How many watts to knock 30s of 10 miles?
Alex99
Posts: 1,407
Hi all,
after some deliberation, I've settled on my goal for next year: a PB for 10 miles. My current PB is 23:01 which was done when I was 20. I did 23:27 this year on a local course (not the same as the one where I set my PB) @305 W. With everything else being equal, is there a way to estimate the power I would need to hold to knock 30s off? I know I've seen a website at some point where you can input various parameters to get power estimates, but can't remember what it's called.
Cheers
after some deliberation, I've settled on my goal for next year: a PB for 10 miles. My current PB is 23:01 which was done when I was 20. I did 23:27 this year on a local course (not the same as the one where I set my PB) @305 W. With everything else being equal, is there a way to estimate the power I would need to hold to knock 30s off? I know I've seen a website at some point where you can input various parameters to get power estimates, but can't remember what it's called.
Cheers
0
Posts
Unless it's pan flat - some will depend on the course gradients - plus your other factors eg wind & passing traffic.
Any mileage in looking at the slower points and working on them? eg turns?
If you're committed to doing it on a SPOCO, then still look to aero for biggest gains. Any watts you add will help, but that's generally harder.
Also pacing strategy - on a SPOCO often you'll need to go harder on certain sections/in certain conditions.
Anything the calculator will tell you can work out better from reviewing your own ride data with specific info on conditions that day. Also use Strava to look at other people's rides, ideally on same day, and look at their pacing.
I was thinking of it in terms of a target power to aim for, like if I can do 325W for 20-25 minutes in training, then I know I'm in the right area. But, if I can work on other aspects at the same time, then I should do that. I'm sure I have several areas where there is scope for improvement. I can't imagine I'm particularly aero either.
Go on... SPOCO? :oops:
OK, thanks.
I think, if I rode a very fast course, got a PB, but with a lower or same power, I wouldn't be totally happy. I would need to smash the time, and part of it be due to a better athletic performance. So a PB by a small margin on a sporting course would also be fine, I think.
If you want power, focus on power and forget about time... if you want time, focus about time and forget about the power. It seems to me you want to draw a correlation between the two which is not that simple or linear as you would like it to be.
So I think you should attach your goal to a specific course, ideally one you get to race on often.
Also, people often produce different watts in their best TT position, so do your training and testing in that position. You can adapt to aero positions, but it can take quite a long time to get your best watts out. Ideally, get your position sorted first, then start training in that position. Should have you flying by the time racing starts in 2018.
I want both. I was trying to draw a rough correlation, but I'm aware that there are lots of other factors.
OK, thanks. I think I will focus on my local course as you suggest and aim for a PB by 'getting faster'. Sounds like a good point on training in my TT position. I'll try to work on that asap, but that sounds like a rabbit hole in itself.
It's easy to go into the Red on those inclines in a bid to maintain average speed - but better time gains can be achieved by pushing in the flat and downhill sections - which is never as easy to do.
Edited to add this:
https://www.cyclingpowerlab.com/PowerSp ... arios.aspx
I still wouldn't spend time on it though. If you have a power meter (sounds like you do) there's an aero testing functionality in Golden Cheetah. People have been getting decent results with that (need windless day or indoor velodrome if you have access). Combine with some real life data from your course, and you can spend days analysing yourself silly
This is 100% wrong.....
Yeah, I have a PM and I use Golden Cheetah. So it looks like aero testing ahoy. I don't have a tt specific bike, but I do have a second road bike that I can adjust for tri bar use and leave it set up. Hopefully that won't be too limiting?!?
Thanks for that link. If I change nothing else, according to this I need in the region of 20 additional W to make 1 kph which is roughly the 30s.
Speed is obviously the aim. But power is a component of that to work on independently. Like when I'm going to be on the turbo trainier in December.
This. If you can knock out over 300W for a 10-mile TT then either focus on getting more aero or hunt around for some faster courses (or both). Are you on a TT bike? That's plenty of power to be able to put down some very fast times!
Care to explain?
You lose more time on the slow sections, so that's where the biggest gains lie. All pacing strategies revolve around this concept. Harder uphill and into headwind. But not so hard you hurt your performance overall. That's the fine line you need to walk. PMs really help here.
I thought I'd drop into something simple like bikecalculator to blow your answer to pieces .... but it doesn't - working on something simple 2% gradient - the only way I can make pushing harder on the down faster is to make it 9 miles of 2% descent and 1 mile of assent - with 0 flat ... censored ...
and I'd listened to an experienced TTer who said not to push it hard on the hills ...
your 4th sentence is key though - no good busting a gut on the hills/headwind if you can't sustain the effort for the rest of the ride.
Hmm - that'll change my approach for next season
Adding 20 watts to his figures in the table gives around 35 seconds saving, what the OP was looking for.
HTH
Friction with air has poor speed per power return... roughly you cube the extra power needed to gain X speed
Conversely gradient returns speed linearly with increased power.
Hence, uphill, where gradient sucks up more watts than air friction, you get a better return for your extra watts.
It's a balance between the physics and physiology. The latter constrains how much we can vary the power as the more variable our power output, the lower our overall average power will be due to the non-linear physiological responses to intensity (power).
I've studied this topic quite a lot and wrote models to assess pacing and optimisation that accounted for the physics and physiology and also accounted for variations to inputs. I also validated the model by comparing with actual TT power data from club through to world tour riders.
In terms of actual power output over variable terrain courses, there is a time benefit to vary power such that one applies more power on ascents and less on descents. The differences for optimal outcomes are generally not more than +/-10% of average power but it depends on the nature of the course and the climb and descent distances and gradients. Note that typically people already apply more power on ascents and less on descents, the question is then how much variation is optimal. Too little power variation costs time as does too much power variation.
For winds a similar principle applies but it is much less of a power differential for a head/tail wind scenario (e.g. an out and back course), with a little more power into headwind. In such a case the headwind section will take longer than half the time and so one can't physiologically expect to increase power dramatically for that long compared with what they are capable of sustaining for the entire duration.
But while the optimal power output strategy is one where power is higher on ascending sections of a course, this can be quite different when expressed in terms of a subjective rate of perceived exertion (RPE).
In RPE terms, you actually need to feel like you are not over pushing the ascents and that you work the descents quite hard. That's because what typically happens is people go too hard on the ascents (in power terms) and not hard enough elsewhere. So what feels like going a little easy on climbs and working hard down the other side actually still results in higher power going up than down.
If people really want to learn more, there are more detailed discussion on this topic on various forums.
"people go too hard on the ascents (in power terms) and not hard enough elsewhere"
Definitely applies to me. On my local 10 there's a drag and a bump after the half way turn. I end up in the red after this and struggling to get 250 W for a few minutes when it flattens out. Way more than the suggested 10% variation in output. Very useful practical advice.
A true mean maximal iso-power effort is actually quite a fast strategy, while a subtle variable pacing strategy will be quicker again. Trying to get fancy beyond that there is not a lot of pacing gain (and there are multiple pacing variations that are all essentially optimal).