Vern Gambetta, MA, is the President of Gambetta Sports Training Systems in Sarasota, Fla., and a frequent contributor to Training & Conditioning. His daily thoughts on training athletes can be viewed on his blog:  

Training & Conditioning, 16.6, September 2006
From sand to wobble boards, unstable surfaces are everyone’s newest training device. However, it’s important to understand your performance goals before you start getting tipsy.
Fifteen years ago, I first experimented with unstable surfaces, and I very quickly liked what I saw. I noticed that athletes rehabbing ankle sprains and ACL tears with unstable surfaces seemed to have better functional balance and body control. I felt that if we could incorporate what they had done in rehab into training for healthy athletes, we should see similar gains.
Initially, this was the case. I did not devote much time to this training, maybe five or 10 minutes a day, but seemed to get good returns. As often happens, I decided that more had to be better. So I began to seek out more exotic unstable surfaces—the more unstable the better. At the time, it seemed to be a great way to achieve overload.
But as I continued to experiment with the concept, I became uncomfortable with the direction I was heading. I saw that instead of making the athletes better, all the work on unstable surfaces was taking them further and further away from the performance arena. They were learning tricks, not functional movements. The exercises became an end to themselves.
Since my introduction to them, unstable surfaces have become very popular. Coaches use them in many different situations, but not always with a lot of thought behind their purpose.
In this article, I hope to bring a degree of sanity—and balance—to the use of unstable surfaces.

What Is the Goal? Most of the research regarding the use of unstable surfaces comes from the rehabilitation arena. There is good evidence to suggest that these surfaces are effective for both injury prevention and rehab situations.
The November 2001 issue of the Journal of Orthopedic& Sports Physical Therapy includes a very good article on ACL injury prevention through a balance routine. High level soccer players were given a 20-minute workout, performed daily, using apparatuses like a K-board and wobble board. Of the 300 players who performed the exercises, 10 suffered ACL injuries over the next three seasons compared to 70 in the control group, which also consisted of 300 athletes.
The authors’ theory was that using these two pieces of equipment produced quick ankle movements similar to those that occur on the field at the time of an ACL injury. The sensory input in terms of improved kinesthetic sense and improved proprioception was thought to help prevent the injury. The results were pretty convincing and showed a good return on the time invested using simple exercises.
Athletic trainers and physical therapists have also made great progress in using unstable surfaces for rehab. Many articles promote the use of rehab protocols that utilize unstable surfaces. The key in rehab is that the devices produce controlled instability and exercises are performed in a very systematic and progressive manner.
However, the question I want to explore is: How can unstable surfaces best be used to enhance performance? There is not much hard data in this area, and most results are basically anecdotal.
To start, let's ask ourselves why we would deviate from a flat surface in our training. What is the goal in using an unstable surface?
In most cases, we are trying to challenge the proprioceptive system and thus make it better. When the body senses a change in surface, it will self-correct to achieve appropriate positions for the movement. These rapid adjustments are based on the proprioceptive input that detects speed and stretch. The body’s proprioceptors act as very sophisticated motion sensors, and it is this motion detection function that we are attempting to train by using uneven surfaces. If we can improve body awareness and spatial awareness, the result should be an athlete who has more balance and more athleticism on the field of play.
But how unstable should the surface be to challenge our athletes? An unstable surface is any surface that the body perceives as unstable. In fact, the body is sensitive to even small changes in surface. To the eye, a surface may appear stable, but if the body proprioceptively perceives it as unstable, it is.
In most sports, the ground does not move from under us. (Surfing, water skiing, wind surfing, and skiing to a certain extent are examples of sports where the ground does move under the athlete.) The instability in a surface is very subtle, such as a slightly bumpy field. If we train our athletes on surfaces that differ too much from the normal competition surface, there is a risk of developing a skill set that is not needed. If the stability gains do not transfer to the field, it is a waste of time to develop them.
A good example is training athletes to balance while standing on a physioball. Except for a very few sports, there is no carryover. It is a discrete skill that does not translate to a sport skill. That time would be better spent doing more sport-appropriate activities.

New Thinking I’m not trying to say that unstable surface training is inherently bad. First of all, it has a definite place in injury prevention and rehab. Second, I still agree with the idea of developing proprioception through unstable surfaces. However, I would urge you to think deeply about the surface you are using and why.
When it comes to performance enhancement, the key is the application. Will the movement transfer? Is the movement sport appropriate? If it is sport appropriate, it will have some carry-over to the sport. A quick rule of thumb I use is: If the athlete has to spend undue amounts of time learning a new skill set in order to train with unstable surfaces, it is not sport appropriate.
By a new skill set, I mean skills that exaggerate movement through significantly larger amplitudes and speeds that are not similar to sport movements. And just looking similar to sport movements is not good enough. The speed and angles must be in the range that will be used on the field.
To use unstable surfaces in a way that will transfer to improved performance, a sound approach is to begin to create instability through movement itself. In many cases, the normal environment is enough. Just stepping and hopping, and jumping and sticking the landing, are two examples. Then, you might progress to using an inclined surface like a hill.
Next, consider employing a few environmental modifiers. An environmental modifier is anything that creates an increased proprioceptive demand and also transfers to the movements of the sport. So the question you must ask yourself is: What will transfer? And what will create a skill set that doesn't transfer?
Success or failure in most ground sports depends on how effectively athletes are able to use the surface they compete and train on. The surface can give back energy or dampen force. When you consider unstable surfaces, use those that teach the athlete how to use the surface to his or her advantage.
Explore the simple and obvious before going to the complex. For example, shoes are worn to protect the foot during ground contact. Therefore, perhaps the simplest way to increase instability is to do some activities barefoot. Because of the abundance of proprioceptors in the bottom of the foot, this affords the possibility for heightened sensory input. Working barefoot will have a quick and obvious transfer.

Ready to Wobble With an understanding of the true purpose of unstable surfaces for performance enhancement—as well as the limitations—you can start incorporating them into your workouts. In most cases, they should be placed within the body of the actual workout, probably done alongside agility work or lower-body strength training.
Let’s take a look at a sampling of unstable surfaces coaches use for training:
Sand is a viable unstable surface, although it has some limitations. On the positive side, it enables big angles and aggressive movements that allow the athlete to push the edge. The primary downside is that the softness of the sand slows everything down significantly. It dampens the elastic response, which is both a plus and a minus. It is a plus because it develops good concentric strength response. It is a minus because it negates elastic response, so it is not real life.
Large pits, such as high jump and pole vault pits, dampen impact and should not be used extensively. The depth of the pits virtually eliminates any elastic response, and work done in them will be dominated by concentric muscle action. Pits are good for repetitive jumping, some running in place, and some planting and cutting, but I do not use them more than twice a week for a six-week block of training. And I always follow any pit work with one or two drills on a stable surface.
Trampolines are obviously bouncy and very responsive, which is good for body awareness and control. A trampoline is a good surface to work on landing and sticking a position to create stability.
Exercise floors are very springy surfaces, which provide a very predictable response with some give. They are a good surface to work on barefoot.
Wrestling mats are not as responsive as exercise floors, but are another good surface for barefoot work. They can also be used for multidirectional activities because of the size of the mat.
Foam pads, especially those that are small and high-density, are good for static balance activities. The level of instability can also be easily controlled by using different pads.
K-boards are nice for side-to-side instability. The pivot point of the board allows movement in the frontal plane only. Use them for static balance in an athletic stance with the knees slightly bent. Build up to three to five 10-second holds without the edges of the board touching the floor.
Another good exercise is a single-leg balance with the foot parallel to the pivot point. Hold 10 seconds, switch legs, and repeat three times. Repeat movements with the foot perpendicular to the pivot point.
Wobble boards have a pivot allowing 360-degree movement, which creates rotational instability. Here are three drills to use:

• Standing on the board with two feet, rotate the board 360 degrees clockwise touching all the edges. Repeat counterclockwise.

• Standing on the board with two feet touching the edge of the board, move feet to 12 o’clock, 3 o’clock, 6 o’clock, and then 9 o’clock. Repeat back, reversing the order.

• Do a single-leg balance in the middle of the board. Hold 10 seconds, then switch legs. Do three 10-second holds with each leg.

BOSU balance trainers can be used like the wobble boards, with the same exercises. Using the flat side allows 360 degrees of motion as well as a tipping effect. The degree of instability is determined by how inflated the BOSU is. Most of the time it should be fairly well inflated.
Leather medicine balls are great to step on to and off of, or from one to another in a stepping stones pattern. They are very effective when combined with several BOSUs.
Balance beams allow movements forward, back, and side to side. They are also an effective platform for single-leg squats. The edges of the beam should be beveled to create a bit more instability.
The key to using unstable surfaces is understanding that not all apparatuses are appropriate for all situations. A good craftsman knows how to effectively use the tools in the toolbox—a hammer cannot replace a screwdriver. These surfaces and apparatus are analogous to the skilled craftsman’s tools for the coach. Use them sensibly, remember more is certainly not better, and be very specific about your goals.

Table: A Balanced Week The following is a sample workout using unstable surfaces during one full week of training.
Monday Single-squat balance: Do a one-leg squat with focus on balance.
Balance shift: Hold each of the following positions for 10 counts:
• Shift from the center. The upper body should be quiet.
• Step right shifting weight onto right leg.
• Step left shifting weight onto left leg.
• Step forward shifting weight onto right leg.
• Step forward shifting weight onto left leg.
• Step back shifting weight onto right leg.
• Step back shifting weight onto left leg.

Wobble board storks (Advanced): Stand on one leg with the non-support leg bent. Hands should be out in front or overhead. Perform a single-leg squat by balancing on one leg and squatting down, proportionally bending at the ankle, knee, and hip and holding the non-supporting leg flexed with thigh parallel to the ground. Hold at the bottom position for 10 counts. Use three different positions:
• Straight ahead (free leg pointing straight ahead).
• Side (free leg reaching out to side with knee straight).
• Rotation (free leg rotating at hip to face to side).

Tuesday Wobble board rolls: With both feet on the board, rotate clockwise touching the edges of the board. Repeat counterclockwise.

BOSU rolls: Use the same instructions as for wobble board rolls, using a BOSU ball.

BOSU single-leg balance: Balance on one leg in the middle of the board.

Wednesday Single-squat balance

Balance shift

Wobble board storks

Thursday Wobble board rolls

BOSU rolls

BOSU single-leg balance

Friday Single-squat balance

Balance shift

Wobble board storks

Saturday Wobble board rolls

2. Do most athletes understand the correct way to train so they build up rather than breakdown the body?
Surprisingly, many athletes are unsure of how to correctly train their bodies, and I often find it challenging to teach proper form with exercises. Posture and body mechanics are big issues, for example, keeping the back in proper alignment, bracing the abdominal muscles, and avoiding internal rotation at the hip joints with functional activities.

3. Has being a certified athletic trainer (ATC), physical therapist (PT), and certified strength and conditioning specialist (CSCS) given you an edge in working with your athletes and patients?
Most definitely, especially with years of athletic training education, training, and work experience. I’ve been fortunate to have the opportunity to work in-depth with athletes at all levels. Part of my unspoken philosophy in treating injuries to my current patients, old and young alike, is to treat all like an athlete. I know how to get an athlete back into competition sooner, rather than later, with a safe yet aggressive rehabilitation program, and I’ve been able to teach and encourage non-athletes into achieving things that they did not think possible.

4. What is your list of exercises that you would like to see people eliminate from their routines?
Number one on my list is the typical knee extension machine that is found in most gyms, and, believe it or not, in many physical therapy clinics. The action of extending the knee in an open kinetic chain (which basically means the foot is not fixed to a stationary object) with resistance, puts an incredible amount of stress on the knee. In addition to being a “knee killer”, this exercise strengthens the quadriceps in a non-functional way, which limits its effectiveness.

In addition, I’d also like to see the traditional sit-up exercise replaced with lower abdominal training and lumbar stabilization exercises. It’s amazing how strong and stable the trunk can become in the absence of sit-ups, which potentially put strain on the ligaments of the low back.

5. When a person is injured, what can he/she do to maximize the rehabilitation process?
Don’t delay treatment! The sooner an injury is treated, the sooner it will feel better. It is those chronic injuries that have been left untreated for weeks, months, or even years that are the hardest to treat. Part of the reason why so many athletes at the collegiate and professional levels bounce back so quickly is because they have a team of athletic trainers who treat their injuries immediately.

6. Are you seeing an increase in injuries from overuse (repetitive strain and sprain) in younger children since the start of your career?
Absolutely. Part of the reason may be because the early part of my career was spent working exclusively with collegiate athletes, whereas nowadays I work with all ages, including children and teenagers. I have seen numerous young athletes, more females than males, who develop chronic knee pain especially. I believe the reason for this is that young athletes often play sports every season of the year. They sometimes play more than one sport at a time in each season, and they have no rest periods in-between seasons. Also, youngsters are specializing in a sport at a younger age, which I believe is a big mistake. I am of the opinion that children need to have fun, play no more than one sport per season, allow their bodies to rest when they hurt, and avoid specializing in one sport until later high school at the earliest.

7. Do you have a list of exercises that seem to get great results for a broad spectrum of athletes?
I’m a big proponent of “functional” exercises, exercises that mimic actual motions that an athlete will need to perform. Most of these exercises are termed “closed kinetic chain” exercises, which basically means that the foot is fixed as the exercise is performed. For example, squatting, lunging, and step exercises involve the foot being fixed to the floor or a step as the exercise is performed. I am also a fan of core stability exercises, and I like to utilize simple pieces of equipment such as a Swiss ball, weighted plyoball, and body blade to work this region of the body.

8. What do you see as possibly the causes of the fitness crisis in North America?
I think it’s a combination of a sedentary lifestyle and poor nutritional choices. Children especially appear to be much less active than when I was growing up. Instead of impromptu games of catch and kickball, I see kids staying inside and playing video games, surfing the internet, and watching television. Chips, cookies, and soda are the snack foods of choice for many, rather than more healthful options.

9. What advice do you have for coaches in regards to training athletes?
My advice would be to seek the guidance of a professional, whether it’s a certified athletic trainer, or a strength coach. In the absence of such services, I would advise doing some independent reading and studying on the topic, attend a weekend course, and even take a sports medicine or conditioning class for college credit.

10. What advice do you have for parents in regards to their child’s participation in sports?
Let your kids have fun. Encourage participation in a variety of sports; downplay competition. Don’t push them into undertaking too much at once. If your child has an ache or pain, seek professional advice as needed, and give them the time needed to rest and recover.

11. For senior athletes, what do they need to consider from a physiological and biomechanical point of view?
One thing that I always stress to my senior-aged patients is that with a strength, flexibility, and/or balance program, they can show the same degree of improvement as do younger athletes. When comparing a 20 year old vs. an 80 year old, the 20 year old may have more physical strength, but if both athletes are put on a program, they will typically improve at the same rate.

12. How can athletes develop a daily regime without over-training?
A big thing is to follow the principles of periodization, or breaking your workout regimen into different cycles throughout the training year, allowing for variety in your routine. Cross-training, or utilizing various methods of training, is important to again incorporate variety into a routine, as well as to work the muscles in different ways, not to mention helping to alleviate boredom with a routine. In addition, periods of rest must be part of an overall training program.

13. With a diagnosis of osteoarthritis, does exercise decrease the lifespan of the joint? If it does, how does the athlete maintain mobility, muscle function, etc. without more degradation? (For example, erosion of the cartilaginous surfaces of the tibia and femur at the knee joint)
Research typically supports the notion that an injured joint, specifically with osteoarthritis, needs exercise to maintain or even improve joint health. Osteoarthritis itself is irreversible, but by keeping the surrounding musculature strong and flexible, the long-term prognosis is much brighter. An individual suffering from osteoarthritis needs to “listen” to his/her body, and stop a particular exercise if it is increasing his/her pain levels.

14. Do you think that athletes use over-the-counter pain medication too frequently to continue to play?
In my own experience, I have found that athletes used over-the-counter pain medication/anti-inflammatories more frequently 10 or so years ago than they do today. Under the direction of a physician, NSAIDs (non-steroidal anti-inflammatories) are appropriate in the overall treatment plan of certain injuries; it is the athletes who self-medicate, and perhaps overuse medications, that concern me.

15. Is there anything you would like to comment on that I did not ask?
I’d like to commend you on your approach to training and conditioning, and wish you well. It is important for people to be educated consumers in many facets of life, and this applies to the field of strength and conditioning as well. Before undergoing a fitness program, individuals should check to be sure that the professional with whom they’re working is certified by a highly respected organization (NSCA, ACSM); for athletes who need to undergo a rehabilitation program, I’d advise that they seek out a “sports medicine” clinic that is staffed by certified athletic trainers (ATC’s), professionals who are specifically trained in the rehabilitation of athletes.