Stability-Ball Jackknife to Shoulder Press:

Begin with your ankles on the stability ball in the modified plank position. Perform a jackknife by rolling the ball towards your hands, squeeze the abs, locked out knees, and make a peak with the hips. When you hit the top of the jackknife, perform a shoulder press and return to the plank position. REPEAT.

NOTE: If the shoulder press is too advanced, you may also perform a push-up after you do the jackknife.