The Powermeter Thread

[CoachFergie]

Ugh, he rode a sub 4:30 112 mile time trial after swimming 2.4 miles in a little over an hour. Only 4 professionals were faster. Who cares whether his SRM was calibrated or not?

The SRM doesn't have an influence on performance but if you are going to claim he rode at an IF of .9 then calibration and zero offset is important.

I guess those of you who think that power number is more important than how fast you race.

Say we take a cyclist who was 6 sec behind the winner at Worlds one year and nearly 2min behind the next year (wonder what he did different???) you could compare the power between the two. If no changes then perhaps one had a more aero bike, a better position, rode the corners better or paced himself better.

 

[FrankDay]

The SRM doesn't have an influence on performance but if you are going to claim he rode at an IF of .9 then calibration and zero offset is important.

I am not claiming anything. That is what his training peaks data says.

 

[FrankDay]

Don't recall any studies showing knowledge of FTP or any threshold improving performance in any event.

Don't recall any studies showing use of a power meter for any purpose improving performance in any event.

 

[CoachFergie]

It is worth noting that Sam's swim was of such a time that he was given the opportunity to pass 950 other competitors over the course of his bike ride. The sling shot effect of all these passes is a rather significant benefit that the pros don't have the luxury to take. At 20 seconds per pass that works out to 5 hours worth of legal drafting time..........well that's got to be a GIGO value as well;} He certainly did not experience the same race as the pros.

A huge opportunity. On the track in Invercargill (indoors) I did a 2000m trial with an empty track and sat on ~300 watts recording a time of 2:55. When the warm up for the racing session was on I did another 2000m with about 50 others on the track riding round and for the same ~300 watts went 2:40.

Alex Simmons and others have shown that a single rider on the opposite side of the track creates a very small but measurable difference so in Kona having so many riders to pass would make a huge difference.

Omitting that sort of information is like claiming a rider used short cranks to go an hour faster in a recreational event and failing to mention the course was shorter, run in reverse and had different weather conditions. Fortunately I found another rider who raced and even though his power was down from the previous year his time was a lot faster as well.

 

[CoachFergie]

Don't recall any studies showing use of a power meter for any purpose improving performance in any event.

I concur. Glad we sorted that one

 

[FrankDay]

Alex Simmons and others have shown that a single rider on the opposite side of the track creates a very small but measurable difference so in Kona having so many riders to pass would make a huge difference.

Yes, especially with the typical 20-40 knot winds coming from the passing side going out (when you are passing all those riders). Winds were lighter this year but they always come from the side. Yes, very comparable to your experience on the track. LOL.

 

[CoachFergie]

I am not claiming anything. That is what his training peaks data says.

As Hugh says GIGO. I would suggest an IF of 0.9 for 4.5 hours is unlikely and means either the FTP is wrong (most likely) or the SRM is not calibrated or zeroed (less likely).

With several IF's that high from Kona seems likely that these riders need to do more work determining their FTP's. If they wish to use that information to plan their training loads and try and predict what power they should aim to sit on for the ride. Knowing that going out too hard can end in tears. But maybe (not being a Tri coach) the swim before and the having to run a Marathon after dampens the "start too hard" issue we see in Cycling Time Trials.

 

[FrankDay]

Alex Simmons and others have shown that a single rider on the opposite side of the track creates a very small but measurable difference so in Kona having so many riders to pass would make a huge difference.

Yes, such a huge opportunity. I think you can see the advantage here when early on in the ride he is going so much faster for so little power and then after he has passed everyone (he had passed about 90% of them in the first 90 minutes) the speed goes WAY down for the same power. Everyone should swim slow, such an advantage in this race.

 

[CoachFergie]

Unless everyone swims slow and you have no one ahead of you.

So even with the wind coming from the passing side he rode faster for the same power while passing people? And then when he had passed the bulk of riders slowed down for the same power?

 

[FrankDay]

Unless everyone swims slow and you have no one ahead of you.

So even with the wind coming from the passing side he rode faster for the same power while passing people? And then when he had passed the bulk of riders slowed down for the same power?

How much advantage do you see here? 30 minutes? Is there any advantage to the pros riding in a line 10-15 long 7 m apart? Care to quantify it?

 

[CoachFergie]

How much advantage do you see here? 30 minutes? Is there any advantage to the pros riding in a line 10-15 long 7 m apart? Care to quantify it?

No frigging idea, I don't coach Triathletes although when I did he won his age group at Kona.

Jim Martin did suggest at a recent webinar that the 25m a rider must sit behind in a cycling time trial still offers a level of drafting.

Once the new track is built in Cambridge I look forward to working with David Bowden (CyclenutNZ on ST) and the Alphamantis equipment to start looking at quantifying such things.

 

[FrankDay]

No frigging idea,

Yet earlier your wrote "A huge opportunity." You guys seem to need to object to anything that doesn't fit your bias. IF too high, FTP is wrong or PM not calibrated. Only explanation.

Anyhow, I am glad you posted that analysis done on ST as it really points out the real world problems when using this tool. Races are won by whomever gets from point A to point B the fastest. There is zero evidence that using a PM in any way helps the rider in maximizing their performance. It might be possible but what is done now is pretty fraught with problems.

 

[Alex Simmons/RST]

http://alex-cycle.blogspot.com.au/2013/02/pour-me-draft.html

 

[FrankDay]

http://alex-cycle.blogspot.com.au/2013/02/pour-me-draft.html

Interesting effort. A couple of questions. What did you mean when you said moderate winds. It isn't clear to me how you determined the benefit in a cross wind. Further, I presume this was a benefit when the riders were in-line riding at the same speed. I would presume the benefit would be less when the cyclists were not in-line for passing and the passing rider would be upwind.

But, assuming your data applies, it is clear that the pros (or anyone) riding in bunches at 12 meters in line for hours on end gather some benefit over riding alone, even in a cross-wind. It is not clear that a rider passing many people one after another upwind in a cross wind for an hour or two derives more benefit than that and one might argue the benefit should be less, being upwind. Do you have any thought on that?

 

[FrankDay]

One other issue I think you "naysayers" should address regarding Sam's data. One thing is incontrovertable, he rode 112 miles in just under 4 hours and 30 minutes and his training peaks data says he had an NP of 288 watts at an IF of .9. This would place his FTP at 320 watts. Now, if his IP is wrong then either his FTP has to be wrong or his NP has to be wrong. It we assume that for a 4.5 hour effort that the IP has to be about .75 then this would mean that, if his FTP is correct, his NP was really 240 watts or, if his NP was correct, his FTP was really 384 watts. One of these three has to be correct or something in between or he rode at an IF substantially above .75, perhaps even .9!

What would you expect to see as an NP for someone riding a 4.5 hour 112mile TT (albeit with a little drafting the first hour or so). I remember Steve Larsen telling me he used to aim for 280 watts and he rode a little faster than this but his aerodynamics were also superb (of course he also passed a thousand others before he saw clean air). So, 288 watts for a 4.5 hour effort for a less than Larsen-esque rider doesn't seem way out of line to me but what do you folks think? BTW, Faris Al-Sultan reportedly rode 290 Watts at a reported IP of .78 for an almost identical time as Sam. link to story here

 

[Alex Simmons/RST]

Assuming the power data is correct:

280W for 40km/h is certainly nothing particularly special aero wise. What was the wind like? I'd expect more speed for that level of power for a decent IM set up.

I'd also expect a 4.5 hour bike leg followed by a good run to be ridden at an IF of ~0.8, which would put his FTP in the 350-360W range.

But of course the power data may not be correct.

 

[FrankDay]

Assuming the power data is correct:

280W for 40km/h is certainly nothing particularly special aero wise. What was the wind like? I'd expect more speed for that level of power for a decent IM set up.

The winds were, reportedly, light for Kona (light for Kona may not be considered light everywhere else) but this, reportedly, made the humidity just awful. In town (where the winds are never anything like out on the course) it wasn't possible to walk short distances without sweating. I understand more than usual rode less than 9 and 10 hours but no one came close to course record on bike (except, perhaps, age-grouper Stefanie Adam who was about 5 minutes off). So, was the course fast or slow?

Kona is a unique racing environment and no two years are ever the same it seems.

 

[Alex Simmons/RST]

Interesting effort. A couple of questions. What did you mean when you said moderate winds. It isn't clear to me how you determined the benefit in a cross wind. Further, I presume this was a benefit when the riders were in-line riding at the same speed. I would presume the benefit would be less when the cyclists were not in-line for passing and the passing rider would be upwind.

But, assuming your data applies, it is clear that the pros (or anyone) riding in bunches at 12 meters in line for hours on end gather some benefit over riding alone, even in a cross-wind. It is not clear that a rider passing many people one after another upwind in a cross wind for an hour or two derives more benefit than that and one might argue the benefit should be less, being upwind. Do you have any thought on that?

Did you read Rob's notes on the wind (section in green text)?

The wind went from dead calm to moderate on the H interval. Distinct head, tail and cross winds on interval 3 (the H one), possibly more than what Moorabbin airport recorded as there was a rain shower that came through with much stronger wind.

He also posted the Moorabbin weather station data.

As explained in the post, I calculated the apparent CdA when leading compared with when drafting. The size of the drop in apparent CdA when in the drafting position was reduced in the cross winds compared with more benign wind conditions.

It's very clear what was tested, i.e. either leading or following at 12m behind lead rider's rear wheel. I did not assess passing manoeuvres.

But it stands to reason a rider passing, if they are smart, can gain great benefit for a large part of a passing manoeuvre. If there is a cross wind and they ride to leeward they can also gain great benefit. That is the fundamental basis of an echelon. Of course if they cannot ride to leeward, then they lose some benefit as they head windward on approach to the rider in front.

 

[CoachFergie]

Yet earlier your wrote "A huge opportunity." You guys seem to need to object to anything that doesn't fit your bias. IF too high, FTP is wrong or PM not calibrated. Only explanation.

You say the funniest things Frank. Yes, the word confirmation bias springs to mind!

As has been said GIGO. NP is calculated independent of FTP so no issues there and no one is denying that is a good power for any rider. Is it a good ride. Perhaps if he wore "lucky red socks" his power might have been higher. Without the big picture data we don't know. If he only uses his SRM in racing then you lose all of that. It can be estimated and the Wallace paper shows that TSS correlates with performance in a 1500m run better the HR or HRV.

I am not saying his FTP isn't set correctly but based on what many of us see looking at power files day in day out for years it seems it might be a bit out. Not out of this world to suggest that as one tapers the FTP in racing would be higher than the training FTP. Also that Sam trains on a Gimmickcrank exclusively would suggest he is missing opportunities to monitor his progress and fine tune his FTP.

Anyhow, I am glad you posted that analysis done on ST as it really points out the real world problems when using this tool. Races are won by whomever gets from point A to point B the fastest. There is zero evidence that using a PM in any way helps the rider in maximizing their performance. It might be possible but what is done now is pretty fraught with problems.

Well it would suggest that a few coaches need to be a little sharper with their setting of FTP. If you are going to use the power meter to pace off in the race or to calibrate your "feel" for race day. Many of my riders do this and we use the power to measure how well they did.

But to me the beauty of the power meter is quantifying training loads over a large time. I coach cyclists exclusively so all the riding is available to look at the performance manager to make training decisions. In conjunction with other metrics and forms of communication. The average powers for different durations and races gets a rider in the ballpark. The PMC tells me if they are going to happy at the finish or the one who cries at the end!

 

[CoachFergie]

I think you can see the advantage here when early on in the ride he is going so much faster for so little power and then after he has passed everyone (he had passed about 90% of them in the first 90 minutes) the speed goes WAY down for the same power.

So higher speed for given power while passing 90% of people in first 90mins.

Then after 90mins when not passing people his speed slows down for same power.

What does that tell you?

And of course this is an event based on three disciplines. Is there a prize for the fastest individual split?

 

[CoachFergie]

One other issue I think you "naysayers" should address regarding Sam's data. One thing is incontrovertable, he rode 112 miles in just under 4 hours and 30 minutes and his training peaks data says he had an NP of 288 watts at an IF of .9.

Well except the IF. That is questionable.

This would place his FTP at 320 watts.

Questionable.

Now, if his IP is wrong then either his FTP has to be wrong or his NP has to be wrong.

NP is calculated independent of FTP. Would also want to check if the SRM was calibrated and a zero offset was performed. Also when it was performed and if he did one mid ride. Not that the goal of Kona is to obtain power meter data.

It we assume that for a 4.5 hour effort that the IP has to be about .75 then this would mean that, if his FTP is correct, his NP was really 240 watts or, if his NP was correct, his FTP was really 384 watts. One of these three has to be correct or something in between or he rode at an IF substantially above .75, perhaps even .9!

Didn't Andy send you a copy of Racing and Training with a Power Meter. Read it. Making some pretty basic errors with power training metrics.

What would you expect to see as an NP for someone riding a 4.5 hour 112mile TT (albeit with a little drafting the first hour or so). I remember Steve Larsen telling me he used to aim for 280 watts and he rode a little faster than this but his aerodynamics were also superb (of course he also passed a thousand others before he saw clean air). So, 288 watts for a 4.5 hour effort for a less than Larsen-esque rider doesn't seem way out of line to me but what do you folks think? BTW, Faris Al-Sultan reportedly rode 290 Watts at a reported IP of .78 for an almost identical time as Sam.

Again, read the book. Might want to brush up on concepts like power to weight and power to frontal area.

 

[Alex Simmons/RST]

It doesn't surprise me that an IM athlete may not know their FTP, some quite possibly are not doing a lot of training at that level, nor specifically test for it.

They may construct a pacing strategy based on their long duration power, e.g. doing 100+ km TT efforts to base their training and race pace strategy on.

Specificity and all that jazz.

 

[CoachFergie]

It doesn't surprise me that an IM athlete may not know their FTP, some quite possibly are not doing a lot of training at that level, nor specifically test for it.

They may construct a pacing strategy based on their long duration power, e.g. doing 100+ km TT efforts to base their training and race pace strategy on.

Specificity and all that jazz.

True and if using estimated IF x duration to determine TSS for swimming and running to manage training loads then may as lump cycling in as well.

100km TT's

Have enough of an issue doing a 20min maximal test after a maximal 5min effort. Think I will stick to being a trackie!

Mind you knowing Scott Molina quite well I am sure wouldn't blink an eye at doing them.

 

[FrankDay]

It doesn't surprise me that an IM athlete may not know their FTP, some quite possibly are not doing a lot of training at that level, nor specifically test for it.

They may construct a pacing strategy based on their long duration power, e.g. doing 100+ km TT efforts to base their training and race pace strategy on.

Specificity and all that jazz.

I don't know how Sam has calculated or determined his FTP. However, he did say this to me when we met before the race. He said when he did shorter distances that his speed hardly changes at all. IM is his game. I suggested he might think about Ultraman and he said the problem was qualifying - no qualifying races that work for him. Hence, he seems, like me, to not own any fast twitch fibers. Maybe is IF is 0.9. Who knows.

Regardless of whether Sam's FTP in TP is correct or not Sam seems to race pretty well.

Another point I thought of last night. It has been pointed out that as an amateur and slow swimmer he receives a big boost due to the drafting he would see so, perhaps, he isn't as good as his time would indicate. However, a disadvantage he has is starting 30 minutes behind the pros. This mean the wind is coming up earlier in the course for him than it does for the pros. The amateurs see wind starting earlier and, usually, stronger winds than the pros.

 

[FrankDay]

Well except the IF. That is questionable.



Questionable.

Yes, everything is questionable to you. We know that.

Didn't Andy send you a copy of Racing and Training with a Power Meter.

No

Read it.

Why, what am I missing, science-wise? Without a science basis it may as well be a novel

Making some pretty basic errors with power training metrics.



Again, read the book. Might want to brush up on concepts like power to weight and power to frontal area.

power to weight? power to frontal area? what does that have to do with this discussion? Anyhow, Sam's power to weight was 3.7 w/kg while Faris Al-Sultan had a power to weight of 4.0 w/kg for an almost identical bike split. What does that tell you? Perhaps Faris would be better served working on his frontal area more than his power. Just saying … And, I was telling Sam I thought he could get more aero and squeeze some further speed out of his efforts. Maybe I will rethink that.