The instability of Bosu ball provides additional challenge and benefits to plank exercises. Plank on Bosu ball exercise makes your core abs muscles work harder and develops more strength, balance and flexibility. Bosu ball planks engage all the muscles in your core, obliques and abs. Bosu style ball plank engages all your torso and pelvic muscles in the workout and activates the front of your abdomen. You have to keep your spine neutral throughout the exercise in order to get the maximum benefits of the workout. Planks exercises are specifically beneficial for spine and lower back muscles. It’s recommendable to discontinue the workout if feel any pain or discomfort in any related joint or muscle.