Training using a power meter to get the best out of your training ride is increasingly popular. Power meters generally come with a handlebar mounted computer (such as a Garmin Edge GPS) that displays information about the power output generated by the rider such as instantaneous, max and average power. Strada build wheels using the hub based system called the PowerTap. It uses a torque strain gauge inside the rear hub to measure the rider’s power applied through the each pedal stroke. The Powertap is a cost effective and convenient way to measure your power and can also serve as an all-around cycling computer to display heart rate as well as riding speed, distance and time.
Power meters provide an objective measurement of real output that allows training progress to be tracked very simply—something that is more difficult when using, for example, a heart rate monitor alone. Cyclists will often train at different intensities depending on the adaptations they are seeking. A common practice is to use different intensity zones. When training with power, these zones are usually calculated from the power output corresponding to the so called lactate threshold or MAP (maximal aerobic power). Power meters provide instant feedback to the rider about their performance and measure their actual output; heart rate monitors measure the physiological effect of effort and therefore ramp up more slowly. Thus, a cyclist performing “interval” training while using a power meter can instantly see that they are producing 300 watts, for example, instead of waiting for their heart rate to climb to a certain point.
In addition, power meters measure the force that moves the bike forward multiplied by the velocity, which is the desired goal. This has two significant advantages over heart rate monitors: 1. An athlete’s heart rate may remain constant over the training period, yet their power output is declining, which they cannot detect with a heart rate monitor; 2. While an athlete who is not rested or not feeling entirely well may train at their normal heart rate, they are unlikely to be producing their normal power—a heart rate monitor will not reveal this, but a power meter will. Finally, power meters enable riders to experiment with cadence and evaluate its effect relative to speed and heart rate. Power, in cycling terms, is calculated by dividing work by time and is represented in Watts. Why is measuring your output important? If you continually spend too much time above your optimum level you will over train. If you spend too much time at low intensity you will not gain the fitness improvement you want to achieve. A Powertap hub will provide a easy to measure benchmark to monitor your current fitness level and improvements each month at different levels of intensity. It can then be used to highlight improvements and areas needing attention. Tom will be writing a series of articles to document his experience of training over the winter with a Powertap wheelset and Apollo Raceday software from PhysFarm. You can read the first in his series of Powertap training articles by following the links. You can see Powertap wheels in the Strada shop.