When Suzy Hamilton runs, when she pushes off from earth with one foot and catches herself two or three yards cross-state with the other, her shoes make a clear snapping sound, as if her soles were popping corn. They aren't. The "crackle" is the earth administering a half-ton of force to her polyurethane soles, an audible "heave" that is equal to but opposite of the "ho" inflicted earthward by the 28-year old's toes. This combined impact/release is the most important moment of the stride — the payoff, when Hamilton is launched as elegantly as an Alvin Ailey dancer mid-gran jet‰. Many biomechanists believe that Hamilton, America's premier 1,000-meter runner and a top miler, too, is a textbook picture of graceful and efficient human locomotion, a high-stepping, arm-swinging epitome of a runner. "People say I run like a gazelle," says Hamilton. "I know that's really corny, but I'm flattered. Have you ever seen a gazelle run?"
Point of accuracy: According to a recent study by comparative biomechanists, the world's "best" runner isn't the gazelle, but its cousin the pronghorn antelope, a three-foot-tall North American that can go 55 and keep it up for half an hour. Sure, the cheetah can smoke its rivals in spurts, but like human sprinters, the big cat can't make it last. That's why middle-distance runners — from 800-meter mavens on up to milers — are, according to U.S.A. Track and Field sports physiologist David Martin, the crˆme of all human "self-locomotors": They go both fast and far. "And isn't that what running is about?" says Hamilton. "Animals go fast to delay being eaten. They go far to stay uneaten."
The human animal generally isn't too concerned about becoming a snack, of course, but anybody can profit from fine-tuning his stride, whether he uses it to log mileage before a 10k, chase down Sparky, or run a buttonhook during a touch football game. As in all human movement — swimming, jumping, throwing — the bottom line in running is efficiency. "The idea is to create long levers," explains the U.S. Olympic Center's Broker, who spends his workweek watching computer-generated stick figures — biomechanical maps of actual elite athletes — bob and weave across his screen. "Long levers can produce higher velocity," Broker continues. "You can try to throw a boulder over the castle wall with your three-foot-long arms — or you can set it on the end of a catapult. Running is the same. You want to recruit as many of the body's strongest muscles as you can."
The first item of business for a runner is the push-off. The gluteus maximus and the quadriceps do the initial work, extending hip and knee and basically catapulting the body forward. The actual boost, however, is provided by the toes. "Think of the toes as an extra gear," says Broker. "When your foot has done all it can, it shifts into overdrive — 'toe' gear." The recovery is next. The "free" leg bends at the knee, making it feel half as long as usual and rendering it less cumbersome to move; then it's swept forward and re-extended out in front, a long lever once again ready for duty. The foot strike completes the sequence.
Hamilton is working with her coach, a German expatriate named Peter Tegen, on a technique that involves taking shorter but faster strides. The theory is that shorter strides result in less deceleration at stride's end. The choppier strides have their pros and cons: Hamilton must take about a hundred additional steps per race to make up for the lost distance, but on the bright
While all this is going on below the waist, up above, the muscles of the back — the latissimus dorsi and serratus posterior inferior — keep Hamilton's torso straight and semirigid, providing a firm chassis on which her legs can pivot. The chest leans slightly out over the legs, sculpting the oncoming wind around her body and shifting her center of gravity a couple of inches forward toward its goal. The arms swing with each push-off — right arm with right leg — sending her center of mass upward a few inches from groin to mid-abdomen. This can make her body feel lighter during push-off, not unlike the sensation on a roller coaster when the car reaches the top of a hill but your stomach keeps going up.
That's the exo-view. Inside, Hamilton's body is pumping out ATP, aka chemical energy, at world-record pace to fuel the muscles. While a sprinter runs almost entirely on stored-up chemical energy, a miler can't do that. All the anaerobic work would leave behind several teaspoonfuls of lactic acid, liquid pain. To be a miler, you have to operate sustainably — at least until the final 150 yards, when you have nothing to lose in letting it rip and going anaerobic. Hamilton's famously "sensible" personality fits this pace. There isn't room in the head of a miler for the neuroses rampant in other disciplines. "The mile is a very sensible distance," Hamilton says. "Everybody can relate to it. You pass mile markers every day."
Of course, you and I can't run like Hamilton and never will. Like all elite athletes, her body is well suited for her sport, and she's good at optimizing its superiorly constructed levers. "She has long, powerful legs, a sturdy torso, a keen sense of balance, a generous assortment of both fast-twitch and slow-twitch muscle fibers, and she's very good at processing oxygen and food into ATP," says Martin. Of course, he's essentially saying she's good because she's good, which isn't the whole story either. If it were, Hamilton wouldn't spend seven days a week fine-tuning her engine. "Ever since I was a little girl, I've known I was good at running," she says. "I've always sensed a sort of effortlessness in my bones, which I don't think every weekend jogger feels. I get this wind-in-the-face sense of joy. I even pretend I'm a horse."
And as it is with all great athletes, past or present: We can stare in disbelief — or try to imitate.
Through trial and error, David Martin says, your body may have already found its most efficient stride. "It automatically gravitates toward the most efficient motion." Still, a quick overhaul of your stride probably couldn't hurt. Here are some tips.
Run more. If you run only once or twice a week, try adding another mile to your route or squeezing in one extra lunch-hour run. The extra miles will strengthen your back muscles, improve your running posture, and help phase out unnecessary and "exuberant" movements. The major muscles will also grow stronger, and each stride will require less energy.
Run faster. Hamilton recommends at least one day a week of speed work. Interval training, such as running eight consecutive 100-yard dashes with 30 seconds of rest in between, is one method. Or vary your normal speed, adding short periods of sprinting and walking.
Practice baby steps. Experiment with a shorter, more powerful stride. Hamilton recommends tying one end of a bungee cord around your waist and the other end around the waist of a training partner. The partner starts sprinting ten seconds before you do; your feet must churn frantically to keep pace. "If you don't take lots of short strides," Hamilton says, "you wind up being dragged through the dirt." The technique can trim ten seconds off your 5k time.
Pull a "sled." You'll need a harness and some weights. Go to the track and, with 20 to 40 pounds tied to the harness, walk stretches of 75 meters. Repeat twice, three times a week, and your torso, hips, and butt will benefit.
Hit the gym. There are two must-do weight exercises for runners. Start with leg extensions, which work the quadriceps. Do three sets of ten with a moderate weight, focusing on the last 15 degrees before full extension. Then flip onto your stomach and do three sets of ten hamstring curls, raising the weight until your lower leg is at a 90-degree angle to the bench. Do both exercises three times a week, increasing the weight by five pounds every third week. Hamilton also suggests some upper-body work, like knocking out 30 push-ups and two sets of 12 pull-ups three times a week.
A) Glutes and quads propel hips and torso forward on push-off. Chest leans out over legs, moving center of gravity toward goal, while arms swing forward. Toes give final boost as the free leg flexes at the knee and is pulled in front of the body.