Just as training methods changed with the advent of portable heart rate monitors, power meters are pushing the theories and methodology of endurance training into new territory. The biofeedback that power meters provide brings amazing clarity to training, if the information is interpreted well.
Speed, perceived effort, and heart rate are very useful for gaining insight into a person?s training, but variables associated with those measures lead to ambiguous results.
Power is a more concrete, objective way of looking at a person?s training. More specifically, the amount of power an athlete produces at given heart rates provides a very clear picture of his or her current state of fitness. Just like heart rate values, power outputs cannot be compared between individuals but can be effectively used to chart one?s own progress. And progress is the desired end result of any training program.
Power equates to the amount of work you produce in a given period of time. Riding a bicycle up a specific hill always requires the same amount of total work. When you produce that work at a faster rate, you are producing more power. Conversely, a rider producing more power over a given distance will cover that distance at a faster rate.
Current bicycle-mounted power meters measure the strain a rider puts on the crank or rear wheel and translates that into watts. Watching your wattage during the course of a ride is not very useful. Wattage fluctuates quickly and often; heart rate is a much better gauge of workload during a workout.
Power becomes useful when you are sitting in your living room after the workout. I recommend purchasing a power meter that can be downloaded to your home computer. Downloadable power meters help you see how your power output changes with your heart rate, speed, and cadence during the course of a single ride, a few weeks, or several months. I started working with two-time Ironman Hawaii World Champion Peter Reid in June of 2000 with the goal of improving his performance on the bike leg. He started working with a power meter so I could get more precise information on his training.
We started loading his training program with long intervals near his lactate threshold heart rate to increase the amount of power he could produce for sustained periods of time. During the rides, Peter concentrated on keeping his heart rate and cadence within specified ranges; I did not want him to consciously try keeping his wattage constant.
After a few weeks, I compared the computer files from those workouts and was pleased to see the results I expected. His heart rate and cadence ranges remained generally constant, but his average power output for 20-minute efforts increased by over 9%. When dealing with world-class athletes, 9% is an astronomical increase in performance. A few weeks later, Peter won Ironman Canada, an important event in his preparation for the Ironman Hawaii, which he also won.
Increasing sustainable power output at lactate threshold is very important for improving time trial performance.
The intensity level for these workouts is critical. They must be done very close to an athlete?s lactate threshold heart rate, but not above that heart rate. You want to ride at the highest sustainable workload possible without accumulating lactic acid, which will force you to slow down.
One way to keep the intensity high enough without overloading the muscles is to keep the cadence for lactate threshold workouts above 90 rpm. The higher cadence shifts some of the stress of the effort from the legs to the cardiovascular system. A highly aerobic engine can handle the extra stress better than the muscles can because accumulated lactic acid is more detrimental to performance than breathing faster.
Power meters are like any other piece of training equipment: The information you gather can be useful or useless, depending on what you do with it.
Power outputs start falling when athletes get tired, useful information for short-burst on-the-bike resistance workouts where a heart rate monitor is generally irrelevant.
However, when you use a power meter, you can view the power output of each interval during the rest periods between them. When power output starts falling rapidly during successive intervals, it is time to stop and go home; you?re too tired to put forth a full effort and are therefore just wasting energy.
Information is power and right now power is the newest form of information. Advances in technology have moved power monitoring from the lab to the road, track, and trail. What was previously only available to world-class athletes is now available to anyone interested in efficiently improving his or her fitness and performance. Use it wisely.