4. Ball slams

teresacore_ballslam.jpg

Core, Shoulder, Back 

Stand with your knees slightly bent and hold a medicine ball overhead, with your arms extended. Bend forward at the waist and use your core muscles to slam the ball against the floor about a foot in front of you. Retrieve the ball and repeat as many times as you can in the recommended amount of work time.

NEXT: Lunges and overhead press