What is Power and Normalized Power?
So, what exactly is Power?
I originally got a power meter as everyone had one.
Beyond knowing that Power is the rate at which energy is used (energy over time) and is measured in watts, at the time I had no idea what to do with it; but, thought it was an interesting data point that at some time I would know how to leverage.
In simple terms, when you are biking, you are essentially a turbine creating power that is pushing the forward. The more power you generate, the faster you go.
If you were to hook your trainer up to your electrical system, you could power your home while you cycle, so far as you can generate enough consistent power. So, when a Sprinter in the Tour de France, generates 2K watts in a sprint, he essentially can power two houses at normal consumption level for a very short period of time. Another comparison: One horsepower is equal to about 750 watts.
Watts matter. The challenge is always around how many watts, on average, can you generate over time. It is not about staring at your bike computer while racing the whole time; but, it is useful for seeing how much power you are maintaining (or not maintaining); and, when climbing, to be sure you are not blowing yourself up. More than anything, it is an extremely useful tool for targeted trainer efforts.
In short, if you can generate about 250 watts over the course of a FLAT Half-IronMan course you will finish the ride in 2:40. It's that simple. On a flat course, it doesn't matter what you weigh, it is all about raw power. Therefore, big, strong dudes like flat courses and skinnier folks like hills. Throw in temperature, wind, turns, elevation, etc... and it creates the challenge that you solve through, what I have referred to as, "Course Management".
Power is measured through two things; how hard you are pushing your pedals on the downstroke and your cadence. Think of it this way. When you are climbing a hill, you can, in an effort to maintain a certain level of power outage (which is generating your speed up a hill), either mash your pedals as hard as you can or increase cadence. Through both, you will tire out, but differently. This is where watts per kg matter. Physics, a 150 pound guy pushing 300 watts up a hill will go faster than a 200 pound guy pushing the same 300 watts. That is why I am always harping on weight loss.
Functional Threshold Power (FTP) is simply how much Average Power you can generate in an hour. A Category 3 cyclist, essentially the level at which people start to take this stuff seriously, will generate, at minimum, an FTP of 3.0 w/kg. So, if you weigh 180 pounds (81.5 kg), 3 w/kg will be about 245 watts.
Therefore, when racing, the percentage of your FTP you are generating provides a direct indication of how you are performing in the race.
Sprint Distance (12.4 miles) = 110% to 120% FTP
Olympic Distance (24.8 miles) = 95% to 105% FTP
Half Distance = 80 to 90% FTP
Full Distance = 75% to 85% FTP
Finally, Normalized Power (NP) is your average power, but takes out anytime cadence is 0 and provides a truer measure of your work output through a given ride that you can evaluate across different rides on different terrain So, your average power is always much less than your Normalized Power, except when you are on a flat course and never coast. Therefore I’ll always have the bike computer set at Normalized Power, Lap Normalized Power, Last Lap Normalized Power, and Power 3's Average (which is the average Power over a 3 second period which, as Power jumps around, balances things out a bit more and a better indicator of what you are currently doing).