less than 
 that from 30 of flexion while sitting . the standing position would have added 
 proprioceptive input from other distant receptors , while the adoption of a seated position 
 would minimize other proprioceptive inputs by immobilizing the lower legs and the 
 pelvis7 , 8 . furthermore , this may be due to characteristics of the fp group , 
 where pain is provoked during sitting , whereas the pain tended to be relieved upon 
 standing2 . the results of this study 
 revealed the highest displacement changes between sitting and re - sitting on flexion of 30 
 of the lumbar spine from the upright sitting posture . when spinal structures , such as 
 passive ligaments or active muscles are stretched or flexed during sitting , reflexive muscle 
 activity may be reduced , passive structures may be lengthened , and their tension may be 
 reduced due to unsuitable stretching stimulation from the central nervous system9 . dolan and green10 reported significantly increased lumbar re following 5  min 
 in a slouched posture , but not following a 3-s duration . our study showed increased re 
 immediately while sitting at a flexion angle of 30. we suggest that a higher lumbar flexion 
 angle may have a negative impact on lumbar positioning sense while in the sitting posture 
 than in the standing posture in fp subjects with nslbp . we also suggest that the measurement 
 method for lumbar res would be more effective while sitting using a flexion angle of 30 in 
 fp subjects .
[ purpose ] this study determined the change in lumbar position sense according to lumbar 
 angles in a flexion pattern ( fp ) subgroup of patients with non - specific chronic low back 
 pain ( ncslbp ) . [ subjects ] thirteen subjects with fp low back pain participated . 
 [ methods ] 
 the lumbar repositioning error ( re ) of subjects was measured between a neutral starting 
 position and re - position phases at three angles , in sitting and standing upright 
 positions . 
 [ results ] lumbar re was significantly greater during lumbar flexion at a 30 
 angle in the sitting position than in the other tasks . 
 [ conclusion ] in the flexion - related 
 subgroup , the lumbar re measurement may be a more sensitive evaluation method using a 
 lumbar flexion angle of 30 while in the sitting position , compared with other angles in 
 sitting or standing positions .