The term "Swiss ball" was coined because one of the earliest noted uses of an exercise ball was in Switzerland in 1965, where a group of physical therapists used it in their work with children with cerebral palsy. The exercise ball may also be referred to as:
- Gymnic ball or gym ball
- Stability ball
- Therapy ball
- Physio ball
- Blue ball (because many are blue).
The size of exercise balls varies. Physical therapists and exercise trainers suggest using an exercise ball that fits each person's height and leg length, where the hips and knees are at or slightly greater than a 90 degree angle (thighs parallel to ground or point down slightly) with feet flat on the floor. It is best to work with a physical therapist, exercise physiologist, or other spine specialist for a proper fit before using or purchasing an exercise ball.
The exercise ball may be inflatable, made out of vinyl or plastic or solid foam rubber. Inflatable exercise balls can be punctured, so it is best to avoid wearing anything sharp (such as jewelry or a belt buckle) when using the ball. Exercise balls made of plastic can be harmed by exposure to heat or excess sunlight. Certain manufacturers claim designs that stop the exercise ball from exploding if a puncture occurs, allowing the air to leak out slowly instead.