If you take a trip into any fitness center or rehab facility, you’ll likely see all types of different equipment used to build physical fitness or rehabilitate an injury. One specific type of equipment that has seen big growth in both types of facilities over the past decade has been unstable surface training equipment. Examples of this equipment include foam pads or inflated rubber discs to stand on, physioballs (also called swiss balls), and more. While foam pads and rubber balls are fairly inexpensive and low tech, unstable surface training has gotten more technologically advanced with even expensive machines with vibrating platforms designed to create an unstable surface for training.
Unstable surface training can be used in all types of exercises. For example, while standing on a foam pad on the ground, you could perform squats or hold your balance on one leg. Or you could place your hands on a physioball and perform push-ups instead of on the ground. Most any exercise can incorporate some type of unstable surface training.
Proponents of unstable surface training promote that it increases the stress on your muscles, thereby increasing strength and balance. I’ve heard people say regarding unstable surface training, “It works all of the small, stabilizing muscles that don’t get worked with other movements.” Though interestingly, I’ve never heard someone actually name any of these supposed “small muscles” that are worked only with unstable surface training. However, is this true? Does unstable surface training make you stronger than training without these implements? Does it improve balance versus performing traditional strength training exercises?
Well, to answer that question, we’ll ask what we always ask, what does the science say?
Published in 2015 in the Canadian Journal of Sports Medicine, a systematic review (a study that pools the results of multiple studies) examined studies related to the impact of unstable surface training on strength, power, endurance, and balance compared to no training or compared to stable surface training (i.e. traditional training on the ground, floor, or hard surface).
While many studies often isolate one specific age group, one interesting goal of this study was to examine the impacts of unstable surface training across the lifespan. The authors looked for studies on kids, adolescents, young adults, and seniors, coming up with a handful of studies that were rigorous enough to be included in the review. Of note, to remain consistent on the population they were studying, the authors only included studies on healthy individuals, meaning no studies involving rehabilitation of injured subjects were included.
So what were the results?
Well, as you might expect, unstable surface training was better than no training at all in improving muscle strength, power and balance across the lifespan. Compared to training on stable surfaces, though, the advantage was not so large. Small effects were found when comparing unstable surface training versus more traditional training in adolescents and young adults, however, when you compared these different training methods over just one metric, such as maximal strength or balance, the advantage disappeared.
So why might unstable surface training not have a readily apparent advantage over stable surface training in adolescents and young adults? Well, let’s consider the performance of a few free-weight exercises: the squat, the overhead press, and the biceps curl. All of these (and many other) movements create instability that your body has to control due to the placement of a bar, dumbbells, or other types of resistance either on the shoulders (as with squats), above the body (as with the overhead press), or in front of the body (as with bicep curls). The outside forces created by using resistance with these exercises disrupts the center of gravity and challenges the body to maintain balance. The use of unstable surfaces challenges the body’s stability and equilibrium more than stable surfaces, however, this additional stress may not be enough to cause the body to adapt in some greater way.
So how about performing stable versus unstable surface training in older adults? Which is best? Unfortunately, the authors did not identify any studies that were rigorous enough to compare unstable versus stable surface training in older adults. However, as mentioned earlier, unstable surface training performed better when compared to no training at all and specifically for older adults, unstable surface training improved balance to a large degree versus no training. However, there was only a range from no-effect to a moderate-effect of unstable surface training on strength, strength endurance, and muscle power. So, if you are an older adult, does this mean you should absolutely train with unstable surface equipment due to the large impact on balance compared to no training? Or, due to the results from adolescents and young adults, should you not worry about incorporating unstable surface training in your routine if you’re already performing traditional training?
Check back next week as I round out some further analysis from this study on the topic as well as give my own opinion after using unstable surface training myself and with patients.
Nick McClary earned his doctor of physical therapy from the University of Tennessee. He also holds a masters in business administration. He is a native of Georgetown County, lives in Pawleys Island, and works in Georgetown. Send him your health and fitness questions at: email@example.com.