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Anaerobic intervals decreasing FTP?

St0tanSt0tan Posts: 6
I've read conflicting information regarding the effect of primarily anaerobic intervals (ex. 1 minute sprint w/ 5 minutes recovery) on FTP. Some sources say this type of anaerobic work will decrease aerobic power due to its emphasis on anaerobic energy systems while others say the opposite. Any ides which stance is correct?


  • jgsijgsi Posts: 5,026
    You need to post links to these sources.
    Otherwise we could assume they are ramblings off an ill informed cycling forum.
    If you have reached a level you can achieve through normal training resources, then perhaps you have reached your level.

    Concentrating on an ability to lay down much increased power for a sprint is a worthy goal - a lot to do with luck, technique and bike handling than pure grunt from your 'genetic' makeup.

    It is an interesting point though for those who hold 'ftp' in such high regard.
    As you may gather, it's all wurst to me with racing against people not numbers.
    If I can place highly in races with mid 200 ftp, then I'm happy to draw the conclusion that i probably raced using my head.
  • Tom DeanTom Dean Posts: 1,723
    If all you do is 1 min intervals, your FTP will probably decline at some point.
  • imposter2.0imposter2.0 Posts: 11,003
    5min recovery for a 1min sprint seems excessive.
  • 1-min intervals with 5-min recoveries is primarily an aerobic workout.
  • MishMash95MishMash95 Posts: 104
    In my (limited) experience, I find I get good at what I focus on in the short term but tend to fade at the other things. Last summer when I started cycling, lots of my rides consisted of generally easy riding with a few random hill smashes. As a result, my overall ability to sustain power was bad, but I had a disproportionately good 5 minute power for the time.

    From around November to February, I spent a lot more time focusing on riding at tempo and threshold and it became easier to hold those zones for longer, partially through improvement but also through focus. At the same time, my 5 minute power never really went anywhere and I found VO2max intervals really hard.

    More recently, I started doing a few maximal hill climb efforts and after just 3 or 4 sessions (over 3 weeks), it was like I had unlocked an extra load of power out of nowhere. I upped my 4 minute power PB by 30w (from 340w to 370w) and my 2 minute best effort from 400w to 440w just last week. (The previous records had been set around 2 months before).

    However, I ended last week with a 2x20 sweet spot session (@250w) and it suddenly felt brutally hard after a 4 week hiatus of not doing those zones (partially also had a week off for recovery/illness). I continued doing the tempo riding/sweetspot sessions for a few days and again after about 4 sessions in total, 250w feels completely fine to do, and just today did a 2 hour ride with a normalized power of 235w (which is my highest yet for that duration, and quite far from being maxed out).

    So from that, for me anyway, it seems that when I focus on one area in particular, the perceived difficulty of that area goes down, though potentially at the detrement to another zone, however it doesn't take me long to get my mojo back and shift focus should I need to. Overall, whilst the actual numbers fluctuate for me, my overall average performance is going up.

    I would say the performance potential wont go down, so for example if you had an FTP of 250w but spent a few weeks doing hard anaerobic intervals, I imagine it would feel harder to do steady-state power at threshold, whereas if you had been training at threshold a lot, conversely the anaerobic intervals would feel hard. In essence, the practical FTP may drop by 10w (say if you were to do a time trial) however I imagine if you started doing threshold workouts once again, it would very quickly get back to where it was, however now, you'd have a slightly stronger anaerobic engine.
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