Effect of Wrist Joint Restriction on Forearm and Shoulder Movement during Upper Extremity Functional Activities

[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.