Photo credits: James Michelfelder.
1. Sit under a barbell. Hold the bar (alternatively, you can use a pair of dumbbells) overhead with an overhand, shoulder-width grip. Lie back on the floor.
2. Press the bar overhead, then reach back over your head, bending your elbows only slightly. Continue until you feel a stretch in your lats, then pull the bar back over your chest, flexing your triceps as you go.