So grab your medicine ball, and let's get going ... especially your lower back, certainly your butt. It's a really great core exercise. 15 more seconds, then we're all done.

Directions: Add one of these exercises to the end of a strength ... reach down toward your toe with the medicine ball, and raise the ball back over your head. Keep your arms straight.

Whether you're working on your deadlift PR, getting ready for a jog, or training for ( gasp!) your first pull-up, warm-ups ...

Tip: Hold a dumbbell or medicine ball for extra intensity ... This means incorporating back-strengthening exercises as well.