[Purpose] This study was to compare the shoulder and trunk muscle activity according to the various resistance condition during knee push-up-plus. [Subjects and Methods] Twenty healthy adults participated in this study (9 males and 11 females). The subjects performed dominant-leg-extended knee push-up-plus apply to resistance in the direction of abduction, adduction, extension and the flexion. The surface Electromyography activities of the upper trapezius, serratus anterior, homolateral external oblique and the heterolateral internal oblique were measured. The Electromyography activities of each muscle were compared using a one-way repeated analysis of variance. [Results] The Electromyography activities of serratus anterior and external oblique muscles between the resistance directions were significantly increased extension. The Electromyography activities of heterolateral internal oblique muscle between the resistance directions were significantly increased adduction. [Conclusion] To suggest use of the decision exercise tolerance orientation when muscle strengthening exercises for shoulder and trunk according to variation resistance in lower extremity during Push-up-plus.

The aim of this study was to investigate the influence of hip abduction velocity and position change on the relative onset times of the gluteus medius, the tensor fascia latae, and the quadratus lumborum in healthy subjects. METHODS: For this study, 15 healthy young adults were recruited. The subjects were asked to move their hip joints up to 35 degrees of abduction at a speed of 70⁰/sec and 17.5⁰/sec in the supine and side-lying positions. Electromyography data was collected for the gluteus medius, tensor fascia latae, and quadratus lumborum to determine the onset times. RESULTS: There were significant differences between the fast speed (70⁰/sec) and the slow speed (17.5⁰/sec) in hip abduction in a supine position and in a side-lying position, relatively. The onset time of the gluteus medius was faster than that of the tensor fascia latae and the quadratus lumborum in the side-lying position at the speed of 70⁰/sec and 17.5⁰/sec.