The more I learn, the more I’ve realized how inappropriate generalizable research is in many situations. Fortunately, this is starting to change but it is slow going which makes knowing what to do challenging. I came across an article that studied the muscle activation of highly resistance trained athletes on different instability devices such as wobble boards, swiss balls (aka exercise balls), Dyna Discs (think of a small, round, cushion), and BOSU balls (half a Swiss ball on one side and a flat platform on the other). This was interesting to me because I have thought for a long time that experience affects how much these devices work. I messed my knee up as a teenager; I went to physio and they put me on a wobble board. At first they told me to stand on two legs, then immediately progressed me to one leg, then to one leg while I drew various shapes with my non standing leg. I progressed through these challenges significantly faster than typical but I was a figure skater. I stood on one leg and did complex movements regularly, all while balancing on a skate blade. Even today, I am writing this while standing on a wobble board at my standing desk without any issue.
There is significant research into how balance devices support youth athletes in preventing injury, how they support injury rehabilitation, and how they support balance maintenance in seniors (fall prevention). But do all the different balance devices do the same thing? Are they equally effective? I think that anyone could look at a Swiss ball and come to conclusion that standing on it will be harder than standing on any of the other options, but is it the only one that is different? And do all people, regardless of background, find all devices equally difficult?
If you have ever tried standing on the different balance devices you have likely noticed that they are not all equally difficult. It seems to make sense that individuals who are used to controlling for stability, say for example, individuals who train with free weights that your body needs to stabilize compared to weight machines, should have an easier time with balancing exercises, and this is exactly what Wahl and Behm (2008) found.
The researchers looked at what muscles were activated or more activated under three different groups of conditions.
- When it came to standing and squatting on different balance devices only the balance board and the swiss ball increased muscle activation. The swiss ball was a little better than the wobble board. The other two did not create a significant change in muscle activation.
- Doing a series of exercises on flat ground compared to on a Dyna Disc resulted in no significant difference in muscle activation.
- Doing a wall sit until fatigue while standing on the flat side of the BOSU ball compared to flat ground actually resulted in less activation of the soleus muscle (in your calf). However, the authors speculate that other muscles that were not being tested increased in activation in order to achieve the stability on the unstable surface. They base this on the result that individuals got tired faster while doing the wall sit while standing on the BOSU ball.
So what does this mean?
To me, it means that one size doesn’t fit all for training plans, but that isn’t news. You have to consider what a person’s (whether it is you or someone else) background and experience is. Do they engage in stability exercises regularly? And, based on this research, stability exercises don’t necessarily need to be formal stability exercises but resistance training with free weights also creates a lot of stability benefits.
I do have a few questions about the research though. Why did they restrict the exercises to just flat ground compared to Dyna Disk? What would happen if they did track the activation of other muscles through each condition and especially the fatigue condition? Would these results would be maintained even after an individual stopped resistance training? Are the results affected by the age a person starts doing resistance training?