Most people will benefit from both free weight and instability training (on unstable surfaces) to promote spinal stability. It’s important to remember to decrease resistance loads on exercises performed on unstable surfaces.
During rehabilitation, unstable surfaces can be effective at improving muscle reaction time and co-contractions that protect joints. In addition, resistance training on unstable may provide localized muscle endurance training, beneficial for the high proportion of Type I “aerobic, slow-twitch” muscle fibers found in core muscles. Core endurance training exercises generally can be performed at higher repetitions (greater than 15 per set), while athletes requiring more strength and power perform less than 6 repetitions per set. Unstable surface training can provide musculoskeletal health benefits such as decreased injury risk and increased spinal stabilization as opposed to using free weights alone.
In summary, unstable exercise devices such as Thera-Band Exercise Balls and Stability Trainers should be included as part of a well-rounded conditioning program for athletes and non-athletes, but not for increasing primary strength and power. In addition, resistance exercises performed on an unstable surface should be performed at a reduced intensity level because of the reduction in force output.