The Effect of Hand Position Changes on Electromyographic Activity of Shoulder Stabilizers during Push-up Plus Exercise on Stable and Unstable Surfaces

Abstract

[Purpose] The purpose of this study was to determine the effect of hand position changes on electromyographic activity of shoulder stabilizers during push-up plus exercise (PUPE) performed on both stable and unstable surfaces. [Subjects] This study was performed on a cohort of 20 normal adults divided into an unstable surface group (USG) (n=10) and a stable surface group (SSG) (n=10). [Methods] A sling device was used to provide an unstable surface, and a push-up bar was used to provide a stable surface. PUPEs were performed with hands in various positions: the neutral position (NP), the internal rotation position (IRP), or the external rotation position (ERP). Electromyography was used to determine and analyze the electromyographic activity of the upper trapezius muscle (UT), the lower trapezius muscle (LT), the serratus anterior muscle (SA), and the pectoralis major muscle (PM). [Results] Comparison of the results within the USG and SSG showed significant differences depending on the hand position used during the exercise. Comparison between the USG and SSG showed that the ERP hand posture resulted in significant differences in electromyographic activity of the SA in the USG. [Conclusion] The electromyographic activity of the SA indicated that performing PUPEs using the ERP on an unstable surface provided more effective intervention for shoulder stabilization than ERP on a stable surface.

Serratus Anterior and Upper Trapezius Electromyographic Analysis of the Push-Up Plus Exercise: A Systematic Review and Meta-Analysis

“…Twelve articles focused on the effects of the base of support during PUP exercises. 9,[15][16][17][18][19][20][21][22][23]51,52 After further checking for the meta-analysis, 1 article was excluded due to insufficient data for the means and standard deviations. 51 Therefore, 11 articles were included in this meta-analysis for analyzing the differences in SA and UT muscle activity during the PUP performed on stable and unstable surfaces.…”

“…[12][13][14] After finding that the standard PUP (SPP) and knee PUP exercises induced the highest SA and lowest UT : SA EMG measures, Ludewig et al 8 recommended these exercises for selective SA strengthening. Researchers 5,9,[15][16][17][18][19][20][21][22][23][24][25][26] have investigated whether the PUP exercise performed on different unstable bases stimulated mechanoreceptors and increased SA EMG activity, thereby enhancing shoulder-joint stabilization. The use of unstable or stable surfaces during the PUP exercise is under debate.…”

“…The functional length of the SA can change the contraction distance of the muscle, which affects muscle activity. Researchers 16,[31][32][33][34] have examined muscle activity using different hand orientations and at shoulder-flexion angles of 1108, 908, and 708 during the PUP exercise. Lee et al 16 reported larger SA EMG activity during the PUP exercise with the shoulder externally rotated than with it in neutral or internally rotated.…”

“…Researchers 16,[31][32][33][34] have examined muscle activity using different hand orientations and at shoulder-flexion angles of 1108, 908, and 708 during the PUP exercise. Lee et al 16 reported larger SA EMG activity during the PUP exercise with the shoulder externally rotated than with it in neutral or internally rotated. Kim et al 17 found that SA activity during the PUP exercise was higher when the ipsilateral lower extremity was raised than when the base of support (stable or unstable surface) was changed.…”

Comparison of the Upper and Lower Trapezius and Serratus Anterior during Push-up Plus Exercise with and without an Elastic Shoulder Band

“…However, there are different opinions regarding whether the push-up plus exercise should be conducted on stable or unstable support. Lee et al (2013) reported that performing the exercise on unstable support was more effective at increasing muscle activity and stimulating shoulder joint proprioceptors.…”