Dr. Laskowski: The triceps extension is an exercise you can do with a weight machine to work the muscle in the back of the upper arm. As the name implies, the triceps extension targets the triceps muscle, located here in the back of the upper arm. Properly done, the triceps extension helps strengthen and tone the back of your upper arm. If you use a cable system, you can also work your core muscles and improve your stability.

Nicole Campbell: To do a triceps extension with a weight machine, start by gripping the bar with your elbows bent and palms facing down. Make sure your elbows are comfortably positioned close to your sides. Slowly push down the bar until your arms are fully extended. Then slowly return to the starting position. You'll feel tension in the muscles in the back of your upper arm.

When you're doing triceps extensions, move your arms smoothly and slowly. Keep your elbows tucked close to your sides. Hold your head, spine and lower body stable but relaxed during the exercise.

For most people, one set of 12 to 15 repetitions is adequate.

Remember, for best results, move your arms smoothly and slowly during the exercise. Keep your elbows tucked close to your sides.