The Swiss ball crunch increases muscular strength and endurance throughout the core region including the lower abdominals, lower back, and hip flexors. Performing the exercise on the Swiss ball will also increase balance and stability. Adding the Swiss ball has two main benefits. First it improves the range of motion on extension (the lower of the crunch), which build abdominal strength. It also positions the body in a way that tends to place less stress on the upper and lower back.