The one thing that the above have in common is that they all irritate the hell out of me. Well, clowns actually scare me a little but that’s another article.
The marketing behind “unstable surface training” has been effective at making people think there’s an easier, more effective way to train. And, people like doing things that are different - I get that. I like being creative in my programming too. But when I see young athletes (or adults) doing squats, deadlifts, curls or other circus acts on a BOSU ball or wobble board I want to 1. Laugh, 2. Ask their trainer where the jugglers and unicyclists are.
To be fair, there are some instances where their use is warranted. In his manual, The Truth About Unstable Surface Training, Eric Cressey noted that for athletes with ankle injuries the Bosu could help provide a rehab stimulus. Outside of that, the research on this topic points to virtually no benefits beyond entertainment value. In fact, studies have shown incorporating as little as 5% of your training volume on unstable surface training will make you weaker.
For starters, unstable surface training promotes abnormal motor patterns. Watch someone squat on one and you’ll see their knees cave in, feet pronate (turn in on the arch side) and hips internally rotate...it’s an ACL injury waiting to happen. A high percentage of us have trouble performing a perfect squat or deadlift on a stable surface - we don’t need any more instability!
Secondly, unstable surface training inhibits maximum force production. You can’t use near the same weight on a BOSU compared to a stable surface. A recent study in the Journal of Strength and Conditioning Research tells us that stable surfaces result in more muscle fiber activation and greater force production than unstable surfaces when performing lifts with equal loads.
The study compared the effects of a five-week periodized strength training program on vertical jump height and 30-meter sprint speed in Division 2 collegiate female soccer players. Participants trained three sessions a week and performed four lifts each session. They were divided into two groups (stable and unstable), and both groups performed the same lifts but the unstable group completed two of the exercises each session on a Bosu ball. The exercises performed on the Bosu included back squat, Romanian deadlift, bent over row, push press, and forward lunge. Equal loads were used for the stable and unstable training.
Both groups improved 30-meter sprint times after the training period, but the stable group got faster than the unstable group. This finding is supported by previous studies that show that stable training improves short sprint speed more than unstable training. Additionally, the stable group significantly improved vertical jump height and the unstable group had no improvements.
Unstable surfaces inhibit maximal force generation, in part because the muscles you are trying to train (agonists), end up firing less. The muscles on the opposite side of the joint (antagonists) fire more in an effort to stabilize the joint in that unstable position.
Finally, another popular claim made by proponents of unstable surface training is an increase in “core stabilization”. As with balance, any core stabilization that is possibly enhanced by activity on an unstable surface has NOT been shown to transfer to stable surfaces. Improving your balance on a Bosu Ball will only make you better at ....balancing on a Bosu Ball! Most research even shows that performing resistance training exercises on stable surfaces requires MORE core activation and stabilization than performing the SAME exercise on an unstable surface. When performing an exercise on an unstable surface, the weight has to be reduced to such an extent that less overall activation of core musculature occurs. Instead of doing your squat press with 95 pounds, you would have to do it with 50 pounds while standing on a BOSU ball.
The takeaway: if you want to get stronger and faster (and who doesn’t?), STABLE surface training is where it’s at. On flat ground you’ll lift more weight, generate more force (speed), and have greater core activation than you would on unstable ground. But if you want to learn some cool circus tricks...ok, you get the point.