Stability Ball Sitting versus Chair Sitting During Sub-maximal Arm Ergometry

It was predicted that sitting on a stability ball during arm ergometry would elevate cardiovascular parameters when compared to sitting on a chair and that this would be associated with greater recruitment of trunk and leg skeletal muscles. Methods: Open-circuit spirometry, videotaping, blood pressure, heart rate, and EMG were conducted during rest and four minute stages of 15 W, 30 W, and 45 W using a Monark arm ergometer. Twenty-six apparently healthy adults exercised twice, once sitting on a stability ball and the other sitting on a chair (order randomized), with 45 to 60 minutes of rest between. ANOVA for repeated measures and paired-t testing were used for analysis. Results: Oxygen consumption was significantly 10 to 16% higher during exercise while sitting on the stability ball. There were no significant differences between sitting modes for heart rate, SBP, and DBP. Also, resting and exercise rectus femoris and 45 W external oblique EMGs were significantly higher on the stability ball. Finally, the knee was significantly more extended with the feet farther apart and more forward on the stability ball. Conclusion: The stability ball significantly elevates oxygen consumption during sub-maximal arm cranking without significantly increasing heart rate or blood pressure and this is associated with increased thigh muscle activation and lower leg repositioning.