Slide show: Weight training exercises for major muscle groups

Weight training can boost your strength, tone your muscles and help you lose fat. Ready to start a weight training program?

Warm up with five to 10 minutes of stretching or brisk walking. Then choose a weight or resistance level heavy enough to tire your muscles after about 12 repetitions. With the proper weight, a single set of 12 repetitions can build muscle just as efficiently as can multiple sets of the same exercise.

To give your muscles time to recover, rest a day between exercising each specific muscle group. Remember to complement your weight training routine with daily aerobic activity. Overall fitness will soon be yours!

The chest press is an exercise you can do with dumbbells to strengthen the pectoral muscles in the front of your chest.

Lie on your back with your knees bent and a dumbbell in each hand. Hold your upper arms perpendicular to your body and your forearms perpendicular to the floor. Slowly press the weights upward until your elbows are almost straight. You'll feel tension across your upper chest. Return to the starting position, being careful not to drop your elbows below the surface of the bench. Repeat.

Although the chest press is usually done lying on a weight bench, you can also try it lying on the floor.

The bent-over row is an exercise you can do with a dumbbell to strengthen the muscles in the back of your shoulder.

Start with one knee resting on a weight bench. Learn forward, supporting yourself with your hand. Hold a dumbbell in your other hand, letting your arm hang straight below your shoulder. Slowly raise the weight until your elbow lines up just below your shoulder. You'll feel tension in the back of your shoulder and the muscles across your upper back. Then slowly lower the weight to the starting position. Repeat.

You can also do the bent-over row without a weight bench. Stand with your feet comfortably apart. Then bend your knees and lean forward at the hips.

The triceps extension is an exercise you can do with a dumbbell to strengthen the triceps muscle in the back of your upper arm.

Lie on your back with a dumbbell in your hand. Point your upper arm toward the ceiling, with your elbow bent to 90 degrees. Slowly straighten your elbow, moving the weight upward. You'll feel tension in the muscles in the back of your upper arm. Then slowly lower the weight to the starting position. Repeat. If necessary, use the opposite hand to help keep your arm in a 90-degree position during each extension.

You can do triceps extensions lying on a weight bench or on the floor.

The biceps curl is an exercise you can do with a dumbbell to strengthen the biceps muscle in the front of your upper arm.

Stand up straight with your feet about shoulder-width apart and your knees slightly bent. Hold the dumbbell with your palm facing upward. Slowly curl the weight up by bending your elbow, keeping your elbow close to your body. Then slowly lower the weight to the starting position. You'll feel tension in the muscles in the front of your upper arm. Repeat. For best results, don't swing your arm or elbow. Keep your wrist straight and rigid.

For a core and stability challenge, work both biceps at the same time by alternating arms during the exercise.

The knee extension is an exercise you can do with an ankle weight to strengthen the quadriceps muscle in the front of your thigh.

Secure an ankle weight to your ankle. Then sit on a chair or weight bench, with your feet dangling in a relaxed position. Slowly straighten your knee, pause, and then return to the starting position. Repeat.

You can do the same exercise with a knee extension machine.

The leg press is an exercise you can do with a weight machine to work various muscles in the lower body — the quadriceps muscles in the front of the thighs, the gluteal muscles in the buttocks, the hamstring muscles in the back of the thighs, and the calves — in an integrated fashion.

Adjust the seat of the machine so that your legs are comfortably bent. Place your feet on the platform about shoulder-width apart, and grasp the handles with your hands. Slowly straighten your knees, being careful not to arch your back. You'll feel tension in the muscles in your legs and buttocks. Return to the starting position. Repeat.

The lying hamstring curl is an exercise you can do with a weight machine to strengthen the hamstring muscles in the back of your thighs.

Lie facedown on the weight bench. Position the pad just above your ankles. Slowly bend your knees, pulling your feet toward your buttocks. Only go as far as you can without feeling your pelvis or spine move. You'll feel tension in the back of your thighs. Then slowly return to the starting position. Repeat.

When you're doing lying hamstring curls, use the handgrip for support only. Let your leg muscles do most of the work. Don't pull with your arms or arch your neck or lower back.

Weight training includes exercises that use your own body weight for resistance. The push-up, for example, strengthens the pectoral muscles in the front of your chest and the triceps muscles in the back of your upper arms.

Position yourself on your hands and feet with your eyes facing the floor. Place your hands slightly greater than shoulder-width apart and your feet comfortably apart. Slowly bend your elbows and lower your chest until your chin reaches the ground. You'll feel tension in the muscles in your back, your abdomen and your upper arms. Then slowly return to the starting position. Repeat.

When you're doing push-ups, be careful not to let your back sag down or arch up. Keep your movements smooth and controlled.

The calf raise is a body resistance exercise that strengthens the calf muscles in the back of your legs.

Stand with your feet slightly spread apart, your abdominal muscles tight and your back straight. Slowly rise up onto your toes, as shown here. Pause, then return to the starting position. Repeat.

For greater challenge, hold dumbbells at your sides with your palms facing your body while you rise up onto your toes.

The squat is a body resistance exercise that strengthens the quadriceps muscles in the front of your thighs and the hamstring muscles in the back of your thighs.

Stand with your feet slightly greater than shoulder-width apart and your toes pointing ahead. Slowly descend, bending through the hips, knees and ankles. Keep your back in a neutral position, and don't let your knees roll inward or outward. Stop when your knees reach a 90-degree angle. You'll feel tension in your legs and buttocks. Then return to the starting position. Repeat. If you can't bend your knees to a 90-degree angle, simply go as low as you can.

For greater challenge, hold dumbbells at your sides with your palms facing your body while you squat.