Exercise gym balls / stability balls offer a dynamic training environment for a variety of exercises at different levels of intensity. The stability ball was originally designed for use in the rehabilitation of patients with neurological disorders and spinal injuries. Resist-A-Ball® crossed over into the fitness arena and has become a "must have" piece of training equipment for nearly every personal trainer and fitness professional. Mike and Stephanie Morris rolled out the Resist-A-Ball® program to the fitness industry in 1993, introducing the stability balls into their personal training and group exercise workouts. Today Resist-A-Ball® training products and education can be found in many health clubs and homes throughout the world.