EMG analysis of upper and lower rectus abdominis during exercises performed on and off a swiss ball

Swiss ball are becoming widely used for training both in athletic programs and rehabilitation. It plays important roles in trunk movements and spine stability besides prevention of low back pain. As it consequence, the purposes of this research is to investigate the muscle activity of the upper and lower rectus abdominis (URA and LRA) as its target muscles during four selected various type of exercises on and off the usage of Swiss ball. The selected abdominal exercises are curl up on flat surface, Swiss ball curl up, leg raise on flat surface and Swiss Ball leg raise. Fourteen healthy subjects are requiring performing the exercises following maximal voluntary isometric contraction and the presence of flexion relaxation.In summarization, the muscle of upper rectus abdominis were most activated when doing Swiss Ball curl up similarly with the lower rectus abdominis as a target muscles. Meanwhile for the flexion relaxation phenomenon were rapidly occur when doing in the unstable surface by referring to its flexion relaxation ratio. Besides, the gender differences also appear the significance difference in muscle activation where most of the exercises were affected more on the male contrary with flexion relaxation which affected more on female due to the differences condition of muscle strength.