Beyond Balance Training
by Anthony Carey, M.A., CSCS, CES
Training on unstable and/or labile surfaces is one of those divisive topics within the fitness and sports conditioning worlds. There seems to be a consensus to the benefits of training on unstable surfaces in the rehabilitation environment, but unfortunately, there is very often those that "do" and those that "don't" in the fitness and sports and conditioning worlds.
Perhaps it's time for everyone to rethink our positions and dogma.
If we take a look at this topic from a research and application perspective, we can see that both camps are right...some of the time. There is ample evidence to support the benefits of using unstable training even with highly trained athletes. And there is also ample anecdotal evidence (much of which has been the catalyst for research) that professional trainers and coaches have been misguided and even dangerous in the use of such equipment. And there is significant evidence to support the benefits of training on stable ground especially for ground-based athletes.
For whom? For what? These are my two favorite questions and what gives clarity to interpreting the literature and how to apply it to the population you are working with. Who are you training? What are their goals? What responses are you trying to elicit during the session(s)? Where are they in their training cycle?
For any coach or trainer to say the training on an unstable surface is "wrong" has not read the research. Much of the opposing views on using labile surfaces are directly related to what your objective is. All too often the discussions are comparing apples to oranges versus apples to apples.
The most obvious application is to use these surfaces is for balance training. Poor balance is a predictor of increased lower extremity injury risk in both athletes and non-athletes (McGuine and Keene, Olsen et. al., Wedderkopp et. al.). The goal of balance training is to create a perturbation of the body's center of gravity (COG) and facilitate the neuromuscular mechanisms that respond and react to bring the COG back within the body's base of support. Balance training can be used for postural and neuromuscular control improvements to affect both static and dynamic balance. And training on labile or unstable surfaces does correlate with balance improvements on stable ground so it is transferable. (Yaggie and Campbell, DiStefano et. al., Astrid et. al.). Therefore, the anecdotal view that you should only train on a wobbly surface if you play on a wobbly surface does not stand up to the existing literature in regards to improving the functional attribute of balance.
Conversely, the research does not support practicing specific sports related technical skills on an unstable surface. For example, having a golfer practicing his drive while standing on two inflatable discs probably has little benefit in improving the skill. And it could be argued that it actually interferes with the motor control efficiency of performing the task because of the variation in afferent information and the departure from the execution of the final, desired movement pattern.
Many studies on stable versus unstable training use elite level college athletes as the subject pool. We expect elite level college athletes to be physically superior in strength, speed and motor control to most non-elite level athletes. And as such, a "ceiling effect" has been described in the literature (Holm et. al., Kovacs et. al.). That is athletes did not show improvements in static balance but did show improvement in dynamic balance due to the fact that the tests for static balance were not challenging enough and there was little if any way to improve.
It seems intuitive that you are not going to be able to produce as much force, velocity and power if you are on an unstable surface. The research supports this in trained lifters and athletes. A trained athlete and experience lifter is not going to be able to overload the muscles enough for ongoing strength adaptations. Although the research does show that strength gains on stable versus unstable surfaces can be matched with untrained individuals (Sparkes and Behm).
Thinking Outside of the Unstable Training "Box"
What if force, power and velocity are not the current training goal? Then there are many applications for unstable training that are beneficial for clients and athletes of all levels.
A common misconception is that the only goal of training on an unstable surface is "stillness". That is to minimize or even eliminate movement of the body while using a labile surface. This should not always be the case. And in fact, certain pieces of equipment discourage "stillness" in exchange for reaction.
Let's consider the Core-Tex™. The flat platform on top moves on a series of 3 ball transfers creating a simultaneous tilt, translation and rotation=movement along 3 axis. Unlike other unstable surfaces, the objective is to move and react versus "stillness". We refer to this as an ongoing "pitch and catch" between the user and the Core-Tex™. As such, each and every movement of the Core-Tex™ creates a unique reaction within the kinetic chain.
For example, when doing a push-up with rotation on the Core-Tex™, the timing and location of the tilt, translation and rotation will be different on each repetition. This is because the slightest difference in downward pressure on the platform from either hand will change the motion. Therefore, each repetition literally produces a different joint angle and different recruitment from the motor unit pool.
This variety in muscular recruitment would not be limited to just the chest, shoulders and arms. It would also create the same unpredictable demands on the core musculature.
The Core-Tex™ is unique in that the rotation is unrestricted in 360 degrees. This unique feature allows the user to recruit the oblique myofascial lines connecting one side of the torso and the opposite lower extremity that are the foundations of functional movements (walking, running, throwing, lunging, etc.).
This kind of variety in muscle recruitment is very difficult if at all possible to produce with familiar ground-based movements. Using the Core-Tex™, the body senses the unpredictability of the surface and increases muscular contractions for stabilization. Although this may not allow for maximal force production, it does increase over muscular activity and metabolic cost.
If the user is standing on the Core-Tex™ (with or without the handrail) and performing an upper body exercise, the same scenario occurs. Each and every repetition will change the joint angle and the muscular recruitment. For example, doing a bicep curl while standing will create a weight shift and therefore motion of the Core-Tex™ platform. As the base tilts, translates and rotates, the lower extremities react, create motion at the hips and pelvis, the thoracic spine laterally flexes and rotates and the shoulder girdle position has changed-effecting each and every repetition differently. The loads lifted will not be as much as on solid ground, but the muscular recruitment will be much more varied.
The vast majority of fitness professionals are not working with highly trained athletes. And when working with athletes, a science based periodization program would still call for sub-maximal work loads during the training cycle. Therefore, during a strength/power phase it would not be advisable for the athlete looking to build peak strength to perform exercises on an unstable surface. Yet an untrained client who does want to build strength may achieve that goal by training on an unstable surface at lower loads and with less torque to control at the joints.
If you are a personal trainer, strength coach, athletic trainer or physical therapist, then you are also an environmentalist. Webster defines environmentalist as "one concerned about environmental quality especially of the human environment".
In this context we are not talking about air, water or trees. We are talking about the environment that you create to maximize your client's function, performance and reduce their chances of injury. The use of unstable surfaces such as the Core-Tex™ is a critical piece of the environmental puzzle for our customers of all ages and ability levels.
Anthony Carey M.A., CSCS, CES holds a Masters degree in biomechanics and athletic training and is Personal Fitness Professional Magazine's 2009 Personal Trainer of the Year. He is the owner of Function First in San Diego, California which was voted one of San Diego's "Best Of" Personal Trainers/Studio for 2010. Anthony has authored two best selling books; The Pain-Free Program: A Proven Method to Relieve Back, Neck, Shoulder and Joint Pain and Relationships and Referrals: A Personal Trainer's Guide to Doing Business with the Medical Community. His work has received national attention, including the New York Times, Time Magazine and Oprah's "O" Magazine.
Anthony presents and writes internationally for the fitness community on biomechanics, corrective exercise, functional anatomy and motor control and their relationships to musculoskeletal pain and function. He consults for the some of the largest equipment manufacturers and health clubs in the world and is the inventor of the Core-Tex™ .
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