Instability training, or exercising while on unstable surfaces, has become both popular and controversial. Performing resistance training on unstable surfaces such as exercise balls, balance boards, stability disks, and foam pads has been shown to reduce force output, but increase activation of “core” muscles of the trunk (Behm and Anderson 2006). No studies, however, have directly compared training outcomes on stable and unstable surfaces.

In a paper published in the Journal of Strength and Conditioning Research, researchers performed a 7 week study of resistance training exercises in 2 groups: one using unstable surfaces and the other on stable surfaces. The researchers hypothesized that the instability resistance training group would demonstrate significantly greater gains in functional testing after the program.

Forty, college-aged, healthy untrained subjects volunteered for the study. Subjects performed squats and vertical jumps, as well as 3 machine-resisted upper body exercises:  lat pull down, butterfly, and bench press. Both groups performed upper body exercises at 70% of 1RM. The stable surface training group performed squats at 75% 1RM, and the instability group performed squats at 50% 1RM while balancing on wobble boards, stability discs, or a BOSU ball. The instability group also performed 4 trunk stabilization exercises on an exercise ball. Subjects More >