The crunch on exercise ball is an exercise targeting the abdominal muscles, particularly the rectus abdominis or six-pack muscles. The exercise is performed by lying on an exercise ball with your knees bent and feet flat on the floor. You then curl up, bringing your knees toward your chest and squeezing your abs at the top. You then lower back down and repeat. The exercise ball provides instability, which challenges your core muscles and helps to improve your balance and coordination, This exercise is a great way to strengthen your abdominal muscles and improve your overall fitness. It is also a relatively easy exercise to perform, so it is a good option for beginners or those who are looking for a lowimpact workout, Here are some tips for performing the crunch on exercise ball, Start with your knees bent and feet flat on the floor, Place your hands behind your head or on your chest, Inhale as you curl up, bringing your knees toward your chest and squeezing your abs at the top, Exhale as you lower back down, Repeat for the desired number of repetitions, You can make this exercise more challenging by adding weight or by doing it on a harder surface. You can also make it easier by bending your knees more or by using a smaller exercise ball.