I was wondering how long it would take for this to make it to ST. I'd be interested to hear what Rich Strauss and Lakerfan have to say about this.

Regardless of if they give their thoughts, I know which side I'd be on...

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"What the mind can conceive and believe, the mind and body can achieve; and those who stay will be champions."

Lakerfan threw his toys out of his pram and left a while back

Which side is that? Genuine question.

Paulo's blog makes sense, and I'm certainly not the coach or athlete that has room to be really arguing this in depth, but it seems like he is very good at shooting down the methods of others but doesn't really talk much about what his own methods are. He is quite a successful coach, but I'm interested in what it is that makes him so successful. Maybe I'm just not reading between the lines well enough.

His point is simple: there's a body of evidence that supports something like the 5% reduction in intensity for a doubling of time, and a constant TSS approach doesn't follow that curve. This leads to mis-pacing unless you are at the exact duration (a single point) where it would be correct.

There is a great post somewhere on ST where someone has calculated the curves for bike pacing IF + run pacing IF, with total race duration factored in to trade off bike pacing vs. run pacing to improve overall time. This would be one alternative approach.

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Note to self: increase training load.

What "body of evidence" is that? AFAIK that's just a rule-of-thumb that Joe Friel proposed when he himself was still learning about how to best use a powermeter.

I understood clearly what Paulo was saying. Your reply doesn't address anything that I was asking particularly. Were you intending it for me?

My question is does he have a better suggested method? Does he care to share it? It's easy to fire shots at anyone else's method, it's much more difficult to clearly and concisely share your own body of work and knowledge.

What does the evidence show the relationship to be? I keep meaning to ask how the TSS equation came about.

Okay, having now read Paulo's blog entry, it seems to me that:

1) he's operating on certain underemphasized/possibly incorrect assumptions, i.e.,:

"...let’s say that there is an exponential relation between duration and IF. In order to “anchor” this curve, the upper end is obviously FTP (1,1). The other point that defines the curve can be a common intensity estimator for maximum efforts lasting 2 hours – IF=0.95 (2,0.95)."

and that

"...there will be an intensity above all running off the bike at a pace according to your running specific level of fitness will be impossible. That intensity threshold should be somewhere between 90 and 95% of the maximum effort for a given duration."


despite which

2) he's still quibbling over relatively small differences. Specifically, based on his assumptions the appropriate IF for a 4:30 IM bike leg is 0.77 to 0.80, whereas one based on a TSS budget of 265-290 is 0.75 to 0.79. For a 6:00 IM bike leg, he comes up with 0.70 to 0.74, vs. a Whyte/Strauss/Ashburn recommendation of 0.66 to 0.69. Now it would be nice to think that people could "titrate" their effort that closely (especially w/o access to normalized power, etc., during the event), but the reality is that between the inability to do so and the need to adjust "on the fly" for race day conditions, the above guidelines are practically equivalent.

Still, nice to see that the TSS budget approach has caught Paolo's attention...it may not be perfect, but conceptually I think it has a lot going for it, and my hat's off to the Endurance Nation folks who have pursued this concept.

   
Seems to me that it doesn't matter if you use TSS, heart rate, pe, pace or whatever. All these methods are only meant to keep you honest with what you know you are capable of from training with one of these methods so that you do not go to easy or to hard. The argument between the various methods has always seemed to be the variability of the method, for example, heart rate drift over the course of an IM or pe seems harder than it really is. The argument for TSS is that iy isn't as variable as heart rate. That may not be true or it may be. I prefer heart rate myself and despite drift it seems like a good indicator of desired pacing.

From a couple posts in the power forum at Endurance Nation. As background, the subject of many of our recent discussions over there is how do we do a better job of creating better races for our athletes who are coming off the bike north of about 6:45? At present we are focused on refining our run pacing guidance. Paulo's article suggests additional refinements that could be made to the bike pacing we recommend to these folks as well.

{snip}

Thanks for sharing the article. Good to see Paulo sharing his knowledge. Obviously, the EN power kit and our guidance is the "target" of this article and I believe he has many valid points, several of which I have not considered. A few quick notes:

"Some approaches to the determination of correctly paced ironman bike rides use TSS as an effort budget. Like it was mentioned above, this does not make much sense, since using TSS as an effort budget goes beyond the scope of the definition, not to mention not being supported by any kind of evidence"

We have the evidence, we just haven't shared it with him. And, no, it's not anything that would stand up to scientific inquiry, which might be the standard he's looking for. My power webinar partners and I looked at a lot of race files, race data, and simply saw that people coming off the bike with TSS scores of 280-290 had better runs than people who came off north of 300.

As I read his article, it appears he is saying that our table with a range of "good" TSS'es and resultant IF's was determined by drawing a straight line, resulting in IF's that are too hot under 5hrs and too cold over about 6-6:30hrs. He feels this line should be curved. He has a very good point here, one that I never considered. A couple points:

• A LOT of people fit within this 5-6:30 time range.
• Actually, to be fair, I think he talks about 6hrs as the point at which our model starts to be come ify. I'd say that my sense, based on the experiences we've had recently, is that this line is about 6:30.
• Hopefully you've seen from our racing with pace discussions after CDA that we are searching for an answer to this problem through proper run pacing. Paulo's article now offers us another way to approach this, by tweaking our bike pacing guidance.

I suspect that me, Patrick, Chris Whyte, Jason Digman, and Rick Ashburn will put our heads together and see if there is a need to update the guidance in our power webinar.

+++++++++++++

...and what Steve said about the data set. That's the set where we got our data: 5-6:15'ish bike splits. No surprise, as that's where a very large percentage of the field is riding. In addition, you're not going to find many athletes out there riding 7hr bikes with PM's.

However, discussions like this can be a slippery slope, as they, by their nature, separate bike pacing from run pacing. Focus us on a bike split vs an over all time. So, someone uses our guidance, rides "too easily" comes off the bike with a time slower than they probably should have...but still ends up walking much of the marathon. What happened? Where is the knowledge and execution gap?

More importantly, what knowledge gap resulted in the largest loss of time on race day? A gap that produced a bike split 10-15' slower than they could have ridden? Or the knowledge gap that resulted in giving up 1:30+ on the run?

Which problem should we try to fix first?

Can we solve the first problem for everyone by having them focus on the big picture execution stuff first, our Four Keys?

At the watts, CDA, etc required to ride a 7hr bike split, what is the wattage difference, and the resultant speed difference, between IF .70 and IF .67? What kind of race do we get when we combined .7 with incomplete run pacing guidance? What race do we get when we combine .67 with spot on run pacing guidance? My strong, strong feeling is that it's better for these athletes to run 26 miles at the 11' miles their training has demonstrated they can do, than to get off the bike, wing it, run 10-10:30 for 10 miles, 13' through 15, then walk 11 miles. We owe it to them to fix THAT problem first, before we hem and haw over 10-15' on the bike.

The reason why Patrick and I are writing a series of articles on our blog and on Xtri to explain our system of IM pacing is because it's just that: a system that gives equal parts importance to your head, power on the bike, and pace on the run. You need to look at all three parts, not just one.

Having said that, I say again that Paulo's article, I feel, has pointed to a refinement of our pacing guidance for >~6:30 IM bikes. And we will work on that, but it will ultimately be presented within a system that applies head stuff on the front end and pace stuff on the back end of that bike pacing.

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Rich Strauss
Endurance Nation Ironman 2013 and 2014 World Champion TriClub, Div I
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As Paulo hypothesized, the terminal slope of the intensity-duration relationship can usually be reasonably well-described by an exponential function. Friel's rule-of-thumb approximates that, but 1) it's quite a stretch to say that it's based on "a body of evidence" and 2) -5%/doubling isn't steep enough except perhaps for the most fatigue resistant.


Oh, that's easy: since it's clear that duration and intensity interact in some manner, but we don't know precisely how, I took the parsimonious approach of simply multiplying them together. The fact that TSS ends up being weighted as a function of intensity^2, rather than just intensity^1, is a chance consequence of then expressing things relative to the individual's own ability (i.e., their functional threshold power). As it turns out, TSS scales with intensity almost exactly in parallel to Foster's session RPE approach (see slide 29 of http://www.cyclecoach.com/...gload/uksport1.ppt), but that wasn't my intent...sometimes you just get lucky. :-)

I'm not sure I agree with that.... taking the top end of the 6 hour leg, Strauss would have a limit for a 270W FTP of 186W, while Paulo would have one of 200W... those are totally different effort levels, and would result in very different times (something like 15mins+. EN would certainly have you believe that you can and should titrate that effort in that way.

I grant you that it's a battle of assumptions on what the budget is and how its calculated though...

I am also interested in the body of evidence, George Dallam's new book uses this idea as a key aspect of setting up the training program. He does a little math and you find the % drop for every doubling of the distance but it's a very similar idea. It being a mass market book he just makes the assertion and doesn't give any research to back it up, so I've been intrigued on where this came from.

I think it would be great if you shared the evidence.... this 280-290 TSS is becoming a bit of a mantra, with little to back it up.

Try this:

http://www.cyclecoach.com/...ingload/uksport1.ppt

or typye

http://www.cyclecoach.com/...ingload/uksport1.ppt

into your browser.

wow, that whole post went right over my head...

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maybe she's born with it, maybe it's chlorine
If you're injured and need some sympathy, PM me and I'm very happy to write back.
disclaimer: PhD not MD

Got it, thanks.

I'm not one to quote or dig up research, but if you take Daniels' prediction tables and convert them to power they roughly equate to this 5% rule. I think Daniels actually generated them from empirical data, using a the rate of oxygen utilization from a large number of runners. Apologies for implying there's a "body of evidence" when that's only an assumption on my part, given that I've seen this concept used in multiple disciplines.

By the way, since you responded: where did your 5% rule for estimating LT from the 20 min test come from? (This isn't a snipe, it's a real question, since I was under the impression this was generated based on a concept similar to the 5% rule.)

And as an aside, I'm not completely against using TSS as a factor in pacing since it's a rough guess as to the energy utilization for a given ride. Using training data from comparable rides to guide an acceptable TSS for the race distance doesn't seem inappropriate.

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Note to self: increase training load.

...which would fit with my comment re. the fact that most people's ability to maintain exercise intensity falls off more rapidly than -5%/doubling in duration (since most people consider Daniel's tables to be overly ambitious).


That's not my rule-of-thumb, it's Hunter's. Personally, I figure that if you're going to go to the trouble of doing a formal test, why settle for an estimate that is no more accurate than what can be obtained using other, easier means?

it seems like he is very good at shooting down the methods of others but doesn't really talk much about what his own methods are

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Did you miss this?

"I would suggest that if we’re looking for a realiable effort budget, the actual work being performed for a given duration needs to come into play. But this is hardly a new concept. "

I didn't miss this. How exactly would he suggest examining the actual work being done and implement this into a pacing strategy? Is this not what Rich and Patrick are trying to do?

I'm not trying to criticize Paulo, I'm trying to understand what his suggested alternative solution is to what he describes as a flawed pacing strategy.