Coggan's power levels

ptooey said:

Hello,
When you guys do either 2x20s or 5x5s do you do them at the prescribed power level and no more or do you do them at the max level that you can maintain for the time interval? Just wondering.

i think the idea is that both levels are the same - ie if your threshold power is 230 watts and your vo2 max power range according to cyclingpeaks is, say, 250-280 watts, then the prescribed level for a 5 min interval may be 250-280. so long as your threshold power is a good estimate, then you would find that 250-280 would be the max sustainable, depending on how rested or good you were feeling.

It's a bit tricky because your FT can vary a bit everyday. It depends on recovery, stress etc.
What I do is: I start the first interval a bit below target wattage, see how I feel, if PE is too high then I maintain or decrease power for all intervals, if PE is normal then I push a bit harder during the next intervals.
What I always try to do is to maintain the same power output (with +-5w more or less) during all the intervals, intensity should be high enough so that before the last interval/s I think I won't be able to finish it/them.
Just my 2ç

ptooey said:

Hello,
When you guys do either 2x20s or 5x5s do you do them at the prescribed power level and no more or do you do them at the max level that you can maintain for the time interval? Just wondering.

I'm assuming that by 2x20s you mean Z4/Threshold intervals and by 5x5s you mean Z5/VO2max intervals, as per Coggan's zones.
If you have calculated you Functional Threshold power correctly, you should complete your intervals such that Avg. power for the 5x5s is within Z5 and the Avg. power or Normalized power for the 2x20s is within Z4. This does not mean that every second of an interval must be exclusively within Z4 or Z5 of the respective efforts (e.g.: a 20min Z4 effort is likely to have a few data points in Z3 and Z5): although I would suggest that wild fluctuations could result in adaptations that are not specific to the desired efforts/training levels.
So, specifically to your question, I would recommend your first scenario, at least for most workouts. *Always* performing intervals at your maximum effort is likely to burn you out, is unnecessary to obtain the desired physiologic adaptations and could result in unintended adaptations (i.e.: increased anaerobic vs aerobic adaptations - at least for shorter intervals). However, occasional maximal efforts can be used as testing and are certainly a way of setting (eg) Functional Threshold power.