Originally Posted by awilki01 .
Dave,
Can you explain the 75% of the 5 minute power? And, if that is an issue, how can it be overcome? I've been training for about 2 years now. I'll be 40 next year. I don't directly test my 5 minute power, but looking back last year, I may have tested it once and it came in around 300 watts. My FTP is somewhere between 240-250 watts. Since I'm still new to the sport, wouldn't SST also pull up my 5 minute power as well? Or, does it look like I may at some limit right now?
Sure, it breaks down like this:
- 5 minute power is a convenient proxy for power at VO2 Max (p_VO2 Max) or the power that's generated aerobically at an athlete's current maximal O2 exchange rate (which is different than the range of power/durations that can elicit VO2 Max respiration but that's a different discussion). It's not a perfect proxy as 5 minute power contains a substantial contribution from anaerobic energy production but it's not bad as a rough estimate and it's fairly easy to track peak 5 minute power but a bit harder to actually track p_VO2 Max.
- p_VO2 Max represents the maximal power an athlete can generate via purely aerobic processes. Riders can certainly generate additional power for short durations but any power above p_VO2 max comes from anaerobic energy production and is not sustainable for very long. Again it's tougher to track actual p_VO2 Max without either lab tests using gas exchange masks or by inferring it from things like a well paced 3km to 4km pursuit type effort where the start depletes most of the anaerobic contribution and the remainder is performed very near p_VO2 Max so we tend to substitute 5 minute power for convenience.
- VO2 Max as a gas exchange rate in liters per minute (or more commonly weight scaled in ml/kg/min) sets the current upper bound for aerobic power generation and although it is trainable over time it tends not to move very much after the early stages of training.
- FTP or power at LT as a fraction of p_VO2 Max is much more trainable though it takes a long time to train. This is our primary focus when we do SST/L4 training or even when a full time rider racks up lots of hours of LSD base training. We're working on improving our FTP as a percentage of p_VO2 Max. And yes, this stuff is not entirely discrete so when you do a lot of SST/L4 work your p_VO2 Max tends to increase as well.
- FTP as a fraction of p_VO2 Max can span a wide range in different athletes depending on training history, state of current training, and genetics but it's generally in the range of approximately 70% to perhaps 90% or maybe a little more in some exceptionally well trained athletes. Based on the folks I've worked with 80-85% is pretty typical for FTP as a function of 5 minute power after a few seasons of consistent training but a large part of what we work on is trying to move that number upward with SST/L4 work.
- If a rider trains their FTP up above 85-90% or more of their maximal 5 minute power (and that 5 minute power really is maximal in that they've really tried and not just cherry picked a 5 minute effort out of random riding) then it's possible that they're 'running out of aerobic headroom' or IOW, their FTP is such a high percentage of p_VO2 Max that further progress in terms of the FTP/p_VO2 Max percentage is becoming less likely. At that point we typically introduce additional focused VO2 Max work in hopes of raising the athlete's 'aerobic ceiling' to give them more room for further FTP development. This typically doesn't happen till an athlete has five or more years of steady high quality training under their belts and have ridden the FTP development train for several seasons. FWIW, be very careful here as many riders IMO jump to the conclusion that they're run out of aerobic headroom and scrap SST/L4 training in favor of VO2 Max training much too soon and end up slowing their long term progress or often burning out on high end work in hopes of speeding things up. There are a lot of good reasons to introduce VO2 Max work even if a rider has a lot more room to develop FTP, for instance pre season race prep for races that will demand a lot of VO2 Max style efforts but even then most folks should get back on a good FTP building program post season during their winter build. Just don't think VO2 Max work is magic in terms of FTP progress as for most folks, it's not.
So when I see a rider who's recorded a 5 minute MMP at 403 watts and starting this thread reported an FTP of ~260 watts or FTP is only 65% of 5 minute power it seems likely that the athlete has a lot of room to grow and likely could do much better for a full hour just with some work on pacing, mental focus and fatigue resistance. Freddy's recent progress to actually ride an hour at 295 watts (awesome BTW!) puts him around 73% for FTP/5 minute which still implies a lot of room to grow. Sure a 'fast twitcher' who's 5 minute MMP reflects a lot of anaerobic contribution isn't likely to ever get their FTP/5 minute MMP up into the 90% range but 80% or more is pretty typical for well trained riders.
Anyway, that's the back story on my comment above. Hard to say how far Freddy can take this, but if that 5 minute power number at over 400 watts is accurate and repeatable then I suspect his FTP will continue to climb for a while and that he's nowhere near his aerobic ceiling at this time.
-Dave