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" Nurturing Nature: The Perfect Athlete Much has been written about the superhuman athletic ability of swimmer Michael Phelps, winner of six gold medals at the 2004 Athens games. He&amp;#039;s a genetic phenom, built like a fish, with hands and feet like canoe paddles. All this is true--it is impossible to win at the Olympics without a genetic predisposition to your sport. But if Phelps accomplishes his goal of breaking the record of seven gold medals in one Olympics, set by Mark Spitz in 1972, it will be the result of a perfect blend of natural ability, training and technique. Marathoner vs. Sprinter: How Muscles Translate to Speed  (Ryan Hall photograph by Victah Sailor, Tyson Gay photograph by Getty Images) The Giant Swing, Step-by-Step When Team USA&amp;#039;s Nastia Liukin makes the grand, sweeping arcs of the giant swing, it may look like a simple series of circles. But there is a complex interchange of force and energy between the gymnast and the flexible bar she&amp;#039;s holding onto. The giant swing must be both artful and functional--a gymnast must maintain good form, keeping her arms straight and toes pointed, while building up enough momentum to launch into a double-somersault dismount. With great strength and incredible timing, she gracefully defies gravity.  The Speed of Spheres  How fast does your favorite Olympic orb travel? Here&amp;#039;s the ultimate ball-by-ball breakdown.   *Objects to scale. (Photographs by Getty Images) Raising the Bar  The world record for pole vaulting, 20 ft. 1.75 in., set by Ukrainian Sergei Bubka, has stood for 14 years. American Olympic hopeful Brad Walker holds the U.S. record of 19 ft. 9.75 in. What would it take to get over that extra 4 in? The secret to high vaults is 85 percent physics, 15 percent acrobatics. To build up enough kinetic energy to lift himself within striking distance, the 6-ft. 2-in. Walker needs to run at least 33 ft./sec. When the pole is planted, it acts as a spring to transfer Walker&amp;#039;s energy (4195 joules) from the horizontal plane to the vertical, lifting him 16.7 ft. high. The additional 3.4 ft. comes by bending his body and pushing his center of gravity up and over the bar.    The Hydration Race  (Photograph by Getty Images)  An Olympic athlete consumes as much as 3 gal. of water per day during competition (that&amp;#039;s 5.5 times the suggested intake for a typical person). Competitors will have to drink more in Beijing, where August temperatures exceed 85 F and humidity hits 90 percent. Losing just 2 percent of body fluids (that&amp;#039;s about 3.5 pounds or 2 quarts in a 180-pound athlete) is enough to cause a dip in performance. &amp;quot;When you lose water, your blood gets thicker and your heart has to work harder to pump it,&amp;quot; explains sports nutritionist Nancy Clark. Knowing sweat rates allows an athlete to properly rehydrate to prepare for the next round or match.  Launching Into a Dive  (Photograph by Getty Images)  Olympic divers dazzle with their acrobatics in the air, but it&amp;#039;s the launch off the board that spells the difference between a medal-winning dive and a splashy failure.   Cheating an Upstream Gate  Kayaking the rapids of Shunyi Olympic Rowing-Canoeing Park in Beijing will take &amp;quot;strength, balance and focus,&amp;quot; says three-time Olympian Scott Shipley. Competitors must navigate 18 to 25 gates suspended above water flowing at about 15 ft./sec. The toughest part of the race is an upstream gate, where reversing currents can turn a small mistake into a race-ending rollover.    1. The kayaker sideslips downstream toward the gate. As the boat passes under the poles and into the eddy, the paddler plants his blade to swing the stern around.   2. Since only the racer&amp;#039;s head needs to pass through the gate, most competitors slide, or cheat, their boats under the interior pole and then swivel their torsos around it. If the kayaker&amp;#039;s angle on the turn is off by a fraction of a degree, the downstream current will capsize the boat. If done properly, the paddler pulls 1.5 g&amp;#039;s during the turn.   3. The kayaker rides the upstream eddy current, which flows at 9 ft./sec. on the Beijing course. As soon as the paddler clears the gate, he leans back, submerging the stern, and elevates the bow, which shortens the boat&amp;#039;s turning radius from 11.5 ft. to about 5 ft.   4. To re-enter the downstream current, the kayaker plants his paddle, generating 65 lb.-ft. of torque, and heads to the next gate. The entire maneuver takes 3.5 sec. "^^<http://www.w3.org/2001/XMLSchema#string>
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