Let me say that I'm honored to be quoted in the same piece as guys such as Dave Tate and Eric Cressey, as I've been reading their material for years. And I particularly liked Eric Cressey's contribution regarding "functional" training with bosu/stability balls:
Myth: Unstable-surface training works for everybody.
Mythbuster: Eric Cressey
While UST works for people in the rehab setting, a lot of trainers assume they can apply the same techniques to healthy athletes and prevent ankle sprains, improve balance, and enhance performance.
This makes perfect sense. We talk about "prehab" all the time when it comes to back and shoulder joints, so why wouldn't preemptive ankle training help you avoid sprains?
But then I dug into the research for my master's thesis, and what I found there surprised me: There's no evidence that UST reduces injury risk or improves performance in healthy, trained athletes.
When I conducted a study of my own, I had the good fortune to use one of the country's best Division I men's soccer teams as my subjects. Our results were published in the Journal of Strength and Conditioning Research in August 2007.
My study showed that replacing 2 to 3 percent of overall training volume with UST didn't improve performance. But I also discovered something even more important: UST minimized improvements in jumping, sprinting, and agility tests. Put another way, the subjects who weren't doing UST made bigger gains in power, speed, and agility.
So just because something works in rehab doesn't mean it's useful for healthy athletes. In fact, if it takes the place of something else in their training, the opportunity cost seems to make things worse.
Once the study was finished, I invested a lot of time creating a framework for this type of training. One goal was to show the appropriate uses for UST, and there are some. But I also wanted to show an overall progression model for true instability training in healthy athletes.
A lot of people choose the binary route — either "it sucks" or "it's awesome" — but by the time I finished the 100-plus-page report (which you can purchase here), the answer turned out to be a lot more interesting and complex than those two extremes.
The next in the Mythbuster series might have something from me regarding kettlebell (aka dangerballs aka kookballs) training, but I'll give a sneak preview in a subsequent post.