TT Pacing with power

Jan 6, 06 19:45

Post #1 of 31 (3331 views)

Sorry for dragging up an old one but I couldn't see an option to PM someone from the older post...

I primarily train for HI and IM and am not interested in much else, but nearby to where I live they do a multi lap tt in a hilly (for me) park. I've always noted with interest the times and wondered how I would fair but usually stay true to my training plans. Anyway being out of formal training (and shape!) I decided I would go up there on my own and have a crack and then analyse the powertap data later (it's new and I haven't used it much).

Going only on perceived exertion my lap splits went 6:05 (353W avg), 6:18 (303W), 6:25 (292W), 6:31 (286W) for an overall power average slightly under 310W. Each lap has a downhill stretch that lasts for about 1:15 (speed ~mid 50's kph, under 200W) and a returning main uphill stretch that lasts for about 2:00 (21-25kph, low 400W say).

I know for a flat tt it worked well to even out the wattage (my only IM I held 225W almost spot on for 3 laps without looking at the comp) but for this type of course would my best time still come from trying to hold say 320W consistently? That would mean backing off quite a bit on the hill but also trying to smash the downhill stretch.

Oh interestingly apart from the first lap where it was noticeable a few beats higher the last 3 laps all had almost identical HR charts which seems to show why power is much better to train off then HR.

Mike

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 6, 06 20:18

Post #2 of 31 (3319 views)

You should hit the hills pretty hard -- about 5-8% above goal average -- and back off once you are back up to high speed (say, 28-30 mph). On any flat bits (headwind or tailwind) move back up to goal average power.

Re: TT Pacing with power [Ashburn] [ In reply to ]

Jan 6, 06 20:49

Post #3 of 31 (3303 views)

Sorry just to make sure I'm clear...you meant 5-8% harder on the climbs, don't try and reach the goal on downhills where speed is high and be right on the money on the flats?

Thanks - Mike

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 6, 06 21:01

Post #4 of 31 (3301 views)

C'mon, you know you want to give it a crack and sign up...It's pretty fun to go all out without having to worry about the run. It would be interesting to see how much faster you went with the incentive of a guy 30 seconds behind and in front of you.

At a weekly TT in Boston (9.75 miles) , 2 of the top 10 men and the 4th pro woman finisher at IMLP this year showed up from time to time, so it can't be terrible for you!

If you were hammering, shouldn't your heart rate have creeped up if your PE was constant?

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 6, 06 22:53

Post #5 of 31 (3280 views)

"Spending" your power on downhills is a bad idea. It takes huge increases in power to go faster as your speed goes up. You are much better off hammering up the hills and soft-pedalling the downhills. Wind resistence is a huge enemy above 25-30 mph.

One of the highest power readings I have seen on my PM was spinning out 54-12 at 60kph or so at 120 rpm. It was fun at the time, but not something I would ever do in a race.

Chad

Re: TT Pacing with power [kdw] [ In reply to ]

Jan 7, 06 1:18

Post #6 of 31 (3265 views)

Yeah I know. Part of the reason for going up there solo was to get an idea for where I stacked up against everyone. The top pure cyclists are about 3mins better than that effort (~25mins total) and the top local triathletes are about 1.5mins better. I deliberatly used the training bike (STI's + std wheels) with a pissy 10min ride there as warmup to see a sort of 'worst case'. Possibly a better prep, bar ends and tri/disc will give a bit more of a drop before I even look at better pacing.

Not sure. I mean 25 mins isn't really that long a time to start getting noticeable creep. Also towards the end it's a fair bet it wasn't HR holding me back but trashed legs flushed with lactic acid. On the final lap when I stood for the worst part of the climb (only about 50m) I almost had to support my full weight on my arms cause I almost couldn't support my weight on my legs!

Re: TT Pacing with power [cdw] [ In reply to ]

Jan 7, 06 1:22

Post #7 of 31 (3263 views)

Yeah I know about the exponential effect of drag at higher speeds, but I was just talking about trying to get the downhill wattage to mid to high 200's rather than at or slightly under. Wouldn't hammering the hills (the first lap was mostly over 500W and the next three were mid to high 400W's) just result in lactic acid debt that doesn't have time to get flushed before the next effort? By that I mean if I backed off to say at the most high 300W's on the climb wouldn't the legs feel much fresher and you could hammer the other sections harder?

Can't recall where I read something along the lines that you have (in the author's eyes) a different set of power zones for hills compared to flats

Mike

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 7, 06 5:33

Post #8 of 31 (3223 views)

You're getting bad advice for triathlon racing (fine for bike racing where you don't need to run after, perhaps). Spiking your power will tire you faster than anything else. Seek to maintain a fairly constant power output. Rich Strauss, I believe, talks at length about this. Google his name to find his website.

Last edited by: jhendric: Jan 7, 06 5:34

Re: TT Pacing with power [cdw] [ In reply to ]

Jan 7, 06 5:37

Post #9 of 31 (3219 views)

Wind resistance doesn't matter one bit if you're using wattage as your guide. 300w is 300w whether it's uphill going 10kph or downhill going 50kph. The only variable at a given wattage is your speed.

And for a triathlon, hammering the uphills is horrible advice.

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 6:13

Post #10 of 31 (3205 views)

I was thinking about the same thing yesterday, so I'm glad some one posted this question. How much time do you lose by maintaining the same power hills? Since your speed is lower, shouldn't 1 - 3 mph difference by not putting up more effort on hills be a much bigger lost to your overall time than backing off a bit on down hills, where 2 - 4 mph is a smaller percentage of your speed? Would you not be helped by the recovery on the down hills? I guess part of it is you don't want to watch people blow by you on hills, but the thinking is you'll be able to get them again later in the time trial.

Adam

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 6:18

Post #11 of 31 (3202 views)

Thanks for the hint Jason, I'll search out the info.

In fairness to the other posters though I probably didn't make it clear that although I race triathlon as my real goals the tt in question is just a road race type and I was curious how to get the best ride for that event.

I was speaking to a guy at work (who is an A grade roadie) who said one of the other top guys who puts in one of the best times for it, tries to sit on 380W with his SRM's, so I was wondering whether that meant the entire lap (ie both up and downhill).

It will be fun to have another crack with a different strategy. One thing though...if you have a certain wattage dialled in, for pure road tt, does it particularly matter if you spin or grind up a hill? It is after all the same work effort no?

Re: TT Pacing with power [adampom] [ In reply to ]

Jan 7, 06 6:26

Post #12 of 31 (3199 views)

You could calculate it over at analyticcycling.com. However, *losing* time is a misnomer. If you mash up the hills and then can't run well because you expended too much energy pushing too hard on the bike, then you really didn't *save* any time at all.

The saying goes something like "for every minute you save by going too hard on the bike you lose two minutes on the run."

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 7, 06 6:29

Post #13 of 31 (3195 views)

"It is after all the same work effort no?"

Wattage-wise, yes. Muscularly, no. It's like the difference between doing 5 squats with 500lbs and 50 squats with 10 lbs. For most people, spinning carries a lower cost, which allows you to maintain your output for a longer period of time.

That said, it's very particular to the rider and their physiology. Ullrich grinds, Lance spins, but you'd have a hard time saying from their results that one style is better than the other.

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 7, 06 7:48

Post #14 of 31 (3171 views)

Check out the power profile charts at cycling peaks (http://www.cyclingpeakssoftware.com/profile.html) if you'd like to know how you stack up.

By the way, it looks like you started too hard since the power is decreasing with each lap.

-jeff

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 8:00

Post #15 of 31 (3162 views)

Wind resistance doesn't matter one bit if you're using wattage as your guide. 300w is 300w whether it's uphill going 10kph or downhill going 50kph. The only variable at a given wattage is your speed.

-----Using wattage on hills is a much trickier proposition. You will gain more benefit from apply a higher power to the uphills and recovering a little on the downhills than you will if you are trying to produce 300 watts on a downhill. Wind resistence causes a point of diminishing returns where you are not getting the same speed gain from your watts.

And for a triathlon, hammering the uphills is horrible advice.

------Indeed it would be, but the original post-er specifically mentioned time trials, not triathlon. However, you would be surprised how many people do exactly that in multi-sport races. I raced two or three hilly races last year and riders would blow by me pedalling like crazy on the downhills, get out of the seat to hammer the first half of the hill and then slowly die out before the top. I sat and spun up nice and smooth and inevitably passed them going over the top. Which they hated and on the next downhill we would start the whole process over again. Eventually they all died and were left behind, except for a few here and there who were a little smarter about their ride.

Chad

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 7, 06 8:44

Post #16 of 31 (3147 views)

I'm a pure time triallist and I have no doubt that I have done much better raising the power on the hills. So, for example, on a very hilly 40K with rollers, I might average about 300 watts, but do the 1-3 minute hills at about 340 watts and then recover on the downhills.

At 40 mph on a -4% slope (about 275 watts), an additional 1mph costs you almost 50 watts! At 15.5 mph on a +4% slope (about 310 watts), an additional 1mph only costs you about 25 watts! Run the numbers yourself and see.

Effective energy use is effective energy use. Whether you have to run afterwards or not doesn't change things. If you have to run afterwards, you follow the same strategy, but reduce your overall expenditure so you'll have some left for the run.

-jens

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 7, 06 9:16

Post #17 of 31 (3134 views)

I can't comment on the power issue, as I have no experience training with it. However, that being said, a weekely time-trial effort in the 20 - 30 minute range is an outstanding training option for triathletes. If your effort is maximal for that time frame, you should be right in the zone that yields excellent improvements in your LT. It would seem counter-intuitive that if you are focusing on HIM or IM distance races that these efforts would help, but they do - as any increase in your LT, increases your effciency and thus speed at ALL paces.

Many, local road-racing clubs host weekly Time-Trials and they are often open to all-comers i.e. you don't need to have a road-racing license to take part. Strange thing is in my experince, few triathletes show up for these! It's a great opportunity wasted in my book.

When I was training seriously, in-season I would do a weekly ten mile TT to gauge fitness and see where I was at. It was not unusal for me to record my season best or life-time best for that 10mile ITT within a week or two of having a great bike split at an IM race or a HIM race.

Fleck

Steve Fleck @stevefleck | Blog

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 10:36

Post #18 of 31 (3106 views)

In Reply To:

Wind resistance doesn't matter one bit if you're using wattage as your guide. 300w is 300w whether it's uphill going 10kph or downhill going 50kph. The only variable at a given wattage is your speed.

And for a triathlon, hammering the uphills is horrible advice.

Let me give you a better example. Suppose you have a 10mi out-and-back course with a 3% grade. With a CdA of .25, If you hold a steady 250 watts, your time will be 29:15. If you go up the hill at 272 watts and back at 166 watts, your time will be 28:52 AND your average power will only be 235 watts!

The only question is whether the overall metabolic cost of the uneven power distribution will be greater. This depends on your individual profile. However, for most people it will not.

--jens

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 11:12

Post #19 of 31 (3089 views)

In Reply To:

You're getting bad advice for triathlon racing (fine for bike racing where you don't need to run after, perhaps). Spiking your power will tire you faster than anything else. Seek to maintain a fairly constant power output. Rich Strauss, I believe, talks at length about this. Google his name to find his website.

I am talking about triathlon. If it was a bike TT, I'd say hit 10-12+% higher on the hills. If I want to average (on a normalized basis) 220 in a half IM, I will hit a short hill (<5') at 240 or so. What Rich is talking about is a guy like me hitting 280+ on hills. We still need to hit the hills harder than the flats, and back off or coast once the downhill speeds up to 27-28 or so.

Re: TT Pacing with power [jhendric] [ In reply to ]

Jan 7, 06 11:14

Post #20 of 31 (3087 views)

In Reply To:

And for a triathlon, hammering the uphills is horrible advice.

Again, I'm not talking "hammering" -- I'm saying lift the power 5-8%. That's hardly hammering. It's staying below threshold/MLSS.

Re: TT Pacing with power [jens] [ In reply to ]

Jan 7, 06 13:32

Post #21 of 31 (3050 views)

Sure, I don't think increasing your power by 8% will kill you, so long as the point from which you make the increase isn't already your LT.

Re: TT Pacing with power [jens] [ In reply to ]

Jan 7, 06 18:40

Post #22 of 31 (3008 views)

OK so you don't try the flat route technique of constant output and it's fine to increase by approx 10% on the hills on your goal overall avg wattage.

I think I might try and go out and avg say 320-330 and see where that gets me, however on the hill I will back it right off as on my first lap I was into the 500W's and every other lap was going into mid 400W's which is obviously way above where you want to let it go from what ppl have been saying?

I think it was pretty clear I went out too hard and then spent too mcuh each time I hit the main hill.

There's a lot of great advice here. Thanks everyone. Now the fun begins....

Mike

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 8, 06 8:16

Post #23 of 31 (2973 views)

Mike,
If that downhill section is right after the uphill (and you didn't specify that), and assuming a sustainable isopower effort of 320W for ~25min course time, I would ride the 2min uphill at ~115-120% of average or 370-380W and let your power drop to 180-200W on the downhill.

Seeing you rode it the first time with the hills at 500W and then mid-400's, this is quite a lot easier and you ought to be able to recover on the downhill.

I have a little 'cheat-sheet' that I use to judge how much I can exceed FT by (for different durations) w/o blowing up. But it does assume you can recover just after the effort - if you have a hill followed by a false flat into a headwind - then all bets are off :)

Again, I'm talking a pure TT effort here ...

Re: TT Pacing with power [mv2005] [ In reply to ]

Jan 8, 06 8:52

Post #24 of 31 (2956 views)

Numbers aside, the best ITT advice I ever got was from one of the top Time Trialests in my area years ago - get to the finish line and know that you could not have turned the pedal another stroke!

Fleck

Steve Fleck @stevefleck | Blog

Re: TT Pacing with power [rmur] [ In reply to ]

Jan 19, 06 4:53

Post #25 of 31 (2871 views)

I had another crack at this and managed to reduce it by a further 13 secs but doubt that's really significant enough to say it was entirely due to a new strategy. The four laps went 6:16 -334W avg(vs 6:05/353 last time),6:18/310(6:18/303),6:18/304(6:24/291),6:13-313(6:31/283) so pacing was better but still would like to drop it down to like 6 flat per lap.

I tried to cap the hill at around 400W. That meant speed around 18-19kph as opposed to 21-22kph last attempt. Speed down the main hill (opposite side of course) was up around 59-60kph as opposed to 53-55kph before. Note there is no downhill after the main hill. It levels off somewhat for about 300m and then there is another slight pickup for about 100m before slight downhill run for say 4-500m.

Anyway I'm now curious what constitutes a decent warm up for a test like this? I'm generally in a rush cause I then head off to work so I just ride up there (about 12mins away) and then get straight into it. I'm wondering what a decent warmup entails?

Mike

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