# The wisdom of 90% of 20 min MP intervals?

Discussion in 'Power Training' started by root, Nov 16, 2007.

1. ### root New Member

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I have often seen people recommending doing L4 intervals at 90% of the 20 min maximum power, and sometimes 2 or more 20 min intervals are recommended in single session and some people even claim they do these daily.

Now, this got me curious. How does 20 min max. power relate to FTP? In Andy's book, he claims that threshold power can be estimated by multiplying 20min TT power by 0.93, or 20min MP is FTP * 1.08.

Now, one's 20 min MP might be higher than 20 min TT average power, which means that 20 min MP might be even more than 108% of FTP.

I have seen some people saying that the ratio between their 20 min MP and FTP is 1.1 or even 1.2.

But if this is so, then training at 90% of 20min MP = 0.9 * FTP 1.1 = 0.99 FTP
i.e. these people would be doing their L4 intervals at 99% of their FTP.

Even worse, if the ratio is 1.2, then 90% of 20min MP = 0.9 * FTP * 1.2 = 1.08 FTP, i.e. for these people doing L4 intervals at 90% of their 20 min MP is the same as doing 108% of FTP. This is not longer L4, but L5.

Even, with Andy's estimated ratio of 0.93, we get that 90% of 20min MP = 97% of FTP which is still pretty high and can lead to over training if done daily.

So, I'm beginning to wonder the wisdom of this recommendation. To my mind it could easily lead to over training if these intervals are done daily, or on consecutive days.
It all depends on the ratio of your 20min MP and 60min TT average power (aka FTP). If this ratio is more than 1.1 then doing your intervals at 90% of 20min MP might be too much. You could get the same benefit with perhaps a little less work .

Any thoughts on this.

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2. ### Alex Simmons Member

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FTP is MMP for about an hour, not 20 min. The FTP to 20min MMP ratio is typically around 92%-97%. Everyone is different and your own ratio can vary with training.

I'd doubt anyone would have a 20min MMP to FTP ratio of 1.2.

Physiological adaptations such as raising LT don't require you to ride at 100% of 20min MMP or even at 100% of FTP. Riding below FTP can see some sizeable gains.

The idea of 20 min efforts is simplicity and multiples of these at a lower power than mean maximal you can do more of them, more often thereby having a greater overall impact.

In the end, they are both dominantly sub-maximal aerobic efforts, so essentially what you choose to base 20min intervals on doesn't matter much.

3. ### doctorSpoc New Member

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i do.

4. ### Alex Simmons Member

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What's your 5 min MMP?

5. ### peterwright New Member

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Regardless of the varying individual ratios of 20 MMP to FTP, I cannot see how it would lead to over training. You would be unable to maintain this sort of power day in, day out if you were headed towards an over reaching situation, and would fine that it would be "self policing" in so far as your ablity to train at this level would fade long beofre you were headed towards over training.

For what it is worth I can do 2 or three of these types of sessions per week but if on consecutive days then I will usually find that that power drops off gradually.

6. ### frenchyge New Member

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I would agree, and add that repeating any routine every day without variation would not constitute optimal training IMO, even if it could be done. The original post appears to be a strawman argument to me.

7. ### root New Member

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Thanks everyone for chiming in. I am wondering because I have started doing L4 intervals this week.

I did 2x20 at 95% of FTP every day of the week. However, last night I had to abandon training 15 min into the first interval. I just could not complete it. I tried continuing the interval at 60% of FTP, but I could not even do that. I just felt wasted and then close to depressed that I could not do it. This morning I just did 30 min easy ride.

I always got the impression that one should be able to complete these L4s at will any day. But that's definitely not the case for me, hence I'm wondering.

8. ### daveryanwyoming Well-Known Member

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I certainly can't do 2x20's in solid L4 day in and day out. Even if I could it might raise my FTP more quickly but I doubt I'd get as much overall training load (CTL) with that approach.

I work down in intensity and up in duration during training blocks so it might be something like:
M - rest (active or complete)
T - 2 or 3 x 20 L4
W- 2x30 high SST
Th - 2x45 or 1+ hour low SST/L3
Fr- rest
Sa - L4 or high SST
Su - SST or Tempo

That's this time of year during winter base building and it gets more varied later in the winter and into the spring.

Anyway, it's only one approach but it's mentally and physically managable and provides both intensity and decent CTL building. To be honest I mix it up a bit more than what I've shown over the course of weeks or months but that's the rough idea.

One nice thing about the decreasing intensity, increasing duration approach is that every time you finish a workout within a block you know the next day will be easier. That makes it easier for me to get back on the bike the day after a particularly hard session.

-Dave

9. ### Animator New Member

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Hi Dave, what kind of TSS total for the week does this schedule give you?

10. ### daveryanwyoming Well-Known Member

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This time of year I'm racking up 550 - 650 TSS per week. It depends on how much time I can allocate to the longer rides(Thurs. and Sun.) and whether I can do a double on Wednesday. It's all cycling now but when the snow comes I'll do a few XC skating workouts per week to break things up and because I like to do a few ski marathons during the winter.

-Dave

11. ### acoggan Member

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The original description of level 4 from http://www.cyclingpeakssoftware.com/power411/PowerTrainingChapter.pdf (with emphasis added):

"Just below to just above TT effort, taking into account duration, current fitness, environmental conditions, etc. Essentially continuous sensation of moderate or even greater leg effort/fatigue. Continuous conversation difficult at best, due to depth/frequency of breathing. Effort sufficiently high that sustained exercise at this level is mentally very taxing – therefore typically performed in training as multiple ‘repeats’, ‘modules’, or ‘blocks’ of 10-30 min duration. Consecutive days of training at level 4 possible, but such workouts generally only performed when sufficiently rested/recovered from prior training so as to be able to maintain intensity."

12. ### root New Member

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Thanks Andy. I'm not trying to imply that I got the impression L4s could be performed daily from your book, just to make that clear. But reading the threads here I see a lot of people advocating high volume, high intensity training. So, I thought I would give it a try, and for me it seems to be a little too much.

13. ### Alex Simmons Member

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You wouldn't be alone in that.

14. ### holli New Member

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But you know...You tried to do these every day of the week (whatever that means? 3-7 days?) and that is pretty effin hard and I wouldn't even try that. Two days in a row after rest day is something I would try or actually will do but then the third day would be L3 or even endurance and then rest day. I wouldn't try doing more than three L4 days a week.

15. ### root New Member

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I actually did 2x20 min L4 intervals 6 days in a row. Well, I could not complete the intervals on the 6th day, I was dead tired.

16. ### root New Member

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Well, makes sense really. L4 effort is time trial effort. I don't know if very many people could do a time trial every day and clock in the same or better time, as on the first day.

17. ### Watoni New Member

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Agreed.

My coach had me set a goal of doing 3x20 @ 105% of FTP (yeah, right).

I did 22:30 @106%
then ... 23:30 @99%
finished with 14:00 (different hill) @ 99%

So, I did a solid hour of L4 at 99-106% (not bad for overweight and out of shape); however, it was very taxing and I bet I could have done these intervals at 95-100% and had more in the tank for today. As a "test" to make sure FTP is on target it might make sense but seems less than optimal if the goal is to maximize L4 time and improve FTP

18. ### doctorSpoc New Member

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310W (5.64 W/kg)

19. ### doctorSpoc New Member

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doh!...no i don't have a 20min to FTP ratio of 1.2... it's ~1.12 ...dyslexia is a dangerous thing... 5min is closer to 1.2... ~1.25

20. ### Alex Simmons Member

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