If you think that weight training on an unstable surface such as an exercise ball always activates more muscles, think again. According to research out of California State University, Northridge, training with lighter loads on an unstable surface may not give you the benefits you’re hoping for.
As reported in the January 2010 issue of the Journal of Strength and Conditioning Research, 30 resistance-trained subjects performed shoulder presses for three sets of three repetitions, including barbell and dumbbell presses seated on a bench and on an exercise ball. Based on surface electromyography readings for eight muscles — the anterior deltoid, middle deltoid, trapezius, triceps brachii, rectus abdominis, external obliques, and upper and lower erector spinae — the researchers found that as the instability of the exercise increased, activation of most muscle groups decreased. (The upper erector spinae, on the other hand, experienced greater muscle activation when subjects performed barbell presses on the Swiss ball versus the bench.)
Take it to the gym: Don’t get blinded by the functional fitness buzz. Your tried-and-true weightlifting basics make you stronger.