I just wrote a rather lengthy article and research review on the use of Swiss Balls and so-called “stability training” (a training curriculum which creates instability to train the body for stability). After reviewing a great deal of the recent research, the general finding for stability training is that it’s little more than a fad exercise craze with little scientific efficacy behind it.
About the only benefit to be found from such hokey exercise tools as Swiss Balls, Dyna Discs, tilt boards, Bosu Balls, etc. is that they train the abdominals a bit more than stable platform training (though even this isn’t engraved in stone as such muscular efficiency is greatly dependent upon the abdominal exercise and the form involved).
There is also a great deal of irony in this finding because these devices are intended to train the core musculature of the trunk as a whole, not just the abdominals. However, much of the research finds that the muscles of the lower back aren’t typically targeted any more than they are on stable platforms with more traditional exercises. This makes stability training a rather pointless endeavor since traditional exercises have been conclusively shown to train all supporting structures – including the trunk musculature – along with the main target muscles of the exercise in question.
For more information, see my article Swiss Balls & Stability Training: Effective Workout or Pointless Fad? and my breakdown of the research findings here Swiss Balls and Stability Training Research.