Some of the trends in fitness when the term “functional training” first became popularized were pretty silly. We’ve all imagined, and some of us have even seen, full blown back squats while perched precariously on top of a stability ball. Seriously people, get your head examined.



Bear in mind there are some good reasons to do unstable surface training that are less extreme than the example above. It has been theorized that working on an unstable surface may decrease the load needed to activate the muscles and so it might be good for rehabilitation. Similarly, it is believed that this type of training may work some of your muscles more than stable surface training. However, a study this month in the Journal of Strength and Conditioning challenges that hypothesis.


Breaking Muscle Shop

In case you’re not familiar with the terms, unstable surface training is exactly what it sounds like. It’s when you perform resistance or bodyweight training with all or part of you acting against a surface that itself can move. Stable surface training, on the other hand, is when you are simply standing on the ground, sitting on a regular bench, and so forth.


reebok core board, unstable surface training, squat on bosuIn the study, the researchers compared a standard back squat on the ground to the same movement on a Reebok Core Board, examining the level of muscular activity for each. And no, for once these researchers were not paid to find a benefit.


Interestingly, the Core Board is one of the more stable of available unstable surfaces. This seems like a good thing to me, as unstable surface training tends to reduce the load lifted substantially, and while it might activate your muscles better pound-for-pound, you just plain can’t lift as much. When you’re trying to develop strength that’s a pretty damning effect on your progress. Indeed, in this study participants lifted up to 60% of their stable surface squat maximum.


For the first result of the study - drum roll, please - the researchers determined that the more weight that was lifted, the greater the activity of the muscles. This was true irrespective of the surface. They then discovered that the surface itself did not alter muscle activation. That’s right, the unstable surface did not perform better than the stable one. And presumably the maximum lift for the stable surface was higher, but hard to say because they researchers didn’t test this. If you’re wondering why they didn’t test if the maximum the subjects could lift was comparable on the unstable surface, the reason is probably because it’s not safe to do so. To me, that alone should tell you something.


Since training load was the substantial factor in muscle activation, the researchers suggested ditching unstable surface training, although acknowledging they didn’t test the deeper musculature, which may have had a different result. To this end, researchers noted rightly that few sports are performed on an unstable surface so it’s probably a bad idea to waste your time with it.



1. Yongming Li, et. al., “Similar Electromyographic Activities of Lower Limbs Between Squatting on a Reebok Core Board and Ground,” Journal of Strength & Conditioning Research, 27(5), 2013

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