Sculpt and injury-proof your body with these 4 muscle builders

from menshealth.com

"Most men spend time training what they see in the mirror and neglect their back, rear shoulders, hamstrings, and glutes," says the Men's Health Muscle Guy, Mike Mejia, M.S., C.S.C.S. But just because you aren't looking doesn't mean she isn't. Rebalance your body with highly effective exercises to strengthen those weak spots. Perform all four moves without rest. Break for 90 seconds and repeat the circuit two more times.

1. Swiss-ball leg curl
Lie on the floor with your calves on a Swiss ball. Raise your hips so that your body forms a straight line. Pull the ball toward your butt with your legs, pause, and roll the ball out. Do 10 reps. More