Intensity Factor. Intensity Factor (IF) is a the ratio of the Normalized Power (NP, see above) with your Functional Threshold Power (FTP). The concept of IF is introduced by Andrew Coggan and is. FTP is a measure of a steady power output you can sustain for an hour; that's very different from the kind of sprinting/coasting you find in crits. Normalized and FTP are probably in the same ballpark, but are in no way the same, and the difference between the two measurements-if you're like me-may be large.
Usually I'll do a 20 minute steady all out interval and use 95% of the average power to estimate FTP every month or so, but for no reason in particular, I haven't done that in about 2 months. I have done a few 1 hour criteriums, usually in a breakaway (see: possibly have no fast twitch fibers + sad clown sprint power :)) so the effort is pretty much red-lining for an hour. How would 1 hour normalized power in a situation like this compare to FTP? I'm not sure if it matters, but my 1 hour NP recently seems to be about 15 watts higher than my FTP (as measured at 95% of 20 minute power) 2 months ago. I'm just curious how 1 hour NP tends to compare with FTP. Thanks for any input r/velo
In previous posts on the Using a Power Meter series, I defined Functional Threshold Power (FTP) and its importance in the athlete development process, and described several methods you can use to estimate FTP. Next up is normalized power (NP), which is a very important concept when it comes to using a power meter. You are probably familiar with average power, which is simply the mean watts generated during a ride or a particular segment of a ride. Normalized power is an estimate of the power you could have maintained for the same physiological cost if your power had been perfectly constant such as on an indoor trainer. NP is the superior measure because it takes surges (i.e., harder efforts during a ride) into consideration.
For example, let’s say you complete a 1-hour, Zone 2 ride at a steady pace and your average power is 190 watts. The following day, you complete four hard 2-mile hill climbs and recover by spinning back down the hill. Once again, the total workout takes 1 hour and your average power is 190 watts. Now, was the physiological effect the same for both workouts? Absolutely not! The hill climb workout was definitely harder and would have created more physiological stress. That’s the beauty of normalized power. It takes the hard uphill efforts into consideration. With the first workout, your average power was 190 watts and your NP would have been very close to 190 watts as well (because there were no surges). Conversely, with the hill climb workout, your average power was 190 watts but your NP would have been much higher (e.g., 220 watts) to account for your hard surges uphill. Because of this, you should always consider normalized power when analyzing a workout or a particular segment of a workout.
NEXT POST – March 1, 2015
Cycle Log: Intensity Phase 2015 – Week 15