The stability ball has gained popularity in the recreational and gym markets for a number of years now. According to a study from the departnemt of kinesiology at Occidental College in Los Angeles, it isn’t just a gimmick.
Researchers compared abdominal muscle activity in subjects perfoming crunches on a stability ball versus a traditional crunch. Forty-one healthy adults participated in the study. The subjects performed the crunch with the ball in two positions; one with the ball at the level of the inferior angles of the scapula (SB-high) and one with the ball at the level of the lower lumbar region of the back (SB-low). Surface electromyography was recorded and analyzed using repeated measures analyses of variance and pair-wise comparisons. Muscle activity for the upper and lower portions of the rectus abdominis and external oblique for a traditional crunch was significantly lower than for the crunch performed in the SB-low position but significantly greater than the SB-high position. Ab muscle activity doubled when the ball was moved from the upper to the lower back position.
What does this mean? The stability ball is not only effective for training the abdominal musculature, but with the correct placement, can increase muscle activity when compared with a traditional crunch.
Source: Journal of Strength and Conditioning Res, 2007, 21(2), 506-509, 2007