The effects of scapular taping on electromyographic muscle activity and proprioception feedback in healthy shoulders.

We investigated the effects of scapular tape on the electromyographic (EMG) activity of the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), anterior deltoid (AD), and shoulder proprioception in 12 healthy shoulders. Participants were blindfolded and required to complete a target end/mid range position with the hand. They performed six trials under two experimental conditions; no tape and therapeutic tape. EMG activity was measured by surface electrodes, and proprioception was measured by the FASTRAK electromagnetic motion tracking system. Two-way repeated measures ANOVA showed that UT and AD activities decreased 2.65% (p = 0.001), and SA muscular activities increased 1.9% (p = 0.015) in the taping condition. The proprioceptive feedback magnitude was significantly lower in the taping condition than in the no taping condition (11.9°, p < 0.005). Additionally, correlation coefficients were higher than 0.5 between muscle activity and proprioceptive feedback with the taping condition; UT and magnitude in the mid range task (R = 0.516); LT and magnitude in the end range task (R = -0.524); and SA and magnitude in the mid range task (R = -0.576). The results suggest that scapular tape affects the muscle activity of UT, AD, and SA, and that the effects are related to proprioception feedback. These results implicate that the mechanisms by which scapular taping induces effects can be explained by neuromuscular control and proprioceptive feedback factors.

Relationships between posterior shoulder muscle stiffness and rotation in patients with stiff shoulder.

OBJECTIVE: The aim of this study was to investigate differences in muscle stiffness between subjects with stiff shoulders and controls, and to determine the correlation between posterior shoulder muscle stiffness and range of motion of rotation. DESIGN: Prospective, cross-sectional study. SUBJECTS: Twenty subjects with stiff shoulder and 20 healthy subjects. METHODS: Range of motion of rotation, and stiffness in 4 muscles (posterior deltoid, infraspinatus, teres minor and teres major), were measured in affected shoulders and control shoulders using a goniometer and a Myotonometer, respectively. RESULTS: Patients with stiff shoulder had greater muscle stiffness than controls. Except for the teres major, significant correlations were found between internal rotation and stiffness of 3 muscles (r = 0.57-0.72). Among these 3 muscles, posterior deltoid muscle stiffness accounted for 51% of the variance in shoulder internal rotation beyond stiffness from the infraspinatus and teres minor muscles. CONCLUSION: These findings support that muscle stiffness is related to shoulder range of motion. It is important to consider the posterior deltoid, infraspinatus, and teres minor muscles in the rehabilitation of patients with restricted internal rotation of the shoulder.