Unstable Surface Training is now quite popular. It is now marketed as a way to greatly improving strength as well as stability. Or does it?
During the 90’s, not many gyms would use unstable surface equipment. The swiss balls, and later the BOSU, were still being popularized in the rehabilitation setting and they were used for the rehabilitation of patients who have difficulty in maintaining control of their torso and balance. They were used to improve the functional abilities of Cerebral Palsy, stroke, and similar patients. They were also very useful in treating injured athletes and good Physical Therapists helped in maintaining injured athlete’s fitness levels while they were recovering from injuries. The BOSU, as well as teeter boards, and balance discs were used to re-establish a patient’s balance and control over an injured ankle or knee. Eventually, these rehab equipments found their way into gyms for use by the general population. They are very useful in the fitness industry especially since “core” training was the hype a few years ago- and even until now.
The unstable surface devices are useful from the rehabilitation setting to the general population for their goal- to improve functional abilities like standing balance, walking, gait training to improving local muscular endurance and control of the midsection or “core”. Now, it seems that they are also being marketed for the athletic population as a way to help improve athleticism and performance. The general population whose aim is to improve fitness is different from the elite athletes whose aim is to improve performance. That is when it can be confusing. People want to be glamorous and to be identified with a special group. It is always about the inflated ego. And that is why advertisers are very successful. They target the general population- say those who love to work out in gyms and make them relate to actual athletes by using famous athletes as models for their products. People would think that using a particular product would then make them into good looking athletes. Now, young athletes and sports coaches get confused. They would ask the strength coach to use BOSU, or swiss balls, or TRX for their training to improve their performance. It is the other way around but they may not be totally wrong. If improving their performance means re-training an injured ankle, then they would have a point, or their performance level is not yet that high as in the case of developmental teams. But remember, best performance is the expression of the athlete’s full potential. And what Strength Coaches do to help athletes do this is to help them maximize expression of their strength. That is why there are Strength coaches. And this strength is supported with good conditioning.
Now, going back to Unstable Surface training- will these devices help in the expression of maximum strength? There was a study conducted in 2008 which compared 1RM strength, and upper body and trunk muscle EMG activity during the barbell chest press exercise on a stable (flat bench) and unstable surface (exercise ball). The results show that there was no difference in 1RM strength or muscle EMG activity for the stable and unstable surfaces. In addition, there was no difference in elbow range-of-motion between the two surfaces. Taken together, these results indicate that there is no decrease in strength or any differences in muscle EMG activity for the barbell chest press exercise done on an unstable exercise ball when compared to a stable flat surface. It does not show that performing the bench press on an unstable surface would recruit more motor units nor decrease force output.
Another study was published on 2013. It was done to to compare force output and muscle activity of leg and trunk muscles in isometric squats executed on stable surface (i.e., floor), power board, BOSU ball, and balance board. The findings show that increasing the instability of the surface during maximum effort isometric squats usually maintains the muscle activity of lower-limb and superficial trunk muscles although the force output is reduced. This suggests that unstable surfaces in the squat may be beneficial in rehabilitation and as a part of periodized training programs. This study suggests that unstable surface training is valuable in the rehabilitation of injured athletes since it elicits same muscle activity without the maximum load thus it helps maintain or reduce the decline of fitness levels while waiting for the injury to heal.
As for performance, another study was done to compare the production of force and paraspinal muscle activity between deadlifts carried out in a standard way and with different instability devices (Bosu and T-Bow). Thirty-one subjects performed an isometric test for 5 seconds in each condition. After that, they performed 5 repetitions with 70% of the maximum isometric force obtained in each one of the previously evaluated conditions. Records of electromyographic activity and force production were obtained. The subjects produced more force and muscle activity on the stable surface than under the other conditions. These data shows that the performance of deadlifts under stable conditions favors a higher production of maximum strength and muscle activity. The researchers conclude that the use of instability devices in deadlift training does not increase performance, nor does it provide greater activation of the paraspinal muscles. These results also questions the value of unstable surface training in the performance of other types of exercises.
One sport, (and occupation) that requires exerting near maximal effort repeatedly on an unstable surface is offshore sailing. Sailors on big boats have to drag, pull and hoist very heavy sails. And when they sail upwind on stormy seas, they have to do it on an inclined surface which bounces all around with no rhythm. Fishermen who do not use wind powered boats still have to work on the same unstable surface. And you cannot stop in offshore sailing. When you are tired, you cannot stop the waves nor the wind. You still have to exert effort in order to maneuver your boat until you reach your destination which may take a few weeks to months.

Photo courtesy of Michelle Wong
Do they train on the BOSU, swiss balls and the like? Maybe, but most likely not. Their actual training is sailing itself. Strength training does supplement their training since they need to exert near maximum effort. Squatting or bench pressing on swiss balls for them is like a BMX race athlete training on a bike with those stabilizing trainer wheels.
Unstable surface training has its merits since it lets the body use a lot more motor units. More torso stabilizer muscles are active when doing an exercise on an unstable surface as compared to doing it on a stable surface. But once the initial challenge of learning how to use an unstable surface device has been overcome, the body will use only the required motor units to perform the exercise with the load. Think about it this way, when learning how to ride a bike, you tense up, use a lot more effort and action to control and move the bike without losing balance. But once you learned how to ride a bike, you are more relaxed and use lesser effort. Even if you did not ride a bike for many years, you would still be able to if you wanted to.
To sum it up, Unstable Surface Training has its uses but like anything that is made into a product, advertisers and promoters can always hype it to attract the attention of consumers. If you are an elite strength and power athlete and if your goal is to further maximize your strength and power, you probably have known all along that there is no way squatting on a swiss ball can make you break your PR, it can only break one’s bones and snap ligaments. But if you are a regular fitness guy/gal, these unstable surface devices may have a place in your training- although it will not be the main exercise. It is good to try different exercises once in a while to explore how you can use them for your improvement. For weekend athletes, these devices still can help you improve. Most weekend athletes do social sports like basketball, badminton, even trail running. These sports activities demand good knee and ankle control. It is good to try some exercises on the BOSU for ankle and knee control. But do not go overboard and do barbell squats on the swissball! Some people can do them but ask yourself these questions:“What good does it do for me if I will do it?”; “If I can do it, should I do it just because I can?, will it make me better?”; “Will I gain any benefit from this exercise and are the benefits greater than the risks?.” (click here for warm-up exercises which also improve ankle and knee proprioception) There is a story of a well known and respected Strength and Conditioning Coach and former athlete who was demonstrating squatting on a swiss ball. He does squats on swiss balls very well but unfortunately, on that day he was demonstrating, he landed badly when getting off the swiss ball that he tore some ligaments in his knee. If we think about it, how much more if a lesser skilled athlete, with weaker ligaments, would perform a loaded exercise on the swiss ball? His chances of getting hurt would be so high that it is insane to train for squatting strength on top of a swiss ball. And Strength Coaches would first think about not harming an athlete when prescribing an exercise.
Remember, the person who is ultimately responsible for your health and safety is YOURSELF. You have chosen to read this blog probably because you want to improve the quality of your life. The writer tries his best in his own way to convey information which he knows will be useful in improving strength and overall fitness. Use and share the information. And temper what you do with your good judgement. Train Better, Live Better!