Bosu ball, unbalanced surface training

I wanted to write about something that has been bothering me for a couple of weeks now, it’s kind of my little rant!

I see trainers around town doing squats, lunges, curls, and anything else you can manage while teetering hazardously on a stability (or Swiss) ball, balance disc, Bosu ball or wobble board. So why do they think this is a fabulous idea, the main being that such exercises add a balance component and not only engage the target muscles, but also engage lots and lots of small stabilizing muscles. Meaning, you get the extra benefit of improved proprioception (awareness of your body in space), so why not?

Yes the Bosu balls and balance discs do work for those of us who've suffered ankle sprains!

The most common type is a lateral/inversion sprain (shown below), in which your foot twists to the inside, stretching or tearing the ligaments on your outer shin. The telltale signs of an inversion sprain are pain, swelling, and eventually discoloration on the outside of the ankle.

Your peroneals, muscles on the outside of your shin, are in charge of preventing inversion. If they're working properly, they'll contract fast enough and powerfully enough to straighten the foot before the ankle rolls and your ligaments stretch or tear.

Once you've suffered an ankle sprain, you're going to have functional ankle instability unless you follow a good rehabilitation program. In this area, the research has shown over and over again that training on unstable surfaces, wobble boards, Bosu balls, balance discs can correct this proprioceptive delay and get rid of functional ankle instability. That's why unstable surface training is a great rehabilitation tool.

Yes, unstable surface training works for people in the rehab setting, BUT 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 right?

The problem is the latest research shows that while doing such exercises are great for rehabbing ankle injuries, they can actually de-power healthy athletes. Now if you're healthy, and your goals have anything at all to do with getting stronger, faster and more powerful, you actually don't want to wobble. (That's not to say you should cut out abs and upper-body exercises like pushups on the ball -- I'm just talking about exercises that involve standing or kneeling on unstable surfaces (especially on the “Buso ball” with the dome facing up)

While researching the subject I came across a study that showed replacing 2 to 3 percent of overall training volume with unstable surface training didn't improve performance, and even more important: unstable surface training minimized improvements in jumping, sprinting, and agility tests. Put another way, the subjects who weren't doing unstable surface training made bigger gains in power, speed, and agility (1). The study explains that one existing criticism of unstable surface training is that such training does not allow for sufficient loading to induce strength gains; the results of this study not only verify that assertion but also demonstrate that unstable surface training actually reduces power (and presumably strength) gains derived from concurrent stable surface training. As such, trainers/coaches applying unstable surface training with a proprioceptive training effect in mind may in fact be impairing the development of important athletic qualities; this finding demonstrates that proprioception is likely best trained in a specific sense with stable surface initiatives.

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.

I would like to note that the study did point out that there may be certain sports (e.g., surfing, snowboarding) for which unstable surface training may offer appreciable carryover to performance, the results of the present study suggest that for most athletes, instability should be applied to training in more sport-specific contexts. These contexts include the application of destabilizing torques applied further up the kinetic chain, just as athletes would encounter in sporting environments where they move on fixed contact surfaces (1).



VH Sports Performance Las Vegas, NV



Information on this article was taken from a study that was done by Eric Cressey for the NSCA Journal of Strength and Conditioning Research. Eric is full of great info; he is known for his work with baseball players and really is a go-to guy for all types of quality information.


1. ERIC M. CRESSEY, CHRIS A. WEST, DAVID P. TIBERIO, WILLIAM J. KRAEMER, AND CARL M. MARESH. THE EFFECTS OF TEN WEEKS OF LOWER-BODY UNSTABLE SURFACE TRAINING ON MARKERS OF ATHLETIC PERFORMANCE. Journal of Strength and Conditioning Research, 2007, 21(2), 561–567



2. CRAIG A. GOODMAn, ALAN J. PEARCE, CALEB J. NICHOLES, BRAD M. GATT, AND IAN H. FAIRWEATHER. NO DIFFERENCE IN 1RM STRENGTH AND MUSCLE ACTIVATION DURING THE BARBELL CHEST PRESS ON A STABLE AND UNSTABLE SURFACE. The Journal of Strength & Conditioning Research. 22(1):88-94, January 2008