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P.S. In those months of racing I did have one “great day” where the power meter let me down. I realized about 2/3rds of the way through the ride that I was just sandbagging, regardless of the numbers and just punched it. My ride for 1:30 nearly equaled my CP30 from three weeks earlier and I ran an incredible split afterwards. Generally though, the PM keeps me in check and lets me ride and run at the paces I am capable of maintaining, not the paces I would like to hold

I tend to go OK just on HR for the half IM distance. out of curiosity, how much does going too hard for the first 15 minutes of an IM and then settling in to your "right" pace affect your run, if you have several hours to go.

My thought process to this is that if you are having a bad day (it happens), power output will be down for a given level of exertion. So if you try to ride at the prescribed power output, then you are actually going too hard, no?

Where I do see power measurment being beneficial in a race situation is on hills, since there is a lag between changes in effort and the HR response. The PM can help you throttle back at the start of a climb, if your tendency is to ride hills too hard.

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The only thing that proves is that your CP30 value from 3 weeks earlier was wrong nothing more.


How can a CP30 be wrong? It is what it is. It was the fastest I could ride for 30 minutes followed directly by a three-mile run TT. You try and control the factors to make it somewhat accurate, but it gives you something with which to work. Most of my races for the rest of the spring were pretty accurately gauged by that particular test. I just had "one of those days" when all the right factors came together and I was flying.

Chad

You need to pace yourself really well in a 4 minute event. It is not max effort from the start, as its impossible to sprint that distance. If you go out too hard you'll blow up big time. 2-4 minute events are actually some of the hardest to get right.

Boardman had a PM, he was one of the early adopters. He used it in training and in some races, to gather data so he and his coach could fine tune his training programme. He rode at least one TT in le Tour with the SRM handlebar unit strapped behind the seat.

I tend to trust what the pro's do, since they spend a lot more time thinking about their training program than the average AG'er. I don't see a lot of pro's (triathletes or cyclists) with PM's on their bikes at the big races. Some, but not a lot.

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<<I tend to trust what the pro's do, since they spend a lot more time thinking about their training program than the average AG'er. I don't see a lot of pro's (triathletes or cyclists) with PM's on their bikes at the big races. Some, but not a lot. >>

To the pros, pacing doesn't matter as much. Either they are faster then the people around them, or they are not. If they go out too hard and blow up (which many do), the only result is them not finishing and getting flamed on by a bunch of P3C riding, man bra wearing, types who can guess at wind tunnel results by a pic on some internet forum.

Most cyclists I know who race with a PM, only do so to look at the data later, and some will even put tape over the display to keep from looking at it and worrying during the race.

GREAT NEWS Cam... glad to hear that your PT is working out for you. Now you just need to get back on a TRI bike ;-)

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I tend to go OK just on HR for the half IM distance. out of curiosity, how much does going too hard for the first 15 minutes of an IM and then settling in to your "right" pace affect your run, if you have several hours to go.

I have never done an IM, however, a couple of friends who raced in Hawaii and swear by powermeters have noticed that people go really hard for much longer than 15 minutes and then blow up at the end of the ride. When you do this running, you end up walking. Which is much, much slower than running. If you do it on the bike, it may not be as noticeable, but I expect the effect would be similar. These same athletes passed a lot of people late in the ride and then ran solid marathons.

For Half-IM I use a combination of heart rate and power to keep tabs in the early part of the race.

My thought process to this is that if you are having a bad day (it happens), power output will be down for a given level of exertion. So if you try to ride at the prescribed power output, then you are actually going too hard, no?

This is totally correct. After my best ever half-IM last fall I raced another later in the year and just didn't have it that day. The power was down, heart rate and percieved exertion were up and I realized it was not my day. Had I been smart I would have bailed at T2. A bunch of my family had come to watch, so I felt a little obligated to give it a go. By mile 3, I was done and ended up in the ambulance. I have no idea what happened. I probably just bonked really hard at the end.

Where I do see power measurment being beneficial in a race situation is on hills, since there is a lag between changes in effort and the HR response. The PM can help you throttle back at the start of a climb, if your tendency is to ride hills too hard.

This is true as well. I raced duathlons at Camp Pendleton, Ca., Powerman North Carolina and Duathlon nationals and they were all rolling to moderate hills. This is how the ride went. I was out in front after the opening run and riders would start to go by, riding hard on the downhill or the first third of the climb. After about a third of the climb they would stop gaining on me as I find the right cadence and work into the hill. They tended to struggle along in too high a gear. Near the summit they will be slowing, thinking the hard work is done and I would roll right by them then, accelerating over the top. . This will annoy them and they would attack and go after me and pass again on the next downhill, starting the whole process over.

I learned another useful lesson at Du nationals when I was trying to get rid of a draft pack. I waited for a hill and then gunned it to try and catch them all at once. When I looked down at one point I saw 450 watts. That’s where the stupid meter kicked in and I stopped trying to ride away from them. It turned out to be a good choice. Most of the penalties in the race were given to that pack and I blew by all but one of them on the run. They put 90 seconds or so on my in the last 10-15K, but I outran most of them by three or four minutes in a 5K. Powermeters are not the answer to all of race pacings problems, but they sure are a useful tool to get the most from whatever God, your training and good timing have given you to work with on a particular day.

Chad

I tend to trust what the pro's do, since they spend a lot more time thinking about their training program than the average AG'er. I don't see a lot of pro's (triathletes or cyclists) with PM's on their bikes at the big races. Some, but not a lot.

What pro cyclists use in a race is not a great indicator of what may be useful to an age group triathlete. The pro cyclist is far more experienced, he doesn’t have to run after words and non-time trial events do not require linear efforts. An earlier thread told that roughly half the top-20 finishers at Hawaii this year used PMs, to include the winner, so that seems pretty good evidence that some pro triathletes think a PM is a good idea.

Thanks for the insight. Just wondering how many of those top 20 pros were using the PM to pace themselves, and how many were using it to gather data for their training programme? Just food for thought, I don't think any of us have the answer to that.

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Your post mentioned that your PM "let you down" and that you then kicked it and finished with a time nearly equal to your CP30. I read into that that your pacing was somehow linked to that CP30 value and you were going too slow as a result of that. Correct or am I way off? My point was that your CP30 value can be wrong even if it's your best effort on the day. Fatigue or lack of motivation can give you a low number. If in the race your CP90 (race time) was almost equal to your CP30 then clearly your test result was low.

Pacing with a PM only works if you have a really good idea what your FT or CP numbers really are. Not possible for a PM to let you down (unless it breaks) and provide bad pacing guidelines. Only incorrect assumptions about your power is can do that.

Yeah...screw using HR unless it is WAY off your expected readings. The people I see dismissing it have minimal or no experience using a PM. Or they want to apply it to road racing where it obviously has less value in that either you stay with the pack or get dropped.

There really isn't anything more powerful than performing a race simulation with power...its borderline cheating. To show up at the race knowing exactly what you are capable of and, more importantly, what you are not capable of is invaluable.

ot

All very good points. A powermeter is just a tool and not responsible for anything. However, it does give you a baseline with which to work and gives you some absolute numbers that you know are bad. For instance, during duathlon nationals this year I tried to get past a draft pack that formed up about 20-25K into the ride. I look down on one of my pass attempts and saw I was pushing 450 watts. I immediately abandoned the attempt and let the pack roll away. At the time the effort seemed hard but not impossible and without power feedback I might have kept on cranking those 450 watts for a bit and paid the price later.

As it was, I went on to a pretty good run and caught all or most of the 15 or so riders who were involved.



I think even the most experience riders misjudge the perceived exertion vs. actual output. Our brains and bodies are not machines. Of course, no one would ever break a record if they only went as fast as they thought they could go, so PM data has to be one part of the equation, but you should not be a slave to the numbers.



Chad

The time to test how hard you can go, IMHO, is during base building when you are doing your FT (functional threshold) intervals (used to approximate CP30 or CP60 watts). A typical FT test is 2x20' at FT watts with 2' rest, then you look at normalized watts for the entire time, and that's good enough to approximate CP60. So next ride say you are doing 3x12' (2') at FT watts, you can "test" whether you can go 5% higher. The test comes whether you can hold the same watts for all 3 intervals. If not, you aren't ready to go harder. If yes, then try again next time. Repeat until you get stronger.

Ride and test, ride and test, race (also a test), repeat. Nothing magic about it, just much easier with a PM.

I'd suggest buying, training and most importantly, racing with the power meter.

As someone who was previously really impressed with my perceived exertion-o-meter, and someone who does a LOT of TT's, and is only racing a bike (so you'd think I'd have it figured out), I'm come to the realization that my pacing is lousy--and I still think I'm better than most! I won't race without it again.

Also, the longer the event, the more difficult pacing can become, so I can't figure why you wouldn't pace a long TT without a PM, especially when you have to run afterwards.

There are a lot of great quotes in this thread:

1."I just used my Tacx trainer and I know what perceived exertion equates to 200W vs 250W vs 300W vs 350W and I can take perceived exertion with me on the road, and it will never crap out in bad whether or electrical malfunction."
that one's so ridiculous I don't know where to start

2".If I'm in a race, all i need to know is if somebody is ahead of me (which there usually is), and that means I have to go faster."
Pacing yourself on someone elses speed seems pretty foolish to me.

3."They aren't really for pacing, since they measure only the output and not the cost of the output. HR & perceived exertion give a better (not perfect, but better) indication of pacing in a race."

huh?? that's EXACTLY what they measure, the metabolic cost of the event??

4.I tend to trust what the pro's do, since they spend a lot more time thinking about their training program than the average AG'er. I don't see a lot of pro's (triathletes or cyclists) with PM's on their bikes at the big races. Some, but not a lot.

fast forward 5 years from now--do you think that you'll see any pro's racing w/o PM's...no way to tell for sure, but I know where my money is on that one. Way too many pros are too full of themselves to recognize their own limitations. Look at Brad Wiggin's worlds TT to see how a top, world-class TT'r can get it totally wrong in a big event.

As long as your competetors hold onto these beliefs, you'll have a competetive advantage using a PM.

A couple of my statements are in there, so I'll respond. To clarify, I never said that perceived exertion is perfect, and I think PM's can be a great training tool. For longer races and race simulations, I'll always use a HR monitor rather than rely only on RPE, but RPE is pretty accurate for me.

Maybe you can clear something up for me. How exactly does a PM measure metabolic cost? It doesn't measure anything happening inside your body, only the outcome. If you are having a bad day, the metabolic cost will be higher for a given power output.

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"How exactly does a PM measure metabolic cost? It doesn't measure anything happening inside your body, only the outcome. If you are having a bad day, the metabolic cost will be higher for a given power output."

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Raw power doesn't, but "normalized" power is intended to measure metabolic cost.

http://www.midweekclub.com/powerFAQ.htm#Q16

Q: What are “normalized” power, intensity factor, and training stress score?[/url]



A: Created by Andrew Coggan, Ph.D., a noted exercise physiologist, this is obtained via an algorithm that adjusts for variations in power with reference to lactate threshold and other physiological responses.



Suppose you race a 1 hour criterium, where you are frequently sprinting out of corners, covering breaks, etc., and you race to your limit, such that there are very few if any slack periods. Average power with coasting time will nonetheless be considerably lower than a flat 1 hour time trial where you paced steadily and had nothing left at the end, yet you feel just as stressed physically. The normalizing algorithm adjusts for variations in power, such that the resulting normalized power value will be very close to what you would have achieved in a TT of equivalent duration. In short, it is meant to more accurately reflect the actual metabolic strain that the body incurs, rather than the average stress load imposed.



Here’s how it is calculated: first, a rolling 30-second average (mean of the last 30 seconds) is applied to the wattage values from the downloaded workout file, since the body does not respond instantaneously to rapid changes in exercise intensity, rather, most physiological responses follow a predictable time course with a half-life of approximately 30 seconds. Next, each of the values obtained from this is raised to the 4th power, just as blood lactate response has been shown to closely fit the plot of y = x4, where y = blood lactate and x = power output; indeed, many critical physiological responses (e.g., glycogen utilization, lactate production, stress hormone levels) are similarly related to exercise intensity in a curvilinear, rather than linear relationship. Finally, all these values are averaged, and the 4th root is taken.



If that all seems a bit complex, just think of adjusted power as the equivalent power you would have achieved if the race course had been perfectly flat and the pace perfectly steady, with no variations.



Two other metrics of workout performance, intensity factor (IF) and training stress score (TSS), are derived from normalized power, though space considerations preclude further discussion; the previously-mentioned CyclingPeaks Software includes all three of these features and has a nice explanatory article as well, at http://www.cyclingpeakssoftware.com/defined.html, while there is a free on-line calculator at http://www.virtusphysica.com/htmlspecialedition2003.htm.

"normalized" power is intended to measure metabolic cost.

OK. Seems like a good training tool for data analysis post event. but how is normalised power going to help during a race? I don't see the benefit above and beyond a HR monitor.

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"For longer races and race simulations, I'll always use a HR monitor rather than rely only on RPE, but RPE is pretty accurate for me."

All I can say to that statement is, I thought the exact same thing. Luckily for me, I raced with my powertap head and a rear disc--so I was still able to download the files. Without boring you to death with the numbers, I did some crunching on Analytic Cycling (yeah, I know I have too much free time) and figured that over my last 40km TT, I could have ridden about 2 minutes faster with the exact same average power-mid (52min vs. mid 54min), had I not ridden the first half WAY too fast.
The next 10 mile TT I did (with the tap and a wheel cover) was about 30 seconds faster than a previous 10 miler on the same course--with much worse fitness, and about 20 fewer watts.

As far as a power meter measuring the metabolic cost, unless your 'bad day' is the result of decreasing mechanical efficiency (I'm guessing this is pretty unlikely), a PM is exactly measuring the metabolic response, or the rate of demand on your muscles, by measuring force.
The only way the 'metabolic cost will be higher for a given power output' is if somehow you've become less efficient, or de-trained.

...or if you drank 12 beers the nite before :-)

OK. Seems like a good training tool for data analysis post event. but how is normalised power going to help during a race? I don't see the benefit above and beyond a HR monitor.

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The Ergomo shows normalized power in the display so you understand the impact of periods of higher effort real-time (like a climb in the middle of an IM bike leg).

http://www.bicyclepowermeters.com/Computer2.html

ergomo® Normalized Power (NP)

NP is calculated using a special formula that both smooths and weights your power output to better reflect the physiological (especially metabolic) “costs” of variable-intensity efforts. The value of NP is shown in watts. While competing in an criterium, for example, your average power might be 200 watts, whereas the NP is 250 watts because of the frequent high intensity sprints after each corner.

"The only way the 'metabolic cost will be higher for a given power output' is if somehow you've become less efficient, or de-trained."

Like if you are starting to come down with a cold, or were up all night tending a crying baby, or had bad sushi the night before, or ............ Any of that stuff impacts on performance.



Pretty impressive TT's. Were the courses flat or 'sporting'. re: your 40km TT, didn't HR show the same thing, i.e. that you went out way too hard???

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"Bad days" are usually caused by poor pacing...

Not specifically about normalized power, but there was an interesting study in which the subjects did a self-paced 40K TT, then did subsequent TTs wherein they went out (for a few minutes or more) either 15% above or 15% below their average power of the first TT, and self-selected effort thereafter. Their times for the 15% below TT were significantly better than the self-paced TT, and worse for the 15% (IIRC). Bottom line: power in a TT is very useful in ensuring optimal pacing.

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not necessarily. bad days could also be a result of some of the other things i've mentioned, or a heavy training phase, an undetected injury, whatever.

I guess what I'm saying is how much does a $1500 PM help your pacing during the race, as compared to a $50 HRM.

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Do you have a link to the study?

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Don't you guys think all of this analysis is way too much overkill for a bunch of MOP triathletes ? Seriously, I don't see times in ANY Olympic, half Ironman or Ironman races around North America getting ANY faster than 10, 15 or 20 years ago. The FOP and MOP is no quicker.

I agree that power based pacing is excellent, but people have been going fast forever on Perceived Exertion and Heartrate. This is likely more than sufficient for most MOP racers.

Bottom line is that your body is not the same every day. On bad days the PE is waaaaay hi for a given power output. This is your body's way of telling you that you might not be able to handle a given "power output" on that day. Perhaps cause you drank 12 beers the nite before or only got 2 hours of sleep :-). Sometimes you gotta listen to your body rather than the numbers :-)

...AND if you don't believe that PE works, ask Lothar Leder, first man to go sub 8 hours and he did it WITHOUT EVEN A WATCH...just by feel.

Looking. Here's an interesting one: http://www.ncbi.nlm.nih.gov/...83127&query_hl=4 "This strategy would be best monitored with 'power-measuring devices' rather than heart rate or subjective feelings as the sensitivity of these variables to small but meaningful changes in power during a race is low."

Sorry, couldn't find the link.

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