By the way, to answer my own question.. the difference in modelled time between the optimal modelled pacing strategy for a given TSS at LP that gives a VI of 1.02 (for an example set of rider assumptions), and that with a VI of 1.10 is about 1%.

And that takes a 5:30 bike split to 5:33 and change. Kona slots and AG wins have been lost by less than that. ;)

At which point it's worth worrying about...!

I was being sarcastic, of course, but I would be interested in your method for determining your result. The reason being that there are three alternatives for increasing the VI from 1.02 to 1.10:

1. Holding NP steady and dropping AP accordingly -- end result is a slower ride (assuming otherwise optimal pacing)
2. Holding AP steady and increasing NP accordingly -- end result is probably a similar speed/duration (again assuming otherwise optimal pacing), but a higher metabolic cost (if you buy into the NP construct)
   
3. Varying both AP and NP -- end result is hard to predict, but we can probably at least agree that this is a different animal than the original ride, both from a speed perspective and a metabolic cost perspective (again, depending on your view of the NP construct)

Assuming the first method, a simple calculation based off of an NP of 215 yields AP's of 210.78 (1.02 VI) and 195.45 (1.10 VI). Plugging these into the default values on analyticcycling (except for grade, for which I used 0%), I get 10.55 m/s for the 1.02 VI and 10.26 m/s for the 1.10 VI. That's a 2.75% difference, or just over a nine minute slowdown from a 5:30 split.

I agree, if your purpose is merely to finish, then nine minutes won't matter much. Still, I daresay there are plenty here and elsewhere in the world of IM triathletes who might not take them so lightly.

I also agree that monitoring TSS religiously in a race to the exclusion of other inputs (HR, RPE, speed, cadence, etc.) is not the right way to race. I doubt you'd find many folks who'd argue differently.

In the end, though, there are still literally hundreds of power files that demonstrate that most well-paced rides (defined as "rides followed by a solid run") fall within a narrow range of TSS values. Given that, along with the fact that there's enough variables out there on race day that can send your race into a downward spiral, I ask you: Why not use that range as a starting point? If it's too conservative, well, 26.2 miles is a long way to make up for riding too easy!

cramer

  

Cramer, great question, and one that really gets to the heart of the issue.

The example I gave constrained TSS, which within the range of times that we're talking about is pretty much the same as constraining NP, hence if I vary VI, AP will change... so it's effectively your case 1.

Now as you've modelled, if you reduce AP on a flat course, you go slower. And if you reduce AP while keeping VI constant on a hilly course you'll also go slower. However, your assumptions for option 2 aren't quite right.... on a hilly course, the optimal pacing for a constant AP, but increased NP (and hence increased VI) will result in a faster time. Why? Because the optimal pacing strategy can now allocate more power to the hills (where additional power counts), and less to the the descents (where it matters less).

So in case 1, you've got two opposing factors going on... an decreasing AP, which makes you slower, but an increasing VI which makes you quicker.

Now, the fact that the optimal strategy for a given hilly course results has a specific VI that's >1 and isn't infinte shows that neither one of these two factors always dominates the other..... ie there is optimum VI which balances those two factors.... And it tends to be quite low.. however, the reality is that within reasonable limits it doesn't make that much difference

So, Tim, let's take a hypothetical case. We'll call him Dan. :-) Dan has a FT of 240W. He's done a lot of long rides (>5 hours) and has power data for them. How would you instruct him to pace an IM bike leg? Or what workout(s) would you have him do to figure it out?
Dan

Tim,

Yes, in case #2 the rider will likely go faster -- however, at a higher metabolic cost. He/she could do that but the general feeling is that they're increasing their risk in a discipline where most people simply go too hard.

Since we're talking VI... The reason why you need to worry about it (to a certain degree) is because it's often indicative of a broader problem in your execution. I've had a ton of people send me their files and, interesting enough, what I often see with a high VI is also a high TSS. Of course, I then go into their power file and see something like 20 - 50 instances of where their power spiked for a period of >15sec over FTP. On some courses like IMWI, I'll see up to 80 instances. Again, it gets back to the point of how interrelated these metrics are. When we see a problem with one of them we often -- BUT NOT ALWAYS -- see problems with other metrics.

I also think if people would spend more time understanding what influences these metrics, there would be less debate. For example, "optimal" VIs for a given course terrain are modeled based on riding alone. The more people we have to pass on the bike course, the more variability. That will impact VI. It's not huge but it can easily have a .01 - .02 impact. There's nothing you can do about that other than be smart about how much power you apply as you pass people. People at the front of the pack always have an advantage here. But am I going to criticize someone because their VI was .02 high and they passed 200+ people when their TSS and other global metrics were in-line with their plan? Obviously not. Hell, even if they didn't pass 200+ I'm certainly not going quibble over .02 increase in VI.

It seems like so much of this debate is about trying to create a black or white situation out of something that is never black or white.

Cramer,

Regarding this statement:

"I also agree that monitoring TSS religiously in a race to the exclusion of other inputs (HR, RPE, speed, cadence, etc.) is not the right way to race."

Seriously, how would monitor TSS religiously in a race (assuming you have an Ergomo)? I don't even see it realistically achievable. What would you be doing? Checking your TSS every 5 - 10min? I'm beginning to have this visualization that someone would need to be staring at their PM for 112miles solid.

Maybe that's the problem? How do people visualize racing IM with a PM? I can tell that I look at my PM off and on for the first 10 - 15min just to make sure I'm settling in appropriately. Once I settle in I'm focusing on RPE in the flats. If I feel like I'm getting carried away in the flats then I'll peek down at my PM just to keep me honest. When I hit a climb I'll check my power and find my target. The first couple of climbs I might watch my power closely. Other than that I'll probably check my AP or (AP exclude zeros) at around the halfway mark. I primarily do it for peace of mind. If I follow my plan my AP is insignificant and I always follow my plan.

I probably spend way less time looking at my PM than I do coasting... ;-)

Thanks, Chris

Of course, I then go into their power file and see something like 20 - 50 instances of where their power spiked for a period of >15sec over FTP. On some courses like IMWI, I'll see up to 80 instances.

Of course, for someone like me that has a fairly pronounced inverted V power profile (despite training the vast majority of my time with long intervals), maybe spiking above FTP (& therefore more variable) isn't that bad?


edit: I look at my PM every couple of minutes - I mean, it's right there on my stem.

Chris,

I made that statement simply because it seems that there's a notion that that's part of the recommendation -- establish a TSS goal and monitor closely during the race to make sure you don't blow past it. That visualization you mention is, I think, what some others are seeing as well. Sometimes it's just necessary to state the obvious, in the interest of clarity.

cramer

No, it's not that bad which is why it's not a black or white situation. We have to evaluate these things and I've constantly stated that low variability is a characteristic that must/should be practiced during race prep if you're going to execute that way on race day.

If by "long interval" you mean riding ~5hrs with a low VI at ~75% of FTP then sure. Otherwise, I really don't think long intervals (eg 30 - 45min) have that much of an impact on helping those who have inverted V power profiles to learn to ride less variably. I know guys who are doing long intervals all of the time but they still hammer the hills way too hard.

Allow me to elaborate about the significance of watching your PM all of time. Bottom line, I believe that managing your power takes mental effort. Mental effort drains most people especially during long-endurance events. Clearly you should manage your power on race day but there's a line (fine line?) between micromanaging your power and just managing your power. I don't think micromanaging your power is effective. Where that line exists is probably different for everyone.

Thanks, Chris

Otherwise, I really don't think long intervals (eg 30 - 45min) have that much of an impact on helping those who have inverted V power profiles to learn to ride less variably. I know guys who are doing long intervals all of the time but they still hammer the hills way too hard.


Not quite what I meant. I know how to ride with a low VI, I was referring to trying to flatten my power curve.

Believe me, I understand. Maybe I wasn't clear. For example, I know how to ride with a high VI but it doesn't mean I'm completely comfortable doing it over 112miles. What I'm hearing is that you're really not comfortable doing it since comfort = power. Which goes back to the point of practicing during race prep.

I think it's important for every athlete focusing on TT or triathlon to ingrain or get comfortable executing that style of riding. You might find your power curve flattens as a result. Just my opinion...

Thanks, Chris

I think what El Fuser is saying is that since he has


that he likely has a *relatively* higher VO2max (as indicated by 5 min power) than LT (as indicated by FT power) despite trying to change this through training with longer intervals. The desired effect would be to flatten out the power profile by bringing the LT up to the same power profile level of the VO2max. Since this doesn't seemed to have happened for him he surmises


in effect, taking advantage of the higher power he has access to from his VO2max relative to his LT. Unfortunately, what dictates available energy for a discipline such as IM is the LT and not the VO2max, so, the higher VI approach will still dip into glycogen stores to the same extent based on FT/LT regardless of the relatively high VO2max.

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Steve

http://www.PeaksCoachingGroup.com

Maybe you can confirm but here's something I seem to experience with those who have high pVO2Max relative to FTP: They tend to ride quite variably throughout their training. IOW, they have this "high-VI" style ingrained. Bottom line, it's how they are most comfortable riding and their power curve is reflective of that fact. I can't really comment on El Fuser's claim that he spends a vast majority of time executing long intervals. Honestly, I don't know anyone who really spends a vast majority of their time executing intervals -- especially during race prep -- but it's a subjective term so who knows for sure. Personally, I don't and all of the people I train around don't seem to spend a vast majority of their time executing interval-style workouts during race prep.

Yes, your statement about dipping into glycogen stores is ONE fundamental principle behind the reason why I suggest a low VI for IM. Note that none of my guidance for IM execution stated in the past has ever referenced an interest in knowing the athlete's pVO2Max.

Thanks, Chris

Keep em tired enough and they don't ;)


Maybe. Of course, it's a broad generalization, but I think it's fairly typical for those with flatter power curves to be more comfortable with constant efforts. OTOH, those with steeper power curves are probably more comfortable with "bursty" efforts. So, I don't know if that's confirmation, but it's something I'd probably agree with. I guess the fact that I've proposed a 30/30 type of interval approach for sprinter types to "ease" them into constant efforts because they are more comfortable with variable efforts shows my cards, doesn't it?

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Steve

http://www.PeaksCoachingGroup.com

Yeah, instead of "confirmation" maybe I should have asked, "Do you share the same general observation?"

Funny how true this statement is:

"Keep em tired enough and they don't"

Thanks, Chris

Awesome! That was exactly what I meant.

Could you explain that last bit a little bit more? I understand what you are saying, but am unclear why you say "unfortunately". My thought is that I don't need to worry about the power spikes as much as the TT power curve people, since I've - in essence - got more matches to burn. In effect, it isn't going to cook my legs and ruin my run. Main application would be for 70.3 races.

Thanks.

edit: i.e. "optimal" VI might be different for people with different profiles?

and Paulo hits a home run: http://thetriathlonbook.blogspot.com/...s-for-triathlon.html

i.e. just use IF.

so simple. I miss you Paulo.

We aim to please.

RE: optimal VI. Optimal VI is dictated by the course. Whether that VI can be sustainable by the individual becomes the question. The available data shows the rate of glycogen utilization is related to LT/FT rather than VO2max. So, I said "unfortunately" because your strength apparently lies with your VO2max (or at least 5 min power) and your LT/FT is a *relative* (I don't know the numbers, so, it may be a strength compared to others) weakness. So, there really isn't much difference in glycogen utilization for one who has a proportionally higher VO2max (by 5 min power) when riding at a given IF. The IF dictates the rate of glycogen utilization. That being said, I think those who argue for a low VI are probably on the right track for most. Becasue the experience base for individuals for an IM is so low (you can only do one or a couple IMs per year), as the VI increases you're either 1) riding too slow on the easy parts or 2) pushing too hard on the hard parts. Since most will never gain the experience to know which is best for them, or how to strike the "optimal" balance, a more conservative approach may be best (conservative being low VI).

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Steve

http://www.PeaksCoachingGroup.com

Considering the profile of most IM courses, I wonder whether a low VI is an artifact.

IF and TSS are related. I don't understand why people talk like all of these metrics (TSS, FT, VI, IF) are independent. There are several ways to sneak up on similar conclusions about trying to approximate an appropriate biking level in an IM. What's all the fuss about?
Dan

Doesnt' that assume facts not in evidence?

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Steve

http://www.PeaksCoachingGroup.com

Paulo prefers football (American and otherwise)...so, maybe he scored a touchdown or a goal.

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Shawn
TORRE Consulting Services, LLC
http://www.TORREcs.com

I've seen "House" on TV.

Where do you think I learned to

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Steve

http://www.PeaksCoachingGroup.com