If you’re up to snuff on your anatomy and physiology, you know that the rectus abdominis is a single muscle. However, you may have found yourself caught up in the debate about whether you can train the upper and lower portion in different ways.
Researchers from Dalhousie University in Halifax, Nova Scotia, were also curious about this topic. They studied the effects on the upper and lower rectus abdominis of the crunch, crunch on a stability ball, crunch with an Ab Trainer, supine leg lowering, stability ball roll out and reverse curl up. Their research was reported in the August 2003 issue of the Journal of Strength and Conditioning Research.The results?
Researchers reported no significant difference between the upper and lower portion of the rectus abdominis during the concentric phases of the exercises. However, while all exercises produced a response in both the upper and lower portions of the muscle, the crunch, crunch with an Ab Trainer, and crunch on stability ball produced higher electromyography (EMG) activity on the average than the supine leg lowering, stability ball roll out and reverse curl up. Also, the crunch on stability ball had a significantly higher EMG activity than all other exercises due to the balance component of the exercise.