pain in the upper trapezius ( ut ) region may be caused by the performance of repetitive 
 tasks or continuous weight on the shoulder1 , 2 . brassieres may be a 
 factor contributing to ut pain in women because the weight of the breast causes the 
 brassiere strap to press on the ut muscle4 , 5 . from their teenage years on , women 
 continuously wear brassieres on a daily basis6 , 7 . in most cases , the brassiere has parallel 
 straps that go over the shoulders from front to back8 . the weight of the breasts causes the parallel straps to cut into 
 the outer shoulder and lengthen the ut muscle , causing pain5 . excessive ut muscle activation resulting 
 from continuous weight on the ut region generates myofascial trigger points that cause 
 pressure pain9 . generally , clinicians 
 concerned about upper trapezius region pain have overlooked whether or not wearing a 
 brassiere leads to upper trapezius region pain . in addition , previous studies have suggested 
 that wearing a brassiere may be a factor contributing to ut region pain due to the weight of 
 the breasts4 , 5 , 
 9 . however , the influence of wearing a 
 brassiere on the muscle activity of ut has not been scientifically proven . therefore , the 
 purpose of the present study was to examine the effect of wearing a brassiere on ut region 
 pain and muscle activity during arm elevation by women . fourteen female with ut region pain aged 25 to 47  years volunteered for this study . inclusion criteria were history of ut region pain for at least 6 weeks and a visual analog 
 scale ( vas ) score > 5 ( severe pain ) at rest . exclusion criteria included past or present 
 neurological pain , cervical spine fractures , radiating pain to an upper limb , and a history 
 of unresolved cancer . the subject s mean age was 34.12  11.62  years , and their mean height 
 and weight were 158.73  4.49  cm and 54.65  6.23  kg , respectively . all subjects read and 
 signed an informed consent form approved by the inje university ethics committee for human 
 investigations prior to their participation in this study . surface electromyography ( emg ) data were recorded using a delsys trigno wireless emg system 
 ( delsys , inc . , emg data were collected from the right side ut muscle ( approximately half the distance 
 between the seventh cervical spinal process and the acromion ) . sampling was performed at 
 1,000  hz , with a bandwidth of 20450  hz , and the root mean square was calculated using emg 
 works 4.0 analysis software ( delsys , boston , ma , usa ) . each maximum isometric contraction maneuver was performed 
 twice for 5  s , and the average muscle activity of the middle 3  s of the two trials was used 
 to normalize the data . pressure pain in the ut region was measured using a baseline 
 dolorimeter ( pain diagnosis and treatment , inc . , great neck , ny , usa ) . the instrument 
 consists of a gauge attached to a hard rubber tip 1  cm in diameter . the dial gauge can be 
 calibrated in kilograms ( kg ) or pounds ( lb ) , with a range of 130  kg or 160 lb . at 
 intervals of 0.25  kg or 0.5 lb . inter - examiner reliability for the baseline dolorimeter is good to excellent 
 ( interclass correlation coefficient= 0.750.89)11 . prior to testing , the subjects were instructed to indicate when the pressure point was 
 painful . to measure the pressure pain in the ut , the subjects were instructed to sit upright 
 on a chair with their feet on the floor looking straight ahead . the examiner stood and 
 measured pressure pain in the middle of the muscle belly between c7 and the acromion . the 
 right and left sides were each measured three times , and the average was calculated . the subjects were 
 instructed to perform shoulder flexion with scaption . during upper limb elevation , the 
 scaption plane was controlled using a vertical bar . subjects were asked to hold the right 
 side shoulder at an angle of 120 degrees for 5 s. the middle 3  s of muscle activity averaged 
 over three trials was used in the analysis . the pressure pain and emg activity were measured with and without wearing of a brassiere in 
 a randomized order . ut muscle activity and 
 pressure pain between with and without wearing brassiere were compared using the paired 
 t - test . statistical analyses were performed using spss ( ver . 17.0 ; spss , 
 chicago , il , usa ) . the emg signal amplitude ( % mvic ) of ut increased significantly ( mean  sd , 50.87  8.92 
 compared to 39.79  7.08 ) when wearing a brassiere compared to the no brassiere condition in 
 the females with ut region pain ( p < 0.05 ) . the ut pressure pain did not differ between 
 two conditions ( p > 0.05 ) . previous studies have suggested that wearing a brassiere may be a factor contributing to ut 
 region pain in women9 , 10 . however , no studies have reported the influence of wearing a 
 brassiere on the emg activity of ut . to the best of our knowledge , this is the first study 
 to demonstrate that a brassiere can increase ut muscle activity during shoulder scaption in 
 women with upper trapezius region pain . our results shows there was a significant 21.7% increase in ut muscle activity when wearing 
 a brassiere . a brassiere transfers the 
 weight of the breast from the pectoral fascia to the ut region , generating a downward force 
 on the shoulder12 . to counterbalance the 
 downward force , greater ut contraction is required to elevate the shoulder , resulting in 
 increased ut muscle activity moreover , shoulder scaption resulted in greater contraction of 
 the ut muscle due to the increased leverage of the arm in this study . sustained and repeated ut muscle contraction would quickly generate ut muscle fatigue , resulting in ut 
 tenderness10 . therefore , when wearing a 
 brassiere , the ut sustains the small weight of the breast with ischemia induced by the 
 brassiere , which would lower the pressure pain threshold of ut . a previous study suggested that brassiere removal during a day ( 24 hours ) was effective at 
 reducing ut and pectoral girdle muscle pain12 . however , in this study , the pressure pain threshold showed no 
 significant difference between the brassiere and no brassiere conditions , because subjects 
 were asked to remove the brassiere for just one minute for no brassiere condition . further 
 study is needed to investigate the effects of brassiere removal during the day on the ut 
 muscle activity and pressure pain threshold of the ut region in women with upper trapezius 
 region pain . the investigation and comparison of various designs of brassiere on the ut 
 muscle activity and pain threshold is also required . a limitation of this study was that we did not measure the breast weight or size of the 
 subjects ; different sizes of breast may affect the pain intensity of ut . also , we did not 
 control for the fit of the brassiere that each participant wore . in conclusion , wearing a 
 brassiere can increase ut muscle activity , so clinicians should consider recommending 
 brassiere removal for as long as possible , or suggest wearing a well - fitting and supportive 
 brassiere when managing women with upper trapezius region pain .
[ purpose ] this study examined the effect of wearing a brassiere on upper trapezius ( ut ) 
 region pain and emg activity during arm elevation by women . [ subjects and methods ] 
 fourteen healthy women were recruited . 
 surface emg data were collected from the ut muscles 
 during arm elevation . 
 pressure pain in the ut region was measured using a baseline 
 dolorimeter . 
 [ results ] the emg activity of the ut increased significantly when a brassiere 
 was worn compared to without . 
 ut region pain showed no significant difference between with 
 and without wearing a brassiere . 
 [ conclusion ] this suggests that wearing a brassiere 
 increases the muscle activation of the ut in women .