Sit-ups are a functional exercise which mimics sitting up from a lying
position. Adding medicine balls to sit-ups increases the difficulty by adding
resistance. Extending the arms during the sit-ups also works the triceps and
anterior deltoids. Placing your feet under something or having a partner hold
your feet to the floor makes medicine ball situps easier while performing them
without anchoring your feet to the ground increases the challenge. These
medicine ball sit-ups can be performed alone or with a partner or trainer and
can be modified by adding throws, rebounders, etc.