low back pain is classified as acute , sub - acute , or chronic according to the duration of 
 symptoms1 .
chronic low back pain is 
 normally consistent back pain experienced for more than 12 weeks2 . more than 80% of the world population experiences
low back 
 pain at least once , and 15% of that 80% suffer from chronic low back pain due to unrecovered 
 symptoms3 .
unbalanced mobilization order among stability muscles and mobility 
 muscles , as well as muscle length , causes low back pain5 . for patients with low back pain
, deep muscle exercise is required to counteract muscle 
 atrophy and damage to the deep muscles2 . 

it was found that patients with low back pain experienced a mobilization delay in their deep 
 muscles , which generates activation and contraction before the movement of the limbs6 . for lumbar region stability , strengthening and
co - contraction of the multifidus and 
 transversus abdominis ( ta ) , which are deep stability muscles , and the erector spinae ( es ) 
 and abdominal muscles , which are superficial stabilizer muscles , is required7 . in recent years
, the trunk stability approach has been widely used as a method of spine 
 treatment , and many efforts have been made to objectively prove the effect . among the 
 exercises for trunk muscle activity of patients with low back pain ,
the effect of ball 
 exercise has been reported to comprehensively improve muscle strength , endurance , and 
 flexibility , as well as strengthen body reflexes , sense of balance and proprioception8 .
in addition , stanton et al.9 reported that the swiss ball exercise is an 
 effective stability exercise for trunk core muscles .
pnf has been recommended for sensory - motor control training , as well as for stimulating 
 lumbar muscle proprioception10 . among the 
 pnf patterns ,
the motions of the sprinter ( sp ) and skater ( sk ) patterns were reported to 
 have the advantages of not only strengthening the muscle due to large - scale movement , but 
 also functional training due to active motor control , the strengthening of coordination , 
 increases in the active range of motion , and the efficient control of movement11 .
this study aimed to determine effective methods for pain reduction through the activation 
 of the ta and the es by comparing lumbar strengthening training using a ball , which is 
 generally carried out along with traditional physiotherapy treatment for lumbar 
 stabilization , and pnf combination patterns12 .
the goal was to increase patients muscle strength , stability , and 
 coordination control ability by inducing isometric contractions in manufacturing workers who 
 had chronic low back pain .
the subjects of this study were 40 adult manufacturing workers from d industrial , located 
 in daegu metropolitan city , who had previously experienced cardiovascular system but not 
 orthopedic illnesses , who currently had no specific exercise plan , and carried out daily 
 living activities experiencing had chronic low back pain .
the participants in this study 
 were told prior to the start of the experiment about the purpose and procedure of the 
 experiment , as well as potential effects of the experiment .
all the participants understood 
 the purpose of this study and provided their written informed consent prior to their 
 participation in the study in accordance with the ethical standards of the declaration of 
 helsinki .
the 
 participants were randomly and equally assigned to a pnf combination pattern group 
 ( experimental group ) and a ball exercise group ( control group ) .
the average age , height , and 
 weight of the experimental group were 34.750.85  years , 174.071.05  cm , and 71.254.59  kg , 
 respectively .
the average age , height , and weight of the control group were 
 34.200.69  years , 172.851.24  cm , and 70.753.81  kg , respectively .
the experimental group 
 performed a combination of sprinter / skater posture in a bridge position , sprinter / skater 
 posture in a side - lying position , sprinter / skater posture in a sitting position , and 
 sprinter / skater posture in a standing position for 15 minutes in parallel with pnf .
the ball exercise group in the 
 control group was told that the femoral region must be parallel to the floor while sitting 
 on the ball , and that their knees should maintain a 90-degree angle , using jandas13 basic principle program .
the 
 ball exercise was done with two 20-repetition sets of pelvic tilts ( anterior / posterior , 
 right / left , circle ) while sitting on the ball .
then , two sets of hip lifts while lying back 
 on the ball were performed , lifting one leg while lifting the hip , lifting the hip while 
 bending the knees , and lifting the hip while bending the knee and lifting one leg for 10 
 seconds . following this , one set of marching
was performed while lying with the chest on the 
 ball and crunching , followed by arching while holding the ball between the calves , moving 
 the body right and left while lifting the legs on the ball , bridging , and right and left 
 stretches while leaning on the ball , for 10 seconds each .
the participants subjectively recorded their 
 pain on a sheet of 10-cm - long paper divided by 10 lines .
pain was rated on a scale of 0 to 
 10 , in which 0 indicated that the participant could not feel the symptom of low back pain 
 and could carry out daily life without any problems , while 10 indicated that the participant 
 could not stand the pain and could not conduct daily living activities at all due to 
 continuous severe pain .
pain measurement was performed prior to the exercises , and again at 
 two weeks , four weeks , and six weeks after the start of the intervention . in order to measure muscle activity ,
the maximal voluntary isometric contraction ( mvic ) of 
 each muscle was obtained by manual muscle testing , and root mean square ( rms ) values of the 
 mvic of each muscle were calculated . the flexcomp infiniti emg ( thought technology ltd . 

canada ) , a surface electromyogram ( emg ) , was used for muscle activity measurement .
muscle 
 activity was measured by attaching surface electrodes 3  cm away from the spinous process at 
 the lateral side for es , and 2  cm from the inferior medial area of the anterior superior 
 iliac spine ( asis ) for ta14 .
the recorded 
 surface emg analog signal was , converted to a digital signal , and then filtered and 
 processed using infiniti software ( v. 3.0 ) on a personal computer . for statistical processing of data in this study , spss
v. 18.0 was used to analyze the data 
 with a its significance level of =0.05 . in order to determine the changes in pain and 
 muscle activity of the pnf and ball exercise groups , repeated anova measurements
were 
 performed and the bonferroni correction was used to compare data between measurement times . 
 in order to find the significance of differences between the groups with regard to muscle 
 activity and pain , the independent t - test was performed .
the pnf combination pattern group and the ball exercise group showed significant reductions 
 of vas over time ( p<0.05 ) ( table 1table 1 .
variation of vas score during the intervention period ( unit : score)pre2 weeks4 weeks6 weekspnf pattern group ( n=20)7.951.004.951.002.850.811.500.69ball exercise group ( n=20)7.851.005.200.833.251.122.100.85 , significant difference between pre and 6 weeks , , 
 significant difference between pnf pattern group and ball exercise group at 6 
 weeks . ) .
after 6 weeks of the intervention , the pnf combination pattern group showed 
 a more significant reduction of vas than the ball exercise group ( p<0.05 ) .
, significant difference between pre and 6 weeks , , 
 significant difference between pnf pattern group and ball exercise group at 6 
 weeks . in the ball exercise and pnf combination pattern groups ,
each group showed muscle activity 
 increases in ta and es over time ( table 
 2table 2 .
variation of transverse abdominal and erector spinae muscles during the 
 intervention period ( unit : % mvic)musclegrouppre2 weeks4 weeks6 weekstapnf pattern ( n=20)33.867.4538.066.2239.916.9242.066.70ball exercise ( n=20)34.507.3140.267.1140.077.4340.727.27espnf pattern ( n=20)50.0615.8951.6913.7053.4615.3156.1015.96ball exercise ( n=20)49.8710.2653.589.0353.929.4155.358.42 , significant difference between pre and 6 weeks , , 
 significant difference between pnf pattern group and ball exercise group at 6 
 weeks . ) , while ta showed no statistically significant difference between the two 
 groups over time ( p>0.05 ) , es showed a statistically significant difference between the 
 two groups over time ( p<0.05 ) .
, significant difference between pre and 6 weeks , , 
 significant difference between pnf pattern group and ball exercise group at 6 
 weeks .
patients with chronic low back pain frequently experience a decrease in lumbar flexibility 
 and a weakening of muscle strength and endurance due to decreased motility . as a result
, low 
 back movement depression can lead to increased pain in patients with chronic low back pain 
 and muscle fatigue . strengthening low back muscles
therefore , this study aimed 
 to determine whether conduct of the pnf combination pattern and ball exercise were effective 
 at increasing trunk muscle activity in patients with chronic low back pain , in order to find 
 an effective method of exercise for chronic low back pain . in this study , low back pain was assessed using the vas in order to determine the effect of 
 the exercise treatment on the subjective pain intensity of patients with low back pain .
the reason for the 
 reduction in pain in both groups was the training of unbalanced trunk muscles , which induced 
 an interaction between the trunk muscles which reduced pain . in a related study , lee et 
 al.16 reported a significant reduction 
 in pain of patients with chronic low back pain after training the patients with a ball , a 
 result consistent with our study result .
kofotolis and kellis17 also reported the reduction of pain in the lumbar muscle of 
 patients with chronic low back pain after a pnf program consisting of static and dynamic pnf 
 programs , a result which was also consistent with our study result .
furthermore , our present 
 study also showed that pain reduction was greater in the pnf combination pattern group than 
 in the ball exercise group after six weeks of training .
the reasons for this are that the 
 pnf combination patterns used a technique that used the limbs to indirectly affect the pain 
 area in a posture which did not cause pain to the patients with low back pain , in order to 
 avoid direct stimulation of the pain area .
in particular , the pnf technique is one that 
 controls the proprioception and sensory - motor functions to reduce pain further .
nachemson et 
 al.18 reported that extensor muscles 
 are more closely related to low back pain than flexor muscles . in this study ,
the pnf 
 combination patterns technique started in a side - lying position , which was followed by a 
 standing position , so the extensors acted as an anti - gravity muscle , thereby strengthening 
 extensor muscle strength to effectively reduce pain .
hodges and richardson19 reported that 
 unbalanced trunk muscles in patients with chronic low back pain should be trained to balance 
 the trunk muscles interactively , and that trunk muscle strength was an essential element for 
 maintaining spinal stability , so that muscle strength becomes be a foundational support for 
 maintaining balance . in that sense ,
the pnf combination pattern and ball exercise groups in 
 our study significantly reduced low back pain through the balanced training of trunk muscles 
 and training induced increase in muscle strength . in a similar study , kofotolis and 
 kellis17 directly applied the pnf 
 technique to the shoulder area of the trunk for four weeks .
they reported that trunk 
 endurance increased significantly by indirectly inducing the motion of the trunk , giving 
 resistance to the limbs . in this study , while muscle activity increased in both the pnf combination pattern ball 
 exercise groups , the pnf combination pattern group showed a more significant increase than 
 the ball exercise group .
this can be explained by the fact that the pnf combination patterns 
 technique concentrated on sprinter and skater patterns , and that trunk muscle activity 
 increased more than in the lumbar stabilization group using ball exercise , which used a 
 combination of isotonic techniques .
accordingly , we anticipate that low back pain would be 
 reduced if the sprinter and skater pnf combination patterns used in this study are applied 
 to patients with chronic low back pain , in order to improve trunk stability .
therefore , our 
 study results can be a clinical foundation for the effectiveness of exercise treatment for 
 trunk muscle stabilization of patients with chronic low back pain .
first , the intensity of the application of the isotonic 
 combination was not uniform when the pnf combination patterns were applied .
also , we did not 
 measure the subjects balance abilities , so the quantitative improvement of balance ability 
 due to improvement of stabilizing muscles could not be presented . in the future
, the 
 limitations of this study can be overcome by demonstrating the appropriate application 
 intensity and proper way of measuring balance ability in order to verify the effectiveness 
 of the pnf combination patterns .
   [ purpose ] the purpose of this study was to compare two methods for the muscle 
 stabilization of the trunk of patients with chronic low back pain . 
 the methods comprised 
 combination patterns of proprioceptive neuromuscular facilitation ( pnf ) and ball exercise . 
 [ subjects and methods ] the subjects were 40 volunteers who had low back pain . all subjects 
 were randomly assigned to either a group which received proprioceptive neuromuscular 
 facilitation or a group which performed ball exercise . 
 measurements were taken four times 
 in total , at pre - intervention , two weeks later , four weeks later , and six weeks later . 
 the 
 main measurement methods used were the visual analogue scale ( vas ) for pain and 
 electromyography ( emg ) for muscle activity . 
 [ results ] vas and emg activity were 
 significantly reduced in the pnf combination pattern group and the ball exercise group . 
 a 
 comparison of the groups showed significant differences . in vas and emg activity ; in 
 particular , the combination pattern group using pnf increased emg activity more than the 
 ball exercise group did after six weeks of intervention . [ conclusion ] 
 this study showed 
 that pnf combination pattern training for six weeks was more effective for patients with 
 low back pain than performing ball exercise . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION