Tip 174: Unstable surfaces do not increase activation more than stable surfaces. Contrary to what the “functional training clowns” would like you to believe, performing dumbbell chest presses or shoulder presses on Swiss Balls do not increase activation of the rectus abdomini, deltoids or pectoralis major muscles. (JSCR 24: 1028-1033,2010).Other studies, using more experienced lifters showed greater activation on more stable surfaces.