How to aim for power targets with short sprints?

I have a direct drive dumb trainer, an Elite Volano, which I use in conjunction with my 4iiii power meter. So setting the power level is up to me. Since starting structured training with TR this spring, I got a lot better at accurately hitting power targets within a few watts. However, I am struggling with short, hard bursts such as 5- or 12-second sprints at 200 % FTP or so. I can do the efforts alright, but either I slightly undershoot by about 5 % or overshoot by sometimes as much as 15 %.

Essentially, I would like to know whether I should aim for hitting the instantaneous power target, even if that means undershooting the average, or whether I should try and stick to the target of the power average with short, hard efforts?

Not hitting or exceeding the averages makes me feel I didn’t do my homework properly, so I usually try to err on the side of going harder. Here is how I do it currently: about 5 seconds, I switch to my large chain ring and then 3 seconds before the sprint starts, I start winding up so that at the beginning of the sprint, I am roughly at the desired power. For VO2max efforts I am quite accurate in hitting the power target, but not so when it is 2x of my FTP. Very often, I am below it and in order to hit the power goal (i. e. the average over the course of the interval), I push harder (say, I do 670 W when 600 W are what is asked for). Oh, and I have set power smoothing to 2 seconds. I could wind up earlier, but that could get quite punishing in some workout where I have to do quite a few sprints, some are during threshold intervals.

Any advice here?

I don’t have my advice, but just to say I can’t do it either. Even with erg mode on a smart trainer I overshoot at first.

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I wouldn’t worry much. From what i understand the aim is to train the ATP-PC system and an exact power target is not that important as long as you give it a really good kick. When I used a “dumb” trainer I just gave it all the first seconds and just held on for the remainder of the interval.

There may be different opinions and this forum tend to over analyse things (:heart:) but sometimes you just have to work with what’s reasonable.


I really struggle with this is well, as the efforts repeat themselves I tend to pick tweak the gear and cadence as soon as that will result in the desired power once the speed sensor and power smoothing has caught up and do it more off cadence. I know ‘that gear’ and 105rpm say will give me my target eventually.

I don’t really know how else to do it with virtual power but I can’t switch up even 5 seconds before the interval in some cases without blowing up (you would end up doing 20 on 10 off instead of 15 and 15 for example and that surely changed the workout!)

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For power durations that short it’s better to perform them without ERG enabled. Just changed down a couple of gears before the start and go for it. To be honest, close enough is good enough when it comes to intervals like that, so if you’re aiming for 600 watts and hit 700 then don’t worry about it, it’s still having the same effect.

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He is using a dumb trainer that lacks ERG mode, so that is not part of his issue.

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I always think that with these kind of efforts they should replace the target power with a flashing banner saying GIVE IT ALL THE BEANS.

For me, I’ll tend to use sprints indoors to work on leg speed rather than pushing a big gear.

Agreed. IMO ignore the power target and just send it for the duration.

no biggie if it’s 5%

probably want to steer away from this as it might make the next portion of the interval not possible

are these just 5-12s as mentioned above? If so, get as close as you can.sounds like you need some PMAX work along with these intervals that you are currently doing.


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Yes, I was referring to those. Anything longer than that (such as 30-second VO2max efforts at 120-130 %), and I can pace it relatively easily and precisely.

I was thinking of dedicating some time during the off season to sprint work anyway, which is one of my weak points.

well to be honest, that’s because 30s is not vo2max. You haven’t burned off anaerobic contributions in that portion. you wont get solid work in until you hit at least a couple of minutes. vo2 is when you’re truly gasping for air.

so, if doing 30s, you need to go harder, or if doing 120%, you need to go longer to get true adaptations.

Perhaps we have gotten our wires crossed: I am not having problems completing what are described as VO2max workouts. I wanted to know whether I should aim for instantaneous or average power when doing very short efforts such as 5- or 12-second sprints.

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Which workouts?

Examples are Ebbets, Clark or Hunter.

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Read the workout goals, it’s about quickly delivering a surge of power. I would focus on quick delivery and holding it, and wouldn’t bother paying attention to exact numbers.