Saturday, April 27, 2013

Why the Fastest Tri Might Not Be the Most Aero

Aerodynamics. We've all heard endlessly about it. It matters, a lot. After you hit the magical number 16 (mph, the speed at which the wind really starts demanding most of your energy), aerodynamics are the key to riding fast. In fact, research suggests that unless there are courses with extended climbs of over 7% gradient, that it's fastest to ride with a disc wheel, contrary to some athletes I know that will put on the climbing set at the first sign of anything but flat. Over 80% (some studies suggest) of an athlete's expended energy is going towards fighting the wind. Over an Iron-distance triathlon, things like an aero-bar mounted water bottle will save around 5 minutes over a bottle mounted on the down tube.

But, contrary to popular belief, the fastest set up on the bike may not be the fastest. Why? Because a triathlon isn't a cycling time trial, there are three disciplines to complete. And with a run after the bike there are certain things to think about. Look at a pro cyclist. The seat height to bar height sports a ridiculous drop. As BMC rider Taylor Phinney puts it: "Time trialing is all about putting yourself in an uncomfortable position for around an hour." The massive difference between saddle and bar height on a TT bike makes it easy to get a flat back, while maintaining a flat chest that is parallel to the ground, and easier to get the head lower. The goal of a TT specialist like Phinney is to get the shoulder and the hips nearly parallel with the ground, and level with each other. Draw a straight line from his hips to his shoulders and the angle will be less than 5%. But the strain on the back that a position like that puts on the body makes for a slower run in a triathlon, because the lower back will be tight, not supple like we want it.

In addition, most triathlons are at the maximum distance of a cycling TT. An Olympic distance, 24.5 mi ride is usually the longest you'll ever see a TT. And obviously, that means that the half and full Ironman cycle legs are far longer than most pure cyclists see while on a TT bike. Chris "Macca" McCormack put it best when he said, "The fastest position is the one you can hold for three hours."

Another example to draw on is the hip angle. The women in Kona have consistently run faster marathons, dropping course records in the marathon nearly every year. When analyzed, the hip angle of the women is also consistently more open. They don't have quite as aerodynamic position on the bike as the men like Sebastian Kienle, but comparatively, they run faster.

The triathlon is a unique combination of three of the most difficult sports to compete in individually. The bottom line here is that to compete well in triathlon, there is a consistent give and take. Individuals can be great swimmers, cyclists, and runners, but at the end of the day, it's about who can put all three together.

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