Gorilla Crunch

Hang from a chinning bar with your knees bent at a 90 degree angle and your hands about 12 inches apart with an underhand grip. Pull yourself up with your arms and crunch your knees up at the same time. You should finish the chin and crunch at the same time. When fully contracted, your note will be at the bar and your knees will be pulled up to your chest. Slowly reverse the movement and return to the starting position. You can also do this with a dumbbell or medicine ball between your feet or with a weight attached to a dip belt around your waist. When you have mastered this, try hanging from only one arm and grasp your wrist with your free hand. This works more of your obliques