Where Is the Power in a Cycling Power Meter? 
This article is to give you “The Power” that can be found within a cycling power meter. Whether we use a power meter or not in our cycling we can learn a lot about what the data tells us. To focus on the data itself is the error; the data is simply a reflection of you and the sum of your performance / fitness variables for that effort or training session. The key is to understand why your power outputs are up or down, what factors affect it and how the relationship of power to heart rate is crucial to understanding. Read on to get your golden keys to understanding where the true power is…. First of all it is important to note that any power data is irrelevant without duration and longer duration aerobic energy system efforts are better understood when considered with heart rate. After all: power = energy / time or watts = joules / second What this means is it is not just how much power or energy we can produce but it is over what duration. A great example is the track running 100m dash. The runner who wins is able to expend the most relative energy (to size / drag and mass) over that duration. This lends the ultimate hint to where the power is. Our performance can boil down to one concept, vitality and training stimulus. We see that when we are fit if we wake up race day sick or fatigued we flounder. That said when we are vital and healthy and rested but haven’t done adequate training work, we also flounder. The key to excellence in performance and improving is in staying vital, healthy and consistent in the required training efforts over long enough duration (years) to stack up the gains. Where our heart rate comes into play is that while we gauge our anaerobic or sub 1 minute power outputs in terms of peak and average wattage. We can measure our relative aerobic power at lower endurance heart rates and extrapolate our sustained maximum efforts at threshold for a given duration. Let us say that we do a 30 minute time trial test at 185hr (heart rate) and the result is 320w average. During the warm up of this test we did an endurance power to heart rate test at 145hr and we produced 240w average. There is a relationship in the aerobic engine at power to heart rate intersects. Thus as we increase power at 145hr our power and performance also increases at 185hr. Now there are more details involved with what this relationship is and how best to train the aerobic system but the fact is you can test your fitness without doing an all-out time trial effort each week. It is important to note that power meter calibration, athlete hydration, fatigue, health, altitude, temperature all affect our power outputs. This is where we learn from the power data on how we gain, lose and manage our performance. So the challenge here is not to get trapped by the ticking by of power numbers as we train, it is best to cover or flip that display as the treasure found from power data is not in the numbers but how you get them and what they tells us as athletes.