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Normalised power for Chaingang Vs TT power

joeyhalloranjoeyhalloran Posts: 806
Recently I have been finding that the NP I come home from a chaingang with is much higher than I can sustain for even a 20 minute solo test.

My average NP from chaingangs has been around 290w for 50mins-1 hour ish, yet yesterday when I tried a CP20 I couldn't even hold ~300w for 10 mins.

I am not quite sure why there is such a drastic difference in my performances. I had a break for the past few months and only been cycling again for the past 2-3 weeks...maybe I have lost the ability to push myself individually? Anyone else found this?


  • BronzieBronzie Posts: 4,927
    It's not unusual for NP in a highly variable intensity ride to be up to 5% more than steady state. For instance I did a 2-up TT last week with NP=286W / AP=271W, whereas the week before solo I did NP=267W / AP=264W.

    I certainly find it hard to push myself as hard as I can when in a group where I will "go 'til I blow". The 2-up certainly left me pretty empty.

    Another possibility is that your relative freshness (only 2-3 weeks training) leaves you more capable of the repeated anaerobic efforts needed in a chaingang rather than steady aerobic work.
  • amaferangaamaferanga Posts: 6,789
    I think NP overestimates for highly variable efforts such as chain gangs or races. I've done several races where my NP for almost 2 hours has been 10-20W higher than what I can sustain (steady-state) for an hour. I've seen 2 hour NP from races even higher than I managed in a 10 mile TT I did a couple of months back. None of my other ride data suggests that my FTP is wrong.

    Interestingly, xPower (in Golden Cheetah) for races is always significantly lower than NP and entirely consistent with my steady-state efforts. NP for races or chaingangs may be good for the ego, but I don't really take much notice of it anymore.
    More problems but still living....
  • MountainMonsterMountainMonster Posts: 7,423
    OK, at the sake of sounding slow, but could someone explain these terms?
  • BronzieBronzie Posts: 4,927
    OK, at the sake of sounding slow, but could someone explain these terms? ... score.aspx

    Normalised Power is a metric produced by power analysis software that is supposed to give a measure of power output for rides where power output is highly variable (ie road races, chaingangs). The higher your output above your threshold power, the higher fatigue you will accumulate.

    You ride for 1 hour at 200W.
    The next day you ride for 1 hour alternating between one minute at 400W, followed by 1 minute coasting.
    The *average* power for both rides will be 200W, but the second ride will be much harder and will score a higher *normalised* power.
  • MountainMonsterMountainMonster Posts: 7,423
    Ah, awesome, is it quite a good training tool?
  • joeyhalloranjoeyhalloran Posts: 806
    I would have thought with lack of training anaerobic/top end stuff would be quicker to go. It is interesting though, I will try another CP20 sometime soon and not make the mistake of estimating a power (I will just go on feel and see what I get).

    That is interesting because I have often noticed my xpower and NP are very similar for a lot of the rides I do, I will try uploading the CG into GC and see what happens.

    It is quite a useful tool because it allows you to more accurate set power bands for intervals. I.e. if you set your self so many intervals at x power with rest at y power and calculate the NP, if it is higher than you can sustain for that period of time the chances are you won't be able to complete the session.
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