• Bryan Thomas

Training to be Stable or Unstable?

Updated: Apr 10, 2020

Today I wanted to talk to you about a topic that seems to come up quite a bit in the fitness world.  This is something I see used quite a bit and there still seems to be a great deal of confusion about how to use it and I get asked frequently what my thoughts on the matter are.

That's right, I want to discuss unstable surfaces.

In case you aren’t sure what I am talking about when I say unstable surfaces, I’m talking about your fitness training devices like your Bosu balls and you swiss balls and your wobble boards. 

It is a rare event in this day and age where you can walk into a typical fitness center or gym and not see special racks designed specifically to store these giant inflatable balls toa tower to hold all the Bosu balls.

These pieces of equipment are designed to make the person using them less stable.  As a result, everything that you do when you are standing or sitting on these balls will become harder because you have a much less stable base of support. 

This is where things get confusing. 

Typical fitness training mantras preach things like “harder is better”or “You have to fire those stabilizers”or even “Olympic skiers can squat all the way down while standing on these”

While they certainly do make things more difficult to do while standing or sitting on them, the real issue is whether or not that level of difficulty is worth the extra effort relative to the results you are going to get. 

Since we are most concerned with brain function, our first question becomes “what does this do for my brain?”

Well, let’s take a look at some of the research and see what it ACTUALLY says about unstable surface training.

This paper from the Canadian Society for Exercise Physiology states:

"Since the addition of unstable bases to resistance exercises can decrease force, power, velocity, and range of motion, they are not recommended as the primary training mode for athletic conditioning.

When we look at this through a neurological lens, we can see that training on these types of surface may actually compromise our performance in our desired sports. Our brains get good at what we practice.  If we practice making things harder to do well, and in ways that make us weaker, it becomes very difficult to get good at the things that give us the most return on our investment of time and energy.  But what about engaging my “core?” First and foremost, the idea of “core training” is rife with misconceptions and is unfortunately not the focus of this particular post.  I will address this notion in-depth later on, but for now I would recommend the fantastic article by Osteopathic Doctor Eyal Lederman found here.

One of my absolute favorite quotes from that article is: “If a subject is trained to contract their TrA(Transverse Abdominus) or any anterior abdominal muscle while lying on their back, there is no guarantee that this would transfer to control and physical adaptation during standing, running, bending, lifting, sitting etc. Such control would have to be practiced in some of these activities.”

What he is basically saying there is that just because you practice training your “core” musculature in one position does NOT guarantee that you will be good in other positions.  Again, we get good at what we practice.  A beautiful paper from the Journal of Strength and Conditioning found: Unstable chest press force was 59.6% less than stable chest press force” I don’t know about you but if someone told me they wanted me to train to be 60% weaker than I could be, I would be mighty perturbed. Why is it that these responses to instability training make us weaker?

Photo credit When you look at the information that travels through the spinal cord, you only have two tracts that send information for voluntary movement to the muscles from the brain.  These are the Lateral and Anterior Corticospinal tracts. What this means is that you have a substantially bigger amount of weight given to other pathways that control reflexive stability and sensory information travelling to the brain from the body. When looking at how much of the signal that our brains generate to create movement, only 10% of that signal goes to the Corticospinal tracts to contract the muscle voluntarily.  The remaining 90% of that signal goes to the pathways that work to reflexively keep us stable. Try this: Put one arm out in front of you.  What you just did was change your center of gravity. Notice how you didn’t fall over? Now, if you did fall over, you should probably hurry to a doctor because you may have some brain issues going on. Our movement to create that change in our center of gravity would cause us to fall if we didn’t have strong function in our reflexive stability systems.  Put another way, we were able to stabilize without thinking about it.  That’s how stability training should be done.  Find ways that change your center of gravity naturally and your brain should kick in to keep you upright.  If we deliberately train our brains that our environment is unstable, that our primary mover muscles will never work as well as they could or should, then we can actually make ourselves weaker, not better.  The brain doesn’t change how it works because of some gimmicky piece of fitness equipment.  The brain works the best way it knows how to accomplish the goal of keeping you from dying and keeping you upright during movement. We get good at what we practice, and therefore, we may want to practice things we actually want to get good at.  Thanks for making it this far.  I look forward to sharing more with you in the future. If you haven’t yet, please follow me on Facebook and Instagram to make sure you don’t miss out on all the great things we got going on here at Performance Neuro. See ya soon.


References: Behm DG, Anderson KG, Curnew RS. 2002. Muscle force and activation under stable and unstable conditions. J. Strength Cond. Res. 16(3): 416-422 a

Behm DG, Drinkwater EJ, Willardson JM, Cowley PM, Canadian Society for Exercise Physiology. 2010. Canadian Society for Exercise Physiology position stand: The use of instability to train the core in athletic and nonathletic conditioning. Appl Physiol Nutr Metab. Feb;35(1):109-12.

Lederman E. 2007. The Myth Of Core Stability. CPDO Online Journal. June, p1-17.