If you want to tone and strengthen your triceps, at the back of your upper arms, make close-grip push-ups part of your strength-training routine. A study sponsored by the American Council on Exercise showed that this type of push-up is one of the most effective exercises for your triceps. It also works your chest and shoulders and engages your core and upper thighs to stabilize your body. For optimal results, master the proper form and modify the push-up to meet your fitness level.

Warm up with five to 10 minutes of low-intensity cardiovascular exercise to get your blood flowing and to prepare your body for the work to come. Go jogging, ride a bike, pedal an elliptical machine, jump rope or do jumping jacks.

Get down on all fours and position your hands directly under your shoulders or slightly narrower. The closer your hands are together the harder the exercise and the greater the emphasis will be on your triceps. Spread your fingers on the floor to make stabilizing somewhat easier. If desired, form a heart, diamond or triangle shape with your thumbs and index fingers, which will increase the difficulty.

Tighten your abdominals to support your back, and then extend your legs out behind you and prop up on the balls of your feet. Don't sag your torso to the floor or push your hips up. Contract your glutes and quadriceps to help keep your body straight as a plank.

Bend your elbows, keeping them firmly at the sides of your torso, and lower your chest toward the floor as you count to three. Stop lowering when your chest is about two inches above the floor and your upper arms are nearly parallel to the floor.

Extend your elbows and push yourself up to the starting position in about half the time it took you to lower yourself. Imagine pushing the floor away from you, and keep your body straight as a plank the entire time. Immediately go into the next repetition.