9781422287033

Make Connections Aerobic exercise gives our hearts and lungs a workout. The term aerobic actually means “with oxygen,” indicating that this kind of exercise depends on getting extra oxygen to the muscles to help them move. Anaerobic exercise, on the other

hand, depends more on burning glycogen, a form of sugar. The word an- aerobic means “without oxygen,” so this kind of exercise doesn’t get you breathing as hard. Weightlifting is considered anaerobic exercise—but by making your muscles stronger, it can also help you do better at aerobic forms of exercise.

• When combined with a proper diet, it helps you to lose weight. Each pound of muscle in your body burns up thirty to forty calo- ries a day. The more muscle you have, the more fat you lose. • Weight training is a great way to control stress. It releases “feel- good” chemicals in your body called endorphins, which give you a sense of well-being. • It can make you physically stronger and more capable of safely handling heavy loads. • It will help you perform better in other sports, boosting aerobic fitness and muscular power. MUSCLE DEVELOPMENT Your body has more than six hundred muscles. Each muscle is built up of tiny fibers called myofibrils. When you need to perform a task re- quiring muscle power, your brain sends electrical orders to the muscle fibers through your nerve cells (also called neurons). The muscle fibers

Lifting Weights, Building Strength

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