Overhead extensions are a tricep exercise. The triceps are located right above the elbow on the backside of the arm and they are being worked any time the arm is straightening, or "extending." Increasing the size of the triceps muscles can help tighten the skin around the elbows. To perform an overhead extension, hold a two light dumbbell in each hand. Extend them straight over your head as if you are signaling a touchdown. Now slowly lower them behind your head and lift them back up. Make sure to keep your upper arms still and tight against your ears the whole time.
Tricep pushdowns are done on a cable machine. Attach a straight bar to the high pulley and place your hands on the bar about shoulder-width apart. Stand with your back straight, keep your upper arms tight against your body, and then push the bar down until you reach your thighs. Make sure to not let your arms move in and out.
To do dips, take 2 chairs and space them about the length of your legs away. Place your hands on the edge of one chair and your heels up on the other one. Lower yourself down by bending your elbows. Come to a point where your elbows are at an angle of about 90 degrees, then push yourself back up.
Push-ups are a classic elbow extension exercise that works your chest and arms simultaneously. These can really tone up the back of the arms and tighten the skin. To perform them, come into a plank position with your hands directly under your shoulders, your arms and back straight, and your toes on the ground. Slowly lower your body down towards the floor while maintaining a straight posture. Let your chest get about a fist-width away from the floor, then push yourself back up to the starting position.
Bicep curls are performed by bending the elbow and bringing the lower arm towards the body. This is also called "flexion." To do a straight bar curl, attach the bar to a low pulley on a cable machine. Grab the bar with a shoulder width grip and curl it up by bending your elbows. Bring it up until it is about chest level, then lower it back down.
Bicep curls can also be done with dumbbells. Grab the dumbells and let them rest by your sides facing your body. Curl them up in the air and rotate your little fingers inward. Stop when you get to the level of your chest, and lower them back down.