Your desk job, commute, and couch time can seriously screw up your posture. Instead of walking tall and proud, you now sport a permanent slump.

But looking like a caveman isn't your only problem. Over time, poor posture can take a toll on your spine, shoulders, hips, and knees, reducing mobility, causing pain, and limiting your ability to lift weights, says BJ Gaddour, C.S.C.S., creator of Men's Health StreamFIT.

To save your posture and build a better body, try the side-lying windmill.  "It's a simple way to mobilize your shoulders and upper back,"  Gaddour says. Do it during a warmup, before an upper-body exercise, or on a rest day. Watch the video to learn how to perform the side-lying windmill with perfect form.