Activation and ratio of the upper trapezius and serratus anterior muscles during dynamic and isometric exercises on various support surfaces

Abstract

[Purpose] This study compared the activations of the upper trapezius (UT) and serratus anterior (SA) muscles and the SA/UT activation ratio during dynamic and isometric exercises on various support surfaces. [Subjects] We recruited 12 male subjects, all right-side dominant and with no congenital deformities in the upper extremities and no orthopedic or neurological disorders. [Methods] Push-ups and push-ups plus position maintenance exercises were performed on three different base surfaces: A wobble board, dual wobble boards, and a one-sided wobble board. Electromyography activities of the SA and UT muscles were recorded. [Results] The SA/UT ratio was significantly higher when dynamic exercises were performed using the one-sided wobble board than when they were performed on a normal wobble board or with dual wobble boards. The SA/UT ratio was significantly higher when isometric exercises were performed using a wobble board than when they were performed with a one-sided wobble board. [Conclusion] For clinical applications with a goal of selected SA muscle strengthening, greater benefit is achieved with isometric exercises performed on an unstable support surface and dynamic exercises performed on a stable support surface, as measured by the SA/UT ratio.