The stability ball sit-up is a classic ab exercise. Adding resistance makes it challenging for even a seasoned professional. This exercise is very easy to perform. It is similar to the abdominal crunch, but with a greater range of motion.

First, position the ball on the middle of the back. Place any form of resistance (med ball, weighted bar, dumbbell, etc.) on top of you chest or around the shoulder area. Once the weight is in position, sit all the way up and exhale. Repeat the exercise. Do not rush this exercise.