Wednesday, December 22

Cycling 101: The Time Trial

Cycling is a fringe sport in the States. It's also my sport, and as spring rolls around, and I'm racing two or three times a week, I'll be blogging about it more often. In the winter, I thought I'd write a few background posts for those gentle readers who might want to more about the ins-and-outs of racing bicycles. Today, I'm going to talk about the race of truth, the time trial.In an individual time trial, riders start at 30 second to 2 minute intervals. If a rider is passed, the passing rider is required to pass wide of the other rider and both riders must avoid any drafting. Drafting, if you recall from my earlier posts can reduce power expenditure at a given speed up to 30% over not drafting. Since there is no drafting, therefore no tactics, the race is just man and machine against the course and the wind, the time trial is often called, "the race of truth". Regionally, time trials are often done on the same course as previous years (or earlier in the season). Many time trialists race their last time on that course as much as the other riders.

Time trial bikes are specialized beasts because in a time trial, aerodynamics rule. There is no drafting, and no pack, just the wind. Aerodynamic drag scales with the square of the speed. So a small increase in speed, means a larger increase in drag. Mechanically, bikes are incredibly efficient. It's the wind that slows them down. A time trial bike looks something like this: . Mine is quite similar. Time trial riders wear aerodynamic helmets, skin suits, and ride those funky bikes to get down low and be as aerodynamic as possible. The first few times riding on aero-handlebars you feel like a weeble, wobbling but (hopefully) not falling down. After just a few hundred miles of training, it becomes more of a second nature.

After that is done, what follows next? Well the name of the game is measured effort. You want to finish the race completely exhausted, every last ounce of energy spent on the course. But, if you go out too hard, you "blow up" and have to slow to recover (and never do recover quite as well). This loses time from the ideal case. Of course, if you finish having gone a little slower than your best effort, you didn't finish ideally. How is effort measured. Well, heart rate monitors (HRM) are common. These are chest strap transmitters and a little receiver/computer which acts as a portable EKG. With constant feedback on heart rate, a rider (in his training) learn where his threshold lies. By threshold, I mean that point in effort where you start burning more oxygen than you can take in. Above that threshold you are on borrowed time, that pace is not sustainable. Keep going that fast, and you will blow up. Getting more and more common these days are strain-gauge based power meters. These devices either installed in the crank, bottom bracket, or rear hub directly measure your pedaling force. This can be directly converted to power. Power output is believed to be a better measurement, which is also then used to find your threshold. Finally, besides the HRM and the powermeters, you learn by experience how to gauge your effort. What it feels like when you are riding right at the edge of your threshold.

Ultimately what this all comes down to, is being able to gauge your effort and then (always the kicker) going out and doing it. By that, you set yourself to putting out that effort and sustaining through the entire ride. After the first few minutes, concentration is crucial. If your mind wanders from the task of carefully monitoring that effort, trying to optimize your form and gearing, then you immediately slow down. I am always surprised at how quickly, the speed starts drifting down as soon as attention wanders. But with practice, like everything else the human animal attempts, improvement comes. There is a certain amount of, uhm, discomfort associated with pushing your body to its limits. But, in the heat of the race and the desire to keep your speed up, you don't concentrate on that, and mostly recall how painful it was after the ride is over.

I hadn't done time trials very much for a few years after I started mass start races (criterium's and road races) but last year, I got a great deal on a bike like the one pictured above. As a result, I entered in a half dozen time trials last year and am looking forward to them again this year. Time trials are a great way for the novice to get started. To measure your fitness and remember, in the end, in a time trial you are mostly racing against yourself and your previous performances.