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Becoming a Champion

Are Athletes Born or Made?

There's a joke in sports that says, “You need to pick your parents wisely.” That's because, to a great degree, you inherit your athletic ability. Body type often influences which sport best suits an athlete and how successful he or she will be. Long “gorilla arms” and big “paddle” hands help swimmers pull themselves through the water. A small, light body (5 feet 4 inches/110 pounds) is a plus for a jockey who sits astride a racehorse, but not for a basketball player whose fellow National Basketball Association (NBA) players average 6 feet 7 inches and weigh 225 pounds.

Nature can also stack the deck for athletes in ways that can't be seen. Genes that you inherit determine the make-up of your skeletal muscles—the kind involved in movement. That can give an athlete a natural advantage in certain sports or activities.

Which Twitch Is Which?

There are two main types of skeletal muscle fibers—fast-twitch and slow-twitch. Everybody has both kinds, but the amount of each can vary widely. It's something you're born with that really can't be changed.

All muscles work by contracting. Fast-twitch muscle fibers contract quickly but fatigue, or tire, easily. You use them when you need quick bursts of energy. People with a high percentage of fast-twitch muscle fibers might excel as shot-putters, weight-lifters, and sprinters.

For high-endurance activities, you call your body's slow-twitch muscle fibers into action. These fibers produce a steady supply of energy for activities that last longer than a few minutes. For marathon runners, cross-country skiers, and long-distance cyclists, a high percentage of slow-twitch fibers is an advantage.

Who's the Boss?

Genes provide the blueprint for your body. They influence the way your body looks on the outside and the way it works on the inside. But sometimes—like 5-foot-3-inch Tyrone “Muggsy” Bogues, the smallest player ever in the NBA—you can say to your genes “Hey, you're not the boss of me!”

One way to do that—and a key to peak performance—is training. Most elite athletes train to improve both overall fitness (strength, flexibility, speed, and endurance) as well as sport-specific skills.

How Fitness Training Works

Athletes lift weights to improve muscle strength and power. Muscles can double or even triple in size with exercise, but training doesn't make new muscle fibers. Instead, it increases the size of the muscle fibers that are already there, filling the cells with a protein that makes muscles contract more powerfully.

Exercise causes microscopic tears in the muscles. This is why you feel sore the day after you exercise. But as the tears heal, the “protein-making machinery” in the muscle fiber is turned on to rebuild—and strengthen—muscles.

Muscles “damaged” by exercise become a bit shorter, like a cord that's been cut then sewn together. Stretching helps restore a muscle's length and improves an athlete's flexibility. Increased flexibility reduces injury and improves performance. Flexibility can give a swimmer a longer stroke. The longer the stroke, the faster a swimmer can move through the water.

Endurance training—swimming, cycling, rowing, and jogging long distances—helps athletes perform at a faster pace while using less energy. The bodies of well-trained athletes become better at getting oxygen to their working muscles. Their lungs take in more air. Their hearts get bigger and stronger, pumping out more oxygen-rich blood with every beat.

Feel the Burn

If you eat turkey at Thanksgiving, you gobble up fast-twitch (white meat) and slow-twitch (dark meat) muscle fibers.

You can't see your fast-twitch and slow-twitch muscle fibers, or determine what proportion you have of each, without having a doctor remove a muscle sample from your body and examine it under a powerful microscope. But you can feel the presence of fast-twitch muscles.

  • Rest your back against a wall, standing with your feet slightly apart about six inches from the wall.
  • Slowly slide down the wall, bending your knees, until you're nearly in a sitting position.
  • See how long you can hold that position. The buildup of lactic acid causes the achy feeling in hard-working fast-twitch muscles in your thighs. In that position, blood circulation to your thigh muscles decreases so lactic acid isn't removed quickly from those cells.
  • Stand up and walk around. Does the achy feeling go away as the blood flow to your thighs returns to normal and your muscles relax?

Easier Done Than Said

What goes on inside your muscles when you raise your hand in class to answer a question? It's complicated.

A muscle is a bundle of very long cells called fibers that stretch all the way from one end of the muscle to the other. These fibers have inner strands called myofibrils which are made up of tiny threads of protein that hook together and slide over each other to make the muscles contract. When the right muscles contract, your arm goes up. Whew!


  • gene: A tiny part of a plant or animal cell that determines a characteristic that will be passed on to the plant's or animal's offspring.

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  1. What are some of the traits mentioned in this article that are passed along from a parent to a child?
    [anno: Answers could include athletic ability, body type, kinds of skeletal muscles.]
  2. What are some of the traits mentioned in this article that a person might develop on his or her own?
    [anno: Answers could include overall fitness, muscle size and strength, flexibility, speed, and endurance.]
  3. Think of your favorite physical activity. Does this activity involve short time periods of high-energy activity? Does the activity involve energy being used over a long period of time? Do you think you use more fast-twitch or slow-twitch muscle for this activity?
    [anno: Answers will vary.]