I am often asked about the use of STABILITY BALLS, Bosu balls and other balance devices and whether they’re good, bad or ugly. Here is my overview:-

Abdominal Strength and Rehabilitation

Although there is conflicting research, the bulk of the evidence suggests that stability training will significantly activate the muscles of the abdominal wall, improving both local muscular endurance and stability in this area. For rehabilitation, stability devices have been shown to increase muscle activation without the muscle having to produce as much force-which is exactly what is needed for rehabilitation. Ground based exercises like squats and dead lifts  provide great core muscle activation, but people with lower back injuries for example often have impaired neuromuscular coordination (coordination of nerves and muscles to bring about movement) and struggle with these movements.  In such cases training on stability devices has been shown to be a safe and effective alternative.

Strength and Power

Strength and power generation is dependent upon the optimal recruitment of motor units (nerves and the muscle fibers they activate). These recruitment patterns are developed optimally on a stable surface that facilitates a constant and even distribution of force. As has been established, training on stability devices increases muscle activation, but decreases muscle force. Over time, training on stability devices can alter muscle recruitment patterns (Hubbard, Daniel MEd, Strength and conditioning Journal 2010). The net result is an impaired ability of the muscles to generate force when training on stable surfaces. So, not good news for anyone training for strength, power, hypertrophy etc.

So, what’s the verdict?

For rehabilitation and core stability, stability devices definitely have their place.  I also believe they have some application in developing symmetry, eg in the case of the strength or muscular coordination of one limb being significantly inferior to the other. It may however be argued that there are a number of other ways of developing symmetry using unilateral, ground based movements, without the potential detrimental effects to overall strength gains.

For general fitness in which you want to work with low intensities (weights) and high volumes, they also have an application. If you consider for example that your core musculature is made up largely of endurance type fibers, working on an exercise ball or Bosu ball with low resistance and high volume workouts will definitely develop your core. You can incorporate stability devices from time to time if general health and fitness is your goal, and I would focus on upper body and ab exercises.

If you are squatting with heavy weights on a Bosu ball, PLEASE STOP. You’re hindering your progress, and risking life and limb in the process!

I can see no application to anyone wishing to make gains in strength, power or hypertrophy. In fact, you’re slowing your progress (particularly for lower body work).

So, like most things, stability devices are not evil, and they are not the be all and end all. The important thing is, to know what your goals are and how to incorporate the various training tools into your routine to achieve those goals.