This exercise tones and strengthens the triceps (muscles in the back of the arm).  Try to squeeze elbows together as you straighten arms; this will help keep your upper arms stable.

• Attach either a “W” or a straight bar to a high-cable pulley machine.
• Stand with your back to the weight stack, feet separated in a staggered lunge stance with heel up on the back foot, placing feet about a foot apart.
• Keep abdominals contracted (drawn in), chest lifted and shoulders down.
• Grasp bar with an overhand grip, hands separated shoulder-width, then bend elbows so upper arms are near your jawline and bar is overhead, wrists neutral, squeezing shoulder blades down and together.
• Keeping upper arms stable (motionless) and abs contracted; straighten arms to full extension without angling torso forward.  Keep elbows in (try not to flare them out).
• Slowly bend elbows to starting position, then repeat.
• Do three sets of 12-15 repetitions.