computers now play an increasingly important role in our daily lives , and their use is 
 associated with lower back pain . the sacroiliac joint ( sij ) is a widely described source of 
 low back pain . therapeutic approaches to relieve this pain include the application of a 
 pelvic compression belt ( pcb)1 . researchers have suggested that functional exercises conducted using a pcb have a beneficial 
 effect associated with muscle strengthening2 . pcb are effective for stabilizing pelvic articulation and enable 
 exercises that address coordination and stabilization3 . furthermore , evidence shows that application of a pcb can relieve 
 pain and facilitate neuromuscular performance during rehabilitation exercises in patients 
 with lumbopelvic problems4 . in particular , 
 pcbs effectively alter the activation patterns of hip extensor muscles in females with 
 chronic low back pain during prone hip extension5 . moreover , pcbs offer a conservative measure for the treatment of 
 sacroiliac joint pain and are cheap and considered to be without any adverse side 
 effects6 . in addition , it has been shown 
 that use of a pcb significantly improves health - related quality of life and possibly 
 decreases sacroiliac joint - related pain6 . hammer et al.7 suggested that pcb 
 application is accompanied by altered rectus femoris activity when walking . furthermore , pcb 
 improve postural steadiness7 . however , it 
 is unknown whether pcb alter trunk and lower - extremity muscle activities in healthy adults . therefore , the purpose of this study was to investigate the effects of a pcb on these muscle 
 activities in normal healthy adults . all 
 were given comprehensive information on the study , and all provided written informed consent 
 according to the ethical standards of the declaration of helsinki prior to participation and 
 agreed to participate in the study ( table 
 1table 1.pre- and post - intervention electromyography values of subjects wearing or not 
 wearing a pelvic compression belt ( units : % mvic)without pelvic compression beltwith pelvic compression beltchange valueerector spinae*101.7  8.8 80.9  5.6 20.8  10.9oblique internus abdominis*107.8  20.4 87.0  12.420.8 11.7rectus femoris*93.7  15.977.8  8.0 15.8  17.7long head of the biceps femoris*94.7  17.383.6  11.0 11.1  13.2mean  sd . their average ages , heights , and weights were 21.60  1.08  years , 171.20  
 6.23  cm , and 71.23  8.64  kg , respectively . significant intergroup difference between the gains achieved 
 ( p<0.05 ) the pelvic compression belt ( the com - pressor , optp , minneapolis , mn , usa ) used was an 
 adjustable body belt with four elastic compression bands that provide stabilizing pressure 
 and was designed to allow the amount of compression to be adjusted at targeted compression 
 sites . the pcb was placed below the anterior superior iliac spine ( asis)8 , and stabilizing pressure was applied using 
 the elastic compression bands after confirming the location of the compression site . four surface electromyography signals were processed 
 through the mp150 system when subjects were in the bridge position and transformed into 
 digital signals , which were filtered and processed using acqknowledge software ver . 3.7.3 
 ( biopac systems inc . , goleta , ca , usa ) on a personal computer . a 1,000  hz sampling rate was 
 used for electromyography signals , and their amplified waveform was filtered using a 
 60500  hz band - pass filter and a 60  hz of notch filter . for quantifying collected signals , 
 we used root mean square values9 . in 
 addition , the signals collected from each muscle were normalized versus the maximal 
 voluntary isometric contraction ( % mvic ) . to measure muscle activation at maximal voluntary isometric contraction , after collection of 
 the data for 5 seconds at maximal voluntary isometric contraction for each muscle , the 
 average electromyographic signals as a percentage of mvic for 3 of the 5 seconds , excluding 
 the data for 1 second each from the beginning and end , were used . muscle activation was measured using electromyogram electrodes fixed to areas of muscle 
 fibers and by pressing on muscle parts and following the direction of muscle texture to find 
 the appropriate positions . the locations of the surface electrodes were as follows : ( 1 ) for the elector spinae , 2  cm 
 lateral to the spinous process at the l45 interspace10 ; ( 2 ) for the oblique internus abdominis ( oi ) , in the center of the 
 triangle formed by a horizontal line between the anterior superior iliac spine of the 
 innominate and the umbilicus , midline , and the inguinal ligament11 ; ( 3 ) for the rectus femoris , the midpoint between the 
 upper margin of the patella and asis12 ; 
 and ( 4 ) for the long head of the biceps femoris , the midpoint between the gluteal fold and 
 the knee joint13 . intragroup comparisons of variables before and after the intervention were performed using 
 the paired samples t - test . ibm spss statistics ver . 20.0 ( ibm corp , armonk , ny , usa ) the subjects showed a significant decrease in muscle activation in the erector spinae , 
 oblique internus abdominis , rectus femoris , and biceps femoris while wearing the pcb 
 ( p<0.05 ) ( table 1 ) . this study was undertaken to determine how a pcb affects erector spinae ( es ) , oblique 
 internus abdominis ( oi ) , rectus femoris ( rf ) , and long head of the biceps femoris ( bf ) 
 muscle activation in healthy adults . we observed reduced es , oi , rf , and bf activity with a 
 pcb compared with without a pcb in the bridge position . several possible explanations exist 
 for less muscle activity in abdominal muscles than in core muscles while wearing the pcb . 
 stabilizing the core is a dynamic process of maintaining balance . kaushik et al.14 suggested that the transverse abdominis is 
 the first muscle activated during lower extremity movements , indicating that it is a primary 
 muscle linked to core stability during lower limb movements . in the present study , the 
 decreased oi activity indicated that subjects required less effort to maintain stability 
 when wearing the pcb . nevertheless , kim et al.15 suggested that decreasing the activation of abdominal muscles on an 
 unstable surface using an external support , such as a pcb , is suitable for improving 
 abdominal muscle control and lumbopelvic stability . in a recent study by hu et al.16 , it was found that transverse and oblique 
 abdominal muscles were less active with a pcb in normal subjects because these coordinated 
 muscles are activated to press the ilia against the sacrum , creating a forced closure , and 
 the pelvic belt may have substituted for this stabilizing activity . therefore , it is thought 
 that the use of a pcb with external pelvic compression might have improved pelvic joint 
 stability and altered neuromotor control of the lumbopelvic and thigh muscles . first , the small sample size may have adversely 
 influenced certain variables and impacted results . second , the compression force of the 
 pelvic belt was not controlled , although the belt was adjusted by a skilled physical 
 therapist . furthermore , we recruited healthy adults without a history of low back pain or 
 sacroiliac joint pain , and thus , our findings can not be generalized to other populations . 
 finally , we measured emg activity of the trunk and lower extremity , but this is insufficient 
 to represent muscle force directly . further studies are needed to investigate a more diverse 
 sample of normal healthy subjects .
[ purpose ] the purpose of this study was to investigate the effects of a pelvic belt on 
 the activities of trunk and lower extremity muscles in normal adults . 
 [ subjects and 
 methods ] the subjects were 20 normal individuals without a history of orthopedic problems . 
 the pelvic compression belt ( the com - pressor , optp , minneapolis , mn , usa ) was an 
 adjustable body belt with four elastic compression bands that provide stabilizing pressure 
 and was designed to adjust the amount of force applied and to alter sites of compression . 
 the body belt was placed below the anterior superior iliac spine , and stabilizing pressure 
 was applied to the belt using the elastic compression bands in the bridge position after 
 confirming the site of compression . 
 [ results ] the subjects showed a significant decrease 
 in muscle activation in the erector spinae , oblique internus abdominis , rectus femoris , 
 and biceps femoris while wearing the pelvic belt . 
 [ conclusion ] the use of a pelvic 
 compression belt with external pelvic compression might improve pelvic joint stability and 
 alter neuromotor control of the lumbopelvic and thigh muscles .