A power meter measures the power applied to the paddle by the athlete. By doing this, the power value represents the work (energy output) rate of the paddler (Watts), and provides a direct measure of the athlete's intensity.
Understanding that the power value is measured in this way is important: The power value includes both the productive and unproductive power generated in a single value. In other words, not all of the power applied to the paddle will result in forward propulsion of the boat. A higher power value does not guarantee increased boat speed.
The primary use of a power meter, in a sporting application, is to measure the intensity of the athlete, in this case, the rate of energy production of the paddler. This direct measure of intensity is important for setting training levels, tracking fitness development, improving efficiency and race planning. Refer to the other sections of this guide for further explanation of these uses.
The power value shown in real time represents the average power generated during the entire stroke, not just the drive phase of the stroke. This includes the glide phase, where the paddle isn't in the water. The stroke is defined as the event that occurs between the blade exiting the water (stroke = glide phase + drive phase). It is important that the glide phase is taken into account when calculating the power value. The power value is a measure of intensity (energy output per second) and the glide time contributes to the overall level of intensity. For example, paddling with a long glide (paddle is out of the water for a long duration) requires less intensity than paddling with a shorter glide time.