Start: Lie lengthwise on a bench-not perpendicular to it, as you often see in gyms. Press your head, torso, lower back, and glutes firmly against the surface. Your feet should be flat on the floor. Place one hand around the handle of a dumbbell and wrap the other one over the gripping hand. Extend your arms directly above your collarbone, holding the dumbbell bar perpendicular to the floor.
Finish: Keeping your back flat against the bench to elongate your lat, slowly lower the weight behind your head until your arms are in line with your ears. Pause, then pull the weight back up. Slightly bend your elbows throughout.