The Comparison of Muscle Activation on Low-Reaching and High-Reaching in Patient with Stroke

Abstract

[Purpose] The purpose of this study was to investigate the degree of muscle activation of the upper limb muscles during reaching movements in patients recovering from stroke. [Subjects] Nineteen hemiplegic patients participated in low-reaching and high-reaching tasks. [Methods] Changes in muscle activation resulting from performing low-reaching (reaching toward an object at the height of the knee) and high-reaching (reaching toward an object at the height of the shoulder) were measured using surface EMG. The surface electrodes were attached to the trapezius upper fibers, the deltoid anterior fibers, the deltoid middle fibers, the biceps, the triceps, the extensor carpi radialis and the flexor carpi radialis of both the paretic upper limb and the non-paretic upper limb. The independent t-test was used to compare muscle activation. [Results] Based on the results of measurements of muscle activation of the paretic upper limb, the muscle activation of the trapezius upper fibers and that of the deltoid anterior/middle fibers showed significant increases in high-reaching compared to low-reaching. However, for the non-paretic upper limb, significant increases were shown only in the trapezius upper fibers. These results indicate that, there is no difference between the muscle activation of the paretic side and that of the non-paretic side in high reaching while in low-reaching, the muscle activation values of the deltoid anterior fibers and the triceps of the non-paretic side are larger than those of the paretic side. [Conclusion] Muscle activation in reaching movements differs depending on the height of the target and we consider that these differences should be considered when therapeutic interventions are prescribed.