Differences in Scapular Movement and Muscle Activity of the Periscapular Muscle According to the Belt-tying Movement Method / The Japanese Journal of Rehabilitation Medicine

ABSTRACT

Objective：The belt-tying movement is of two types. One uses an abduction method in which the scapular on the same side as the upper limb to be moved is touched. The other type uses an adduction method in which the scapular on the opposite side is touched. The purpose of this study was to determine the scapular movement and muscle activity of the periscapular muscle in each method.Methods：Ten healthy men performed abduction and adduction belt-tying movements. The scapular upward rotation, anterior tilt, and internal rotation angles were measured using a three-dimensional operation analysis device. The joint angles were compared between the abduction and adduction methods by using a multiple comparison procedure. In addition, the muscle activities of the trapezius upper, middle, lower, and serratus anterior muscles were measured and analyzed using surface electromyography.Results：The abduction method involved an anterior tilt and upward rotation of the scapular muscle. By contrast, the adduction method involved an upper limb descent at the L5/T12 level, a scapular anterior tilt and upward rotation, and a scapular downward rotation at a level higher than L5/T12. The muscle activity of the upper trapezius muscle fiber was always increased between the ptosis and T7 by the abduction method but was attenuated at a higher level than T12 by the abduction method.Conclusion：Rehabilitation therapy that focuses on scapular anterior tilt and downward rotation, and the muscle activity of the upper trapezius muscle fiber is important for acquiring the belt-tying movement ability using the adduction method.