Building tri-specific power on the bike
By Matt Fitzgerald
May 28, 2008 -- Power seems so straightforward. It boils down to a single number that you read on your bike’s power-meter display (assuming you have one). But power, as it relates to triathlon cycling performance, is somewhat more complex, and, regardless of whether you train with a power meter, you can boost your performance by including power-related training sessions.
There are three distinct ways to increase power output on the bike: you can push bigger gears, you can increase your cadence and you can climb. The ability to push huge gears comes from pure muscle strength, but this is only part of the power equation. Your pedaling power is greatest when you’re strong at high muscle-contraction speeds, such as at 90 RPM or greater (those who are strong at slower muscle-contraction speeds are better suited to towing fire trucks). In fact, increasing your cadence at any given gear ratio always increases power output, but this is beneficial only if your neuromuscular efficiency at the higher cadence is equal or greater (and there is no one-size-fits-all when it comes to optimal cycling cadence). Finally, climbing performance is affected by rider weight. On a flat road, the cyclist who’s putting out the most power is the cyclist who’s moving the fastest (assuming equal aerodynamics). But on climbs, it’s the rider with the highest power-to-weight ratio that gets to the summit quickest. So there’s no simple answer when it comes to building optimal power for triathlon.
Doing it rightIncreasing your maximum power output on the bike is unlikely to improve your triathlon cycling performance and may even worsen it. The physiological underpinnings of maximum and sustained power become mutually exclusive after a certain point. Thus, the way to improve your triathlon cycling performance is to increase the percentage of your current maximum power output that you can sustain over the race duration.
Given these complexities, what place, if any, should training at maximum or near maximum power output have in your training? The answer is that you definitely should do a small amount of bike training at the upper end of your power range, because this type of training carries three important benefits. First, it minimizes the amount of power you lose over the course of a training cycle. It is normal for individual muscle fibers to become slightly less powerful through endurance training; however, because their cross-sectional area decreases even more, their power-to-size ratio actually improves. Doing a little maximum-power training on top of a lot of aerobic training will boost your muscle fibers’ power-to-size ratio further.
A second benefit of maximum-power training is that it activates more muscle motor units than lower-intensity training. Again, when a small amount of maximum power is layered on top of a lot of aerobic training, the effect is that your neuromuscular system learns how to make more total muscle tissue contribute cooperatively to performance at race intensity.
Finally, maximum-power training, especially when done relatively early in the training cycle, is an efficient way to prepare your body to safely handle a higher training workload in the mid- to late season. Small doses of very high intensity work are relatively well tolerated, even at a very modest level of base fitness, but they stimulate adaptations (such as a surge in aerobic capacity and better resistance to muscle tissue damage) that quickly enable the body to successfully absorb much larger doses of submaximal exercise.
Boosting max powerTraining at your maximum power output level is a fairly simple matter. It requires that you turn the cranks as fast as you possibly can against heavy resistance for no more than 20 seconds at a time. The heavy resistance can come from a hard gear or a steep hill.
In the early base phase of training (or if you have returned to a short late-season base phase before beginning your final build of the year), throw a smattering of power intervals into one or two endurance rides each week. It’s good to do a mix of high-gear power intervals on flat terrain (or a trainer) and power hill intervals, as each type stimulates slightly different adaptations in the body.
In the mid- to late base phase, complete one power-interval workout each week. For example, warm up with 20 minutes of aerobic riding then ride 10 x 20 seconds up a steep hill at maximum effort (out of the saddle), spinning for 2 minutes after each climb and finally cooling down with another 20 minutes of aerobic riding.
Start with a manageable number of intervals in the first week and add intervals during each subsequent week (except recovery weeks) for the next four to six weeks. You will then find your body ready to handle and perform well in other, more challenging, types of high-intensity workouts in the build phase.
Throughout the build and peak phases of training, go back to a smattering of power intervals in an endurance ride once a week to maintain the adaptations you earned in the late base phase. That’s all you need to do to enjoy the triathlon-specific fitness benefits that you can only get from churning out the largest wattage number you possibly can.