The Swiss ball, also known as an exercise ball or a gym ball, is a training aid aimed primarily at the stretching and strengthening of the abdominal, groin, lumbar (lower) back, and upper leg muscles of the body. The development of these structures is often referred to as the building and maintaining of core strength, an important stabilizing feature in any sport.
Swiss balls are inflatable, and they are typically filled approximately 80-90%. The ball is constructed from a thick rubberized compound, available in differing sizes. For optimum effect, a Swiss ball should stand approximately 2 in (5 cm) above the user's knee from the surface.
The Swiss ball permits a range of exercises that are based on the ability of the user to move with the motion of the ball while performing the exercise, using the ball to both support the body during the movement as well as to provide a measure of resistance to the muscles employed in the movement. The classic Swiss ball exercises involve the abdominal muscles, with corresponding responses from the groin and the stabilizers of the lower back, the oblique muscles that run parallel to the spine above the pelvis. The athlete, positioned on top of the Swiss ball, can take the abdominals through a complete range of motion through the performance of crunches (a motion that brings of the upper thighs and the sternum [breastbone] toward one another, to strengthen the abdominals); twisting crunches, where the upper body twists in opposite directions during the crunch to extend the muscular effect across the abdomen; and the flexion of the thoracic spine, the vertebrae of the mid-back to improve overall flexibility.
Swiss ball movements require a greater degree of coordination by the user than do conventional floor stretches. The Swiss ball also permits the execution of both static stretches (where the target body part is fully extended), as well as more demanding dynamic stretches, where the user directs force into or through the extended joint.
While a Swiss ball routine may have both aerobic and anaerobic benefits, depending on the intensity, duration, and the frequency with which the exercises are performed, Swiss ball training is not a substitute for either type of exercise. The Swiss ball is an ideal supplement to an existing training program, such as yoga or Pilates, which promote greater strength and flexibility in a safe and controlled physical setting.