You can tone and firm your abs (and work on getting that six pack) with this exercise!   You’ll increase the strength of your abdominal muscles not to mention increased stability, balance, and core strength, which enhances any activity.  Obviously you can also perform this exercise on a mat or a flat bench; however the bosu works deeper into the abdominal muscle and targets the total trunk musculature (core) incorporating balance and stability, which makes the exercise more challenging and with better results!

• Sit on the lower edge of the Bosu with feet flat on the floor.
• Lean back until lower and mid back is resting on the center of the Bosu.
• Place hands behind head; keeping elbows back and chin up.
• While keeping abdominals engaged (tightened and drawn in) exhale out and crunch up.
• Inhale as you lower back onto the Bosu.
• Beginners do 2-3 sets of 10- 15 repetitions.
• Intermediate/advanced do 3 sets of 25-30 repetitions.