An Alternative Bike Pacing Strategy for a Hot and Humid IM
An Alternative Bike Pacing Strategy for a Hot and Humid IM
I am working to figure out what is the best bike pacing strategy for the potential of another Hot and Humid IMLOU. Ok what things come into play in laying out my bike execution plan.
· “No such thing as a strong bike followed by a bad run”.
· On a hot bike / run day it would help the run to come off the bike with a core body temp below the upper performance threshold.
· The Heat Index was 90 by 11 AM last year and continued to build on the bike.
· Smart bike execution says start slow and get your system stable and your nutrition plan in place.
· Even pace power execution on a steady temperature day is the most effective use of average watts.
· Power production levels fall as temperatures increase.
We have a issue that executing a even power strategy in the face of increasing temperatures will result in your core temperature being its absolute highest when you finish your bike and when you get to the real fun of the day – the run!
Here is what I have found so far about the impact of temperature on bike power generation and IM bike times (more research to do).
First we have the comparison of IM lOU bike times in the cool 2009 year ( avg temp on bike 67) and the hot 2010 year ( avg temp on bike 89). The curves below show a definite impact of the heat.
I have started down the path of analyzing the race database that we used to develop the EN Temperature Impacted Race Pace Predictor (TIRP). The impact of increasing temperature causing slower bike times definitely show up on a consistent basis. The added factor of wind impact that is complicating this analysis – so I’m not going to be done in the next week. So where else can we find temperature impact on cycling performance. I found multiple research papers where a 30 min self pace time trial was done in different temperature conditions. I consolidated the data points and created the following table and curve are the result. The challenge is how to translate 30 min TT impact data to a 5-7 hr IM bike ride????? One view is if your effective FTP decrease as the heat increases then to hold a constant IF level one would need to also lower the IF in direct relationship to the impact on FTP levels. Boy this seems to aggressive a reduction!
The next piece of info I have is my performance data in IM LOU 2010. My 2010 bike was faster than 2009 but this was due to an added 30 watts in FTP. I had done a RR prior to this ride at a solid 0. 75% IF and ran fine. So I felt confident that a .70 IF target would be conservative. Looking at the data below I see that the heat took its toll on my power levels and the final hour and a half the power levels fell off significantly. I had the fitness to ride beyond these power levels, I was well hydrated on the bike (peed 3 times) , so what happened? The impact of heat and humidity finally caught up with my core body temp.
I experienced this same dynamic this year in my second RR preparing for IMLOU. Started out strong and as the temps build the power levels came down. The last 12 min I was pushing to finish the ride by 5:12 and the best I could muster was an IF of .66 OUCH.
I step back and look at what information I have. There is no clear cut formula that will tell me how to pace another hot IM bike. But the idea that the true load to the body is the collective impact of the IF level you are riding and the temperature. As temp goes up your relative IF level needs to drop to keep relatively constant load to the body. To flip that around, one should push the IF levels higher in the cool of the day. Below is a proposal for my hot IMLOU pacing strategy. The thoughts built into it were as follows:
· Allow time at the front of the bike to get the system settled down and nutrition and hydration plan in place. But reduce the time due to the relative cool temperatures at this time.
· Press the power levels for the next 2.5 hrs before the heat builds
· As the heat of the day comes on factor down the power levels.
· Take the last 30 min to try and lower the core temp a degree or 2 to give more thermal capacity for the run.
To the right of this is the pacing strategy I would have run. Both of these end up with the same NP and IF overall they just get there in different ways.
If I was coming into a HOT IM and only had prior experience in cool to moderate conditions, I would take the IF I am confident I can hold and lower it by 2-3 % depending on how hot it is expected to be. I would then consider this dynamic pacing approach that says work when it is cool and survive as the heat builds.
A simple spreadsheet is attached that has the curves and table for your use.
All comments and suggestions are welcome.
Matt
0
Comments
Wow, this goes against the "uphill" wattage trend of a well paced IM EN recommends.
Hopefully some members who have successfully raced a HOT IM like this and felt like it was a good strategy.
Let's run it up the flagpole and see who salutes.
Matt - As you know, while I don't mind plunging into data analysis (that someone else has done!), I tend to cross check assumptions and findings against my own experience and findings.
I think a KEY point you make early on is the goal of keeping one's core temp below the magic number (which may be between 102 and 104 dpeending on the individual). I question whether a strategy of "starting slow" will help with that.
Given that the lowest temp will be at the start of the ride, and the highest temp will be at the end (unless you luck ot and ride into a thunderstorm - might happen!), it seems to me your data demonstrate the need to ease off as the day goes on. I think there are two key data elements which would enhance our understanding of this.
1. This may be one place where HR on the bike acutally has some value. The HR will probably reflect in some crude relationship the internal temp. If it's staying stable while watts go down, that's a good sign internal "central governor" mechanisms are operating to stay within the temp limit. If it's going up (even if the watts are going down) that may be a warning sign that one has not eased off enough to allow enhanced blood flow to the skin at the expense of muscles.
2. RPE is probably a good indicator as well. If you feel like you are working too hard, you probably are, even if your watts show you are within reasonable limits.
Finally, I'm again fascinated by the "S" shape of tghe curve, in particular the minimal effect temp seems to have for the very fastest bikers. This may reflect a number of factors. The fastest bikers are the most fit, most efficient, and can thus spare a little more blood flow to the skin to help cool. The increased fitness also is reflected in a lower core temp at the same IF (the definitnion of efficiency in this case). The faster speed means faster, better cooling due to increased wind "chill" effect (faster evaporation). There's probably not a lot the average AGer can do about any of that, so we're stuck in the middle of the "S".
I'll bet you discover that temp has little effect on performance below about 82F, and doesn't start to become meaningful for someone in the second quartile ("front of the MOP) until about 85-87F. 87F is the maximum temp the skin wants to be; higher than that, and it can't keep up with cooling needs.
I was doing some online shopping yesterday, as TriSports had a sale. I was looking for thin arm covers. I noticed there are several clothing items now available - arm warmers/coolers, compression pants, even tri-suits - which feature large pockets specifically advertised for cooling packs. No more jury-rigging, now it's official - ice packs in T1 and T2 are de rigueur.
I bet the most rigorous analysis - given the models we use - would be that which you suggest, a temperature correlation to FTP. However, since pacing effort is linear with FTP (i.e., done by percentage anyway), your stripped down approach should hold fine.
I am not surprised that the effect is smaller on more elite races either. I intuit (i.e., cannot prove, but assert) that there is not only a critical core temp, but there is a temp range below that at which the amount of time is a problem, .e.,g if 102 is a critical core temp, there is some "temp x time" that becomes a problem at 100 or 101. If so, similarly to TSS accumulation, where faster guys can go harder because they do it for less time, there will be less effect by heat on people that are out there for shorter periods.
...just speculation, but something to chew one. No idea how you'd model it.
@ Al I agree with your comment on the strategy of starting slow may not be the most advisable approach in these conditions. That is why I took out traditional 60 min just riding around warm up period and reduced it to 30 min and then ramped the power level up significantly in the early hours of the ride to take advantage of the cooler temperatures. I interperate this comment to say pick the be aggressive in the early hours strategy over the typical constant watts option 2. Is that a correct understanding? Second question, are you suggesting that I should be more aggressive than what I have proposed in the early hours?
@ William - you noted "I bet the most rigorous analysis - given the models we use - would be that which you suggest, a temperature correlation to FTP. However, since pacing effort is linear with FTP (i.e., done by percentage anyway), your stripped down approach should hold fine. " Thanks - those were my thoughts and the simplifed appoach is what I could execute given the time I had.
I have no intention of doing any math...but...I am also not suprised that the heat seems to effect the fastest folks the least. If you notice the truly fast [pro's and top AG folks] tend to have about the same times regardless of the weather or even the course. While farther back folks can have a huge delta based on things like weather/hilly v flat course it just not seem to matter nearly as much for the truly fast even when broken into percentages based on time. Not sure why that is but think it becomes an issue of you can only go so fast no matter how "easy" the conditions are and the truly fast are only slowed so much by no matter how "epic" the conditions get.
The trouble is that even though you'll be slowing down, your effort will still be the same/similar, so I'm not sure how much it's going to tire you out for the run. I'd have suggested practicing it in a RR, but there's no time for that now. What's most important is what do you have confidence in?
WWAD? I'm not familiar with the specific IM Lou course, but ... I would shorten the usual EN plan of JRA for 60-90 minutes to 30-45 minutes. Many IM courses I DO know - CDA, Wisc, AZ, Kona - all seem to have about 40-45 min of "admin" type riding out of T1 where settling in and passing/being passed by a lot of people just seems to flow naturally. After that, I would ride at the upper limits of an IF range which would give me 290 +/- TSS points for the ride if I kept it up the whole way. Then, as others above suggest, I would rely on RPE with HR back-up to let myself slow down as it got hotter.
AND, I would force feed calories and fluid a bit over my usual practice in the first 2-3 hours. For me, that would be 250 cal/hour instead of 200, and 1.5-2 bottles of fluid instead of 0.5-1. And I KNOW you'll be obsessively using all those cooling measures you've discovered.
I still think you'll ride into a thunderstorm, though. Be ready for some hydroplaning!
1. Could you compare the IMLP bike times for the year of the monsoon( or other colder day) to 2011, or other year with warm bike temps and validate the effect seen in the Kona comparison to minimize the tactics question?
2. Raced Augusta 70.3 in HOT 2009, and rain drenched 2010. Had a 15 minute PR in 2010 because the rainy bike kept us cool. Definite advantage both on the bike and run portion of the race.
3. Remembered the day Floyd Landis lit up the peleton in the TDF and was dumping cold water on his head nearly constantly during his climbs. Could have been the dope, but he was intent on cooling as he rode.
As well as adjusting pacing, should the strategy also include absolutely minimizing the effects of the heat, like ice packs, arm coolers, pouring lots of cold aid station water on the body, etc
This makes me think of Ricky Racer climbing that hill on race day...going hard early he pops his HR...and even when he's coasting down the other side of the hill at 0 watts, his HR is still in z4. Biking at 68% later in the day BUT with a z4 Heart Rate doesn't actually save you very much for the marathon.
I think what you see in the Kona files is the need to make the break...and once they are in it (or know the approximate outcome of the bike/race), they settle a bit.
I am debating this question as well with Kona coming up. As of right now, I am sold on the solid/steady pacing strategy (30-45' WU, then .72-.73 for most of the day). Around this I will work an aggressive cooling strategy, etc.
Given that we pace evrything from threshold data point, any time FTP or threshold run pace are lower, so should be the race effort relative to it.
This fact seems to be ignored by many out there, yet they cannot figure out how they could not hit their targets during race and walked the run.
Just my amateur 2 cents.
I'm now seriously thinking of how I can cool myself on the bike at IMWI, regardless of the temps. I know I do much, much better in cooler temps, I see it all the time with the climbing TT's and intervals I do every week. Will probably go with the Desoto tri bibs that arrived yesterday, as they have pockets in the thighs and one in the back. Will see how ice packs fit in there. At looking at the Lazer aerohelmets, with good ventilation and a hole in the top for pouring water on your head and will wear Desoto arm and head coolers.
I think you'll have trouble getting ice down the pockets on the thighs. They are fairly tight, and you have to stuff things pretty deep to avoid having them pop out. Also, experiment with the DeSoto head cooler in training (obvously). Maybe it was just perception, but I felt like I was cooler without it. But then, I can't run with any hat (even the skin cooler types) on without overheating.
Ride the EN Strategey with the idea of shortening your jra time. Living in Iowa and riding all summer in this heat(just like you) I would go with the EN method. I went on many a 3+ hour sunday ride and tried to pound out higher FTP in that heat and paid on the back end of the ride as it got even hotter. My best bricks came from the EN race method over the fast start and survive the finish. I am firmly in the middle of the MOP racers, you are in a different league, but I think a quality run is set up by a NIJA like bike effort.
AWESOME WORK!!!!
Thanks for putting this together and sharing it with the team!!!
I think you should do both: turn the watts down and use the cooling tricks. The hotter the race the less it's about racing and the more it's about attrition. Most of the field won't adjust things downward to account for the heat and will fall apart at the end.
Personally, I know it's tough to have an FTP and goal watts in mind and then have to turn them. Lately I've been dreaming of a magical place, filled with butterflies, unicorns, gumdrops and fresh legs, where my FTP will likely be about 10w higher than it is now = goal watts of X. I like that X. X = a very tasty bike split. But the hotter it is, the smarter it is to use all of the tricks, including turning it down on the bike AND cooling yourself whenever possible.
Yeah...they're pretty tight. But I'm sure I can figure something out with the pocket on the back + the singlet pocket. Hell, the waist of the bibs is pretty snug and I bet I could poor a ton of ice down there during the run....hmmm.....
I like the tri bibs and have worn them for everything except for LP this year. Was close to doing so which would have been sucky based on the swim and the heat. They are for sure warmer than shorts as there is more material and they go much higher. Much more comfortable to ride in though IMO. They never have bothered me running as much as I thought they would. Went fairly long in them in the half at Tupper Lake and for 5:30 plus at American Zofingen. One concern is that if you have to #2 they are going to be much harder to deal with as you would also have to take off your singlet. That was ultimately the reason I went with shorts although turned out to be a non factor. You certainly could put ice in that back pocket but when I have put ice in the desoto side pockets or the back pocket of a jersey it never seemed to make me feel any cooler. Ice on the head and cold sponges on the upper body have a much better effect.
I have read/been told that if you want to actually cool yourself down you need to do it in a place where there is a lot of blood circulating like your wrist or your neck. The small of your back will not do you much good. Also, while water on the head feels good I have read that it really will not lower your temp any. On your neck is better. To get around the areo helmet thing at LP I was taking bottles and squirting them down the front and back of my neck. Felt great. YMMV.
And when you say "ice packs" what do you mean by that? If LP is any guide paper cups with ice cubes and cold sponges is the best you are going to get.
I have not done much experimentation with the arm coolers that I have as it really has not been that warm while I have been riding but hear that they work better the wetter you can keep them.
MattS or others have talked about ice pack dealios that you can get at the drugstore. Crack them open or something to "activate" them and they get cold. That's about the best you can do on the bike, other than staying wet.
In my experience, the arm coolers work when you keep them wet. When you don't, on at long ride for example, they seem to be very, very light armwarmers in my opinion, though there is some benefit in keeping in keeping the sun off your arms (cancer has not been kind to my family. I need to start thinking about that stuff, though I wear SPF 1000 whenever I'm outside). But in a race, I can keep my body and my clothes as wet as I can get them, with 1+ bottles of water per aid station.
As for the head, things are different when you don't have hair. I always train with some form of bandana or Desoto head cooler, more for sweat reasons than anything else. Again, I figure dumping tons of water onto my head and a head cooler would keep the water on there longer to let it do it's thing.
20-25% of your blood flow at any given moment is going through your neck - your brain is a thirsty bugger! Sponges under shoulder straps is an easy way to reach close to those carotids and jugulars.
Ice down the shorts hits the femoral artery/vein, another high flow area. And have you ever noticed after a run how much you're sweating in the small of the back - don't ignore it.
TeamEN ShamWOW?
Thank you all for the feedback and input. I’m going to take the next couple days and refine the plan. Some comments have sparked some new ideas. I’m excited!
I can't really suggest a physiological phenomenon that is occurring that also takes it out of you at a muscular level, but I know that my muscles end up pretty darned fatigued on those efforts, even though I didn't reach the output level I'd planned.
So, maybe I'm saying that you can't separate the two so cleanly and say "my muscles are fine because they're not working that hard, it's just my core temp that's a problem".
Thought provoking... I don't really have a good thought process here yet.