Muscle on the Move
SUPER ATHLETE: SUSIE MARONEY
Claim to fame:
In 24 1/2 hours, this 24-year-old Australian swam 172 km (107 mi) from Cuba to Florida. Fifty people failed at the same swim before Susie Maroney made it in 1997.
Susie swam in a shark cage pulled by a boat — a move that saved her life. (You can see the cage at the top of the photo.) A 3m (10ft) hammerhead shark trailed her, and other sharks battered the metal cage! Jellyfish slipped inside and dotted her body with stings. Her only rest: Every hour, Susie treaded water while she drank sports drinks and ate yogurt and bananas.
Susie has asthma (AZ-muh), a disease that can make it hard to breathe. To strengthen her lungs, she learned to swim at age 3.
Susie builds strength and stamina (see vocabulary list) by swimming 6 hours a day, 6 days a week. That builds long distance strength in many muscles — including Susie's heart!
A stronger heart can pump more blood. As blood circulates (moves in a loop), it picks up oxygen gas from the lungs and nutrients from food. To keep going, muscles need to soak up oxygen and nutrients from the blood.
SUPER ATHLETE: TINA BESSINGER
Claim to fame:
Tina Bessinger's awesome tricks won this 22-year-old superstar the national wakeboarding championship in 1997.
This extreme sport is a cross between snowboarding and water-skiing. Tina slips her feet into boots that are attached to the wakeboard, and grips a rope that's attached to a moving boat.
To do tricks, Tina steers toward the wake — the v-shaped wave that the boat creates. Like a ski jump, the wake sends Tina flying into a flip, a spin, or another trick.
"Even basic tricks are fun!" says Tina.
Every time you move a muscle, it contracts (shrinks and tightens). Exercise makes muscles contract hard, over and over. These contractions make muscles bigger, stronger, and able to work longer without getting tired.
Tina controls her moves by pulling the rope. So, besides practicing her moves on the board twice a day, Tina lifts weights to build arm, shoulder, and back strength. She also gets 8 hours of sleep a night and eats plenty of low-fat, nutritious food. "No fast food!" she says.
SUPER ATHLETE: RICKY WILLIAMS
Claim to fame:
This 22-year-old running back is famous for catching "un-catchable" passes. He won the Heisman Trophy for the best college player in 1998 and signed a multimillion-dollar contract with the New Orleans Saints.
Ricky has 102 kg (225 lb) of power — but the wall of defenders waiting to tackle him has even more. Running sprints (short races) builds muscles that give Ricky quick bursts of power.
Ricky also needs agility to weave around his beefy opponents. For every weave, Ricky's nervous system sends a message to all the muscles that need to move. The more Ricky practices, the faster his nervous system can jolt the muscles into action.
Coordination, such as the ability to leap up and grab a hurtling football also demands split-second communication between Ricky's muscles and nervous system. The more Ricky practices, the easier it gets.
Quick, stop your heart for a second. You can't do it, can you? Your heart is made of cardiac (CAR-dee-ak) muscle-a kind of muscle that works automatically and never gets tired.
Your heart is about as big as your fist. But exercise will make it bigger so it can pump more blood.
MUSCLE AND BONES
Without bones, your flesh, organs, and skin would fall to the ground like jelly. But with no muscles, you would stand still as a statue.
Tendons attach skeletal muscles to bones. Contracted muscles pull on tendons, tendons pull on bones, and you run and jump!
You can feel your Achilles' (uh-KIL-ez) tendon-the band at the back of your ankle. It connects your calf muscle to your heel bone.
Read On! Check your library or bookstore for this fabulous, fact-filled book: Professor Protein's Fitness, Health, Hygiene and Relaxation Tonic, by Steve Parker. (ISBN 0-76130494-0)Article Vocabulary:
agility-ability to move quickly and easily
cardiac muscle-the muscle that forms your heart
nervous system-your brain and nerves; carries messages around your body
nutrients-chemicals in your food that your body needs to live and grow
skeletal muscles-muscles that move your skeleton
tendon-tough bands that connect muscles to bones