one of the goals of occupational therapy is to help improve the performance of functional 
 tasks in daily life1 . in particular , hand 
 and upper extremity activities play an important role in tasks of daily living such as 
 dressing , using a keyboard , eating and so forth2 .
one of the important systems involved in functional tasks of the 
 hand and upper extremity is the mobility of the wrist .
the wrist uses 
 various movements such as flexion , extension , ulnar deviation , and radial deviation ; 
 pronation and supination may also be used in coordination with the elbow joint4 .
the complicated structure and high mobility of the wrist often results in various types of 
 disorder .
wrist joint restriction affects the movement of other joints and causes subsequent 
 problems such as pain .
such problems affect the upper extremity functional activities , which 
 are important goals of occupational therapy .
hence , it is necessary to objectively evaluate 
 the changes in mobility that might take place due to wrist joint restriction during upper 
 extremity functional activities .
the % isolation method can be implemented to examine the pattern of muscle changes due to 
 wrist joint restriction .
since muscle activation may result from reflex activity and fatigue 
 as well as muscle contraction5 , measuring 
 the changes in % isolation of muscles demonstrate how wrist joint restriction changes muscle 
 patterns during upper extremity functional activities .
this study measured the % isolation in upper extremity functional movements related to wrist 
 joint restriction in order assess changes in mobility of the shoulder , forearm and 
 wrist .
the purpose and procedure of the study were fully explained to students at s college , 
 suncheon , jeonnam .
we then included 20 individuals ( 15 women and 5 men ) in the study who 
 agreed to participate in the experiment and signed the consent form .
the chosen subjects 
 were all right - handed , and had neither congenital malformation of the upper extremity nor 
 past functional disorder of the wrists or upper extremities .
they had no medical history in 
 terms of orthopedics , neurology , or pathology .
all the participants read and signed an 
 informed consent form , and the inje university ethics committee for human investigations 
 gave ethical clearance prior to their participation .
this study was performed from february 
 25 , 2012 to march 10 , 2012 .
milan , italy ) , a surface wireless electromyography system was 
 used to measure muscle activation .
it has eight electromyogram ( emg ) channels and uses wi - fi 
 technology for wireless data transmission . to examine the muscle activation with and without 
 wrist joint restriction
, electrodes were attached to the upper trapezius , middle deltoid , 
 biceps brachii , triceps brachii , flexor carpi radialis , and extensor carpi radialis6 . in attaching the surface electrodes ,
the 
 procedures used by cram , kasman and holtz7 
 were adopted at the electrode locations .
hair was removed using a razor blade to minimize 
 skin resistance to electromyographic signals , and the area was washed with disinfectant 
 alcohol twice or three times to remove the horny layer .
the wrist orthosis used for wrist joint restriction was a commercially available , portable , 
 short - wrist orthosis ( sp-872 ) which is used to minimize wrist joint movement to prevent and 
 heal pains generated by various wrist disorders ( special protectors co. , inc .
this study employed manipulation activities that directly involve the wrist joint in the 
 manual function test ( mft ) to evaluate upper extremity functional activities .
mft is a 
 standardized tool that was developed to evaluate damaged motion functions of the upper 
 extremity and objectively analyze the recovery process8 , and it is the most frequently used tool of its kind in korea9 .
the evaluation order and instructions were 
 based on the standardized method of the mft .
the % isolation indicates the role of each muscle as a percentage of the total activity of 
 all the muscles used in the task .
for example , if the % isolation value of the upper trapezius was 100% , it would mean 
 that the other muscles did not work at all during the task .
spss 12.0 version was used for the statistical processing for the data analysis in this 
 study .
wilcoxon s test was employed to analyze changes in % isolation between with and 
 without wrist joint restriction in the mft tasks .
in the grasping task , changes in % isolation of the muscles were shown between with and 
 without wrist joint restriction ( table 
 1table 1 . % isolation for the grasping task ( unit : % isolation)musclewithout restrictionwith restrictiongraspingupper trapezius*35.5740.93middle deltoid11.4911.95biceps brachii6.906.68triceps brachii6.806.64extensor carpi radialis*22.7515.19flexor carpi radialis16.4918.61*p<0.05 ) . without wrist
joint restriction , the % isolation of the upper trapezius was 
 35.57  12.21% , and it increased significantly to 40.93  19.78% ( p<0.05 ) with wrist 
 restriction .
in contrast , the % isolation of the extensor carpi radialis decreased 
 significantly from 22.75  11.39% without wrist joint restriction to 15.19  7.04 with wrist 
 joint restriction ( p<0.05 ) . in the pinching task
, changes in the % isolation of muscles 
 were observed between with and without wrist joint restriction ( table 2table 2 .
% isolation for the pinching task ( unit : % isolation)musclewithout restrictionwith restrictionpinchingupper trapezius*25.2839.77middle deltoid13.9313.57biceps brachii6.046.35triceps brachii9.949.57extensor carpi radialis*17.038.8flexor carpi radialis27.7821.94*p<0.05 ) . without wrist
joint restriction , the % isolation of the upper trapezius was 
 25.26  20.06% , whereas with wrist joint restriction , it significantly increased to 39.72  
 32.69% ( p<0.05 ) .
in contrast , the % isolation of the extensor carpi radialis without wrist 
 joint restriction changed significantly from 17.03  8.17% to 8.84  5.16% with wrist joint 
 restriction ( p<0.05 ) . in the carrying a cube task , there were changes in the % isolation of the muscles between 
 with and without wrist joint restriction ( table 
 3table 3 .
% isolation for the carrying a cube task ( unit : % isolation)musclewithout restrictionwith restrictioncarrying a cubeupper trapezius*24.7939.28middle deltoid*7.7513.29biceps brachii7.996.94triceps brachii*10.915.93extensor carpi radialis*18.8812.2flexor carpi radialis29.6822.06*p<0.05 ) . without wrist
joint restriction , the % isolation of the upper trapezius was 
 24.76  16.19% , and it increased to 40.25  28.17% in the presence of wrist joint 
 restriction .
in contrast , the 
 % isolation of triceps brachii , extensor carpi radialis , and flexor carpi radialis changed 
 from 10.91  11.71% , 18.88  8.02% , and 29.68  18.16% , respectively , in the absence of 
 wrist joint restriction to 5.93  4.18% , 12.50  5.33% , and 22.09  16.66% , respectively , in 
 the presence of wrist joint restriction .
the decreases were statistically significant 
 ( p<0.05 ) . in the peg - board task , there were changes in the % isolation of muscles between 
 with and without wrist joint restriction ( table 
 4table 4 .
% isolation for the peg - board task ( unit : % isolation)musclewithout restrictionwith restrictionpeg - boardupper trapezius31.9341.82middle deltoid11.2313.47biceps brachii6.547.75triceps brachii5.894.39extensor carpi radialis*18.4813.96flexor carpi radialis*25.9318.61*p<0.05 ) . without wrist
joint restriction , the % isolation of the extensor carpi 
 radialis was 18.48  8.27% ; this changed to 13.96  5.64% with wrist joint restriction .
the 
 % isolation of the flexor carpi radialis changed from 25.93  19.58% without wrist joint 
 restriction to 18.61  12.89% with wrist joint restriction .
in the grasping , pinching , and peg - board tasks , % isolation of the upper trapezius increased 
 significantly . in the carrying a cube task ,
this is in line with the results of various other studies , 
 which showed that restricted wrist joints increase shoulder movement and muscle fatigue11,12,13 .
mobility of the elbow and hand joints is 
 essential for the effective use of the hand , as well as the stability of the shoulder and 
 elbow joints14,15,16 .
thus , it is thought that 
 wrist joint restriction significantly decreases the stability of the shoulder joints . in the grasping and pinching tasks ,
finger flexors 
 include extrinsic muscles extending from the forearm as well as intrinsic muscles within the 
 palm17 . in the grasping and pinching 
 tasks
, the wrist creates a flexion phenomenon because the finger flexor ligaments contract 
 with the finger flexor18 . in this 
 process
, the wrist extension muscles are activated to resist wrist flexion in order to 
 maintain wrist stability19 .
thus , it is 
 thought that wrist joint restriction significantly decreases the % isolation of the wrist 
 extension muscles when grasping and pinching motions are carried out . in the carrying a cube task ,
in particular , the triceps brachii showes increased 
 muscle activity with pronation of the forearm21 ; for example , picking up and holding objects above a desk , requires 
 pronation of the forearm at 459522 . in 
 other words ,
forearm pronation increases the muscle activity of the triceps brachii , and 
 wrist joint restriction results in restricted pronation ability of the forearm . as a result , 

shoulder abduction and elevation increases , whereas the % isolation of the triceps brachii 
 decreases .
first , the study was conducted with healthy 
 subjects , not persons with wrist joint restriction .
disorders that may cause wrist joint 
 restriction pose other risks in addition to wrist joint restriction alone .
second , this 
 study was limited to subjects who were in their 20 s , and biomechanics may change with 
 age23 .
the fact that disorders of the 
 wrist might affect different age categories was not considered in this study .
one of the major factors that may affect wrist joint restriction is wearing an orthosis .
a 
 wrist orthosis is frequently used to provide wrist stability to those with various 
 musculoskeletal system disorders .
it is also indicated that compensation frequently occurs 
 in relation to the use of wrist orthoses .
since those with musculoskeletal system disorders 
 such as arthritis , fracture and carpal tunnel syndrome can return to their daily routine 
 with the aid of an orthosis , it is necessary for the wearers to learn how to manage 
 compensation by themselves .
the results of this study may be used as a treatment and 
 education tool , as they provide information on changes in muscle patterns and compensation 
 related to functional activities .
using such information , therapists can predict whether 
 mobility should be facilitated or restricted in order to help and improve the quality of 
 life of those with wrist joint restriction through treatment and educational sessions .
   [ purpose ] this study measured % isolation and investigated whether it shows a difference 
 between the presence and absence of wrist joint restriction , as well as changes in muscle 
 activity patterns . 
 [ methods ] twenty subjects performed upper extremity functional movement 
 in the manual function test ( mft ) with and without wrist restriction , and the muscle 
 activities of the trapezius , middle deltoid , biceps brachii , triceps brachii , extensor 
 carpi radialis , and flexor carpi radialis were recorded . when there were differences in 
 muscle activation , % isolation 
 was implemented and the changes in the muscle activity 
 patterns were noted . [ results ] in the grasping and pinching tasks , there was a significant 
 increase in % isolation of the upper trapezius and a significant decrease in % isolation of 
 the extensor carpi radialis . 
 carrying a cube task , % isolation of the upper trapezius and 
 middle deltoid significantly increased , whereas % isolation of the triceps brachii and 
 extensor carpi radialis significantly decreased . in the pegboard task , the % isolation 
 values of the extensor carpi radialis and flexor 
 carpi radialis significantly decreased . 
 
 [ conclusion ] the data of this study should be useful for therapists , who can employ the 
 information as material for the education and treatment of patients with wrist joint 
 restriction . 
 therapists may thus look for ways to improve the quality of mobility by 
 predicting the complement mobility depending on the activity performed and then determine 
 whether to facilitate or restrict mobility . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION