Start: Hold a stability ball in both hands, and lie back on a mat with arms extended overhead, legs straight.
Move: (A) Slowly crunch upper and lower abs together by raising arms and legs to meet above stomach. (B) Place ball between feet, then lower arms and legs back toward floor. Keep muscles contracted, allowing arms and legs to slightly touch the floor―if at all. Reverse the move by lifting legs and arms back to center, moving the ball to hands, then extending arms overhead and legs back to floor for one rep.
Repeat: Perform two sets of 10 to 12 reps with one minute of rest between sets.