Should You Ever Do Exercises On an Unstable Surface?

Exercises performed on stability ball:

Chest: single arm dumbbell bench press
Back: seated cable rows
Shoulders: dumbbell press
Triceps: French press
Biceps: dumbbell hammer curl
Trapezius: seated mid row retraction
Abdominals: crunches holding medicine ball
Rotator cuff: seated dumbbell horizontal external rotation
Legs: dumbbell Bulgarian split squat with rear foot on stability ball

I was not able to do as much weight with the exercises on the stability ball as I could without the stability ball. Although I came close in some (the Bulgarian squat, French press, and hammer curl), others were much more difficult to perform on the ball (single arm dumbbell bench press, dumbbell rows).

In general, the two-arm exercises I attempted on the ball were much easier than the single-arm exercises. Sitting on a stability ball while doing a cable row was a challenge for my balance and brought my legs into the movement to stabilize my body. Attempting to do a single-arm dumbbell bench press on the stability ball was close to impossible, however, with any weight close to what I would be able to do on a solid surface.

The reason that the difficulty level of each exercise was increased was probably due to a number of reasons. First of all, without having done a lot of stability ball weightlifting in the past, my body has simply not yet adapted to this type of movement.

The SAID principle would suggest that, by utilizing exercises on the stability ball on an ongoing basis, I will have neurological and muscular adaptations to the exercise. Because I was doing these exercises on a ball for the first time, they may have been more difficult due to the lack of nervous system adaptation to the movements.

Also, muscles that used to put force into the ground or stabilize my body for some exercises were now actively working against the instability of the ball. My movements were slower and I was using less weight because the surface felt so precarious compared to solid ground.

The use of weight training while using an unstable surface seems to be a growing trend in gyms that I have been to. But what types of exercises should be performed on stability balls, medicine balls, bosu balls, wobble boards, and other similar equipment?

For upper body exercises, I can see some value in using an unstable surface. The upper body is not always in contact with solid ground during athletic movements. In fact, in many sports, instability is the rule much more than the exception. From playing basketball or football, or MMA fighting or wrestling, athletes often interact with other athletes in physical activities where it is difficult to predict what the next person will do. For these types of activities, some unstable upper body training could be useful.

However, the lower body is rarely off of a solid surface in many sports and in most periods of daily life. An unstable surface is not necessary to work the stabilizer muscles of the legs, as well. Single-leg exercises such as lunges, step-ups, or Bulgarian squats can strengthen an athlete’s balance while remaining on the stable ground.

If a client is coming in for training to perform better at a sport such as skateboarding or surfing or another activity that is routinely done on unstable surfaces, then some leg exercises using a stability ball or wobble board may be appropriate to simulate the stability needed for that sport. In general, though, lower body training should primarily be done with at least one leg connected to a solid surface.

The use of unstable surfaces for lower body exercises may be appropriate for rehabilitation from an ankle injury. This is a joint that may be able to benefit from instability training with lighter weights. Clients with weak ankle strength or prior injuries may also find these exercises appropriate for building strength and improving balance.

Thus, instability training should only be used in certain circumstances. For athletes engaged in competitive sports with a large amount of unpredictable movement and contact with others, upper body exercises may be prescribed. Unstable surface exercises for the lower body may be used for people who engage in sports that are not done on solid ground (skateboarding, surfing). This type of exercise can also be beneficial for those with prior ankle injuries as a rehabilitation for the joint.

For most other people, it would be difficult to think of an opportunity when lower body weight training on an unstable surface would be recommended. Most people spend their athletic and non-athletic lives in contact with solid ground, so it does not seem to make sense to have them train against resistance with increased instability. If balance or muscle imbalances are to be addressed, single-leg exercises may be more effective and safer.