Core stability exercises on and off a Swiss ball

Objectives: To assess lumbopelvic muscle activity during different core stability exercises on and off a Swiss ball. Design: Prospective comparison study. Setting: Research laboratory. Participants: Eight healthy volunteers from a university population. Intervention: Subjects performed 4 exercises on and off a Swiss ball: inclined press-up, upper body roll-out, single-leg hold, and quadruped exercise. Main Outcome Measures: Surface electromyography from selected lumbopelvic muscles, normalized to maximum voluntary isometric contraction, and median frequency analysis of electromyography power spectrum. Visual analog scale for perception of task difficulty. Results: There was a significant increase in the activation of the rectus abdominus with performance of the single-leg hold and at the top of the press-up on the Swiss ball. This led to changes in the relation between the activation levels of the lumbopelvic muscles measured. Conclusions: Although there was evidence to suggest that the Swiss ball provides a training stimulus for the rectus abdominus, the relevance of this change to core stability training requires further research because the focus of stabilization training is on minimizing rectus abdominus activity. Further support has also been provided about the quality of the quadruped exercise for core stability.