How to Improve Your Power-to-Weight Ratio

If you're looking for a getaway car, you might think about picking up a motorcycle. They're easier to park, for starters, but they're also much faster. Take a standard six cylinder car for a test drive, and you'll probably be able to top out at no more than 120 miles per hour. Put that engine on a motorcycle, however, and you'll be clocking in at a devil-may-care 300 miles per hour. The motorcycle's advantage is its smaller weight. Rather than hauling around a few thousand pounds of windows, doors and cup holders, a motorcycle is little more than two wheels, some handlebars and a seat. What it all boils down to is more bang for your power buck. Since the engine has less to haul, it can focus more on speeding up.

The same principle applies to athletes. By cutting on down the amount of weight they're carrying, an athlete can increase his or her speed and endurance. The more power an athlete has per pound, the higher the power-to-weight ratio. Generally, athletes measure their power-to-weight ratio by pounds per watt. They take the amount they weigh and divide it by the amount of power they can produce, measured in watts. (Most modern treadmills and exercise bikes come with a function enabling you to measure your watt-output.) Generally, an elite triathlete will produce about 400 to 500 watts -- about half the power needed to run a microwave.

Now, consider two runners: a short, 160-pound runner (let's call him Shorty) who can generate 440 watts of power, and a large, 230-pound runner (let's call him Bruno) who can generate 600 watts of power. Bruno's legs are obviously more powerful, but he would lose a race to Shorty. Bruno has a power-to-weight ratio of 2.6 pounds per watt, while Shorty has a slightly better power-to-weight ratio of 2.75 watts per pound. If Bruno was 218 pounds, then the two runners would be evenly matched. As it is, however, Shorty has the advantage.

For "sedentary" sports such as archery and curling, the power-to-weight ratio is almost irrelevant. But in any sport that involves crossing long distances, it's become gospel truth. Rock climbers will go to great lengths to cut down on the extra weight in their rucksacks -- so you can assume they've given ample thought to slimming down their body weight, too. Rowers are known for their low body fat ratios, and the average professional team will spend tens of thousands of dollars to buy as lightweight a boat as possible. Formula 1 drivers are probably the biggest power-to-weight ratio junkies of anyone. The power-to-weight ratio of a standard Formula 1 car? Four hundred and twenty-two watts per pound [source: Essential Style].

Keep reading to find out how a good power-to-weight ratio can get you airborne.

Most people thought human-powered flight was impossible, so British industrialist Henry Kremer decided to put up 50,000 pounds to prove them wrong. It took almost 20 years, but finally, a 70-pound American aircraft named the Gossamer Condor finally claimed the prize in 1977. At the controls was 24-year-old Bryan Allen. An amateur cyclist and hang-glider pilot, Allen had prepared for five months by putting himself on a strict diet and hitting the gym regularly. The results were spectacular: He lost 15 pounds without sacrificing any of his pedaling power [source: Wahl]. On race day, at a lean 6 feet and 145 pounds, Allen piloted the Gossamer Condor around the mile-long course to victory. It was a triumph for aviation -- but also for the power-to-weight ratio.

Just as you need a good power-to-weight ratio to fly a human-powered aircraft, so too do you need it to reach the pinnacle of endurance sport. In any triathlon, serious contenders have to show up with bodies that are a near-perfect balance of strength and weight. There's not an Ironman winner on the planet who hasn't spent days and weeks agonizing over his or her personal "ratio."

For running, every extra pound can cost about two seconds a mile [source: Friel].

Over an entire marathon, that means a loss of almost half a minute. Which, if you're running in a world class event like the New York City Marathon, could mean the difference between first and fifth place.

For cyclists, hill climbs will be the ultimate proving ground for your power-to-weight ratio. If your ratio is poor, you may be able to keep to the front of a pack using your wits alone. But once it comes down to pumping your way up a steep grade, you'll start to notice the difference. A classic example is that of 1996 Tour de France winner Bjarne Riis. Years before, Riis had been little more than an underdog rider. But thanks to a strict coaching regimen, Riis was able to drop 15 pounds while also ramping up his pedaling power. By the time the Tour started, he had miraculously achieved the ideal ratio of 3 watts per pound.

Riis was up against Spaniard Miguel Indurain, who was fighting for his sixth consecutive Tour de France win. Indurain was much more powerful than Riis; when pedalling all-out, he could generate 550 watts [source: Kessler]. Riis could only manage 480 watts, but he was a full 26 pounds lighter than Indurain. In the end, Riis' power-to-weight ratio was only fractionally better, but it was enough to put him ahead of Indurain and into the lead [source: Kessler].

Generally, in cycling, the ideal hill climber will weigh about two pounds for every inch of body height [source: Hughes]. If you're 5 feet 9 inches (the average height for a U.S. man), that means you should be tipping the scales at 154 pounds.

Unless you happen to be packing a spare tire around your midsection, improving your power-to-weight ratio is no easy task. If you're an elite triathlete, your body is already low in excess fat and in peak condition. But by using a combination of diet and exercise (mostly diet), you can transform it into a different kind of peak condition that's more suitable to your racing needs.

When describing a top athlete, many will use the expression, "There's not an ounce of fat on him." It's flattering, but the truth is that there are many ounces of fat on the athlete -- ounces of fat that he desperately needs to perform. The average human body needs a minimum of 2 to 13 per cent body fat in order to maintain healthy skin and hair and insulate the body against harmful substances [source: American Council on Exercise]. For triathletes, that number goes up. The ideal body fat percentage for elite triathletes is about 5 to 10 per cent for men and 10 to 15 per cent for females [source: Garand]. When shedding pounds, make sure you do it without compromising a healthy body fat percentage.

A fad or miracle diet may be tempting, but by far the most effective way to diet is to count your calorie intake. Start by sitting down to do some math on how many calories you burn during the course of one day. It might help if you use an online calorie calculator such as this one [source: Health Status]. If you burn 3,000 calories a day, simply structure your diet so you only take in 2,800.

Fresh fruits and vegetables are your secret weapon: They're low in calories, but they'll fill you up. Also, keep a handle on what fluids you're taking in. Although it doesn't feel like much, liquids like juice, beer and milk are deceivingly packed with calories. You'll also want to stick to a strict meal schedule. Skipping breakfast, for instance, can cause you to overeat at lunch. Ideally, you might consider keeping yourself fueled by "grazing" on a series of healthy snacks throughout the day. Always have food at hand.

As an athlete in training, exercise is already something that you do regularly. Unfortunately, you probably won't be able to achieve an ideal race weight without a fair dose of suffering in the gym. Moderate exercise is good at building endurance, but it won't help you increase your power as effectively. To do that you're going to need brutal, high-intensity exercise: All-out sprints and exhausting weight reps at the gym. These exercises don't need to last long, but they should become a regular part of your workout [source: RacingWeight.com].

Weight loss is a slow process for triathletes. Per week, the most you can hope to lose is about a pound (450 grams) per week [source: Triathlete's World]. Any more, and you can compromise your overall strength. What's worse is that you could also weaken your immune system. Nothing will throw off your race time worse than a poorly timed cold or flu.

Of course, your body isn't the only thing that needs slimming down. That thick, lustrous head of hair? That solid-gold good luck charm? Your 1967 vintage racing bike? These all represent extra weight that can slow you down during a race. Before every triathlon, take a close look at your clothing and equipment to see if there's anything you can ditch or trim to save weight. Currently, the world's lightest road bike is around 7 pounds (about the weight of a house cat) -- but that's going to set you back more than $15,000 [source: VeloNews].

For lots more information on training, see the links on the next page.