Sunday, June 7, 2009

40k TT Pacing Example

This is yet another post from me on pacing steady state events such as time trials and triathlons. By now you should have gottten the idea that I think this is a very important topic, but one that is all too often overlooked by athletes in their race preparation.

Here you see the chart of a well-paced, 40k time trial by one of the athletes I coach. It's a "stand-alone" race (not part of a multisport event). The black line is power and the red is heart rate. The chart is broken into 10k quarters.

We have been working diligently on her mental approach to race pacing since I started coaching her in January. In this race she did an excellent job of breaking the course into quarters as explained here and managing each as individual races. Her fourth quarter proved to be her best as you can see from the power increase near the end. But the best indicator, one that I always look for, is how well the third quarter went. This is when riders typically fade if they did a poor job of pacing in quarter 1. In this quarter her power was within 1 watt of the first two quarters.


At June 8, 2009 5:36 PM , Anonymous Anonymous said...


Thanks for the recent posts on time trialing. In terms of pacing, on a 40k TT, is it better to roll off the line right at threshold and come up to speed gradually, or better to jump off the line to get the bike right up to speed.

Seems like getting quickly up to speed would be ideal, but I worry that those 8 or 10 seconds at 200% of FTP could come back to haunt me by the end.

In case it's relevant, these are TTs with no starting ramp.


At June 8, 2009 8:05 PM , Blogger Joe Friel said...

Daniel--I'd suggest about 12 seconds of very high effort to get up to speed quickly.

At June 9, 2009 8:50 AM , Anonymous Anonymous said...


Some great info here, thanks for sharing. Can you elaborate a bit on the power profile in terms of %FTP for each quadrant of the ride? I'm thinking back to your earlier comments about delaying onset of lactic acid and wondering if for optimal 40kTT you would look to build from say 95% FTP in Q1 to ~105% or so in Q4? (No idea if these numbers make sense, offered just for clarity.)

Scott F (Calgary)

At June 9, 2009 2:17 PM , Blogger Joe Friel said...

Scott F--Very good questions. You could do it that way. But it may not be so much that there will be a change in power output, but rather an elongated increase in one's rating of perceived exertion (RPE) if paced correctly. Assuming the course is flat and wind is not a factor (unusual, huh?) you would want to average your FTP if it was a 1 hour race. Here are the two ways... 1) You could start by riding below FTP by some small amount and gradually increasing power so as to finish above FTP. Or 2) you could simply maintain FTP all the way which would mean it would feel easy for the first several minutes (low RPE) and only gradually become more challenging (RPE increase). But because there are seldom courses that are perfectly flat with no wind, there will need to be some adjustments to both power and RPE throughout the race. So the bottom line is that both will shift a bit throughout the race. But, assuming a relatively flat course, the bigger shift should be in RPE rather than in power. This is a great challenge for the rider who does few TTs and seldom rehearses/practices for them. It's a matter of patience and emotional control.

At June 10, 2009 9:56 AM , Blogger Don said...

Send a congrats to your athlete and a one to yourself for the coaching.
One question about her chart: In Q3 do I actually see a decrease in HR and an increase in power during the second have of Q3? Was there a reason for this (mental, physical, environmental)?

At June 10, 2009 10:05 AM , Blogger Joe Friel said...

Hi Don--Thanks on behalf of my client. Here are her power-HR ratios by quarter...

Q1 - 1.02
Q2 - 1.0
Q3 - 1.0
Q4 - 1.06

In Q2 her HR rose a bit as she warmed up. Power and HR remained constant in Q3. In Q4 power increased more than HR did which is a good thing. This also implies that she may have held back too much in Q1-Q2. But I'd rather have that than the opposite: Fading in Q3-4 due to being too aggressive in Q1-2.

At June 17, 2009 7:17 AM , Anonymous Brian said...

Hi joe,

I follow your work and love your research studies but i'd be interested to know what you think in the topic of chainring size for a guy(myself) that has load @LT 400watts. hr @lt 166.
It is regard to cadence also because this athlete tends to run better on a lower cadence but when he is putting the power on and speed the cadence goes up on the 53! Would an up grade of to 54 make a difference to performance??
Do they make a difference?
Would the 54 be to harsh on a hilly course??

I would be interested to know your view.

At June 17, 2009 7:45 AM , Blogger Joe Friel said...

Brian--Many riders use a bigger chain ring such as a 54 when time trialing. This will tend to slow cadence while increasing force. This is generally best for riders who are more adept at mashing big gears at low cadences. Those who feel more comfortable at a higher cadence typically don't do as well with a bigger chain ring/higher gear combination. Sometimes age is used as a reason to go to a higher gear combination/bigger chain ring. I traded emails with a European pro cyclist on this issue a few weeks ago and advised him not to even though he considers himself 'old' now in the pro peloton. He still prefers and feels most comfortable at high cadence when TT'ing. And you're right on the last point also: A bigger ring may make climbing more difficult.

At June 17, 2009 8:09 AM , Blogger BMC said...

Thanks joe.. Always insightful..

At June 19, 2009 4:14 AM , Blogger BMC said...


Would it be fair to say that you should come home with an average HR of just under threshold on a 25TT.


At June 19, 2009 6:33 AM , Blogger Joe Friel said...

BMC--If by 25TT you mean 25 mile and it takes you about an hour then I'd say it will be threshold HR +/-5bpm.

At June 19, 2009 7:13 AM , Blogger BMC said...

Yes joe 25 mile. I did my first last night. i know my hr threshold is 166 so i set an alarm on my garmin if i rose above it. (it worked a treat). Kept it in and around 166 for the first three 1/4's and then gave it what i had on the last!.
it was windy and rained on the last 10k or so but came home with 55.27

thanks for your help as always and i love pickin up little tips on your blog!!



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