There's a mental component to performing in difficult conditions that can never be quantified in a calculator, imho. It's hard to tell which of us just ran well in the heat vs which of us have the ability to suffer more when we know it's going to be required. All of my IM runs in the heat were very difficult but then some of my IM runs in ideal conditions were very difficult too. I have never had the same IM run experience. Even if you just focus on my IM runs times that fall between 3:30 - 3:39 (8 of the 14), some of those days I "had it" and some of those days I didn't. The races where I didn't have it I just had to dig deeper. I suspect most people might just look at those race results and feel that I had the same relative experience in all 8. It's just too hard to tell if the real hot days (IMCDA '06 and IMC '11) were days where I had it but had to dig deep in order to make it look easy. Or maybe they were days where I didn't really have it so the heat really didn't impact me. My honest opinion is that I had it at IMCDA '06 but didn't have it at IMC this year. Same result and I felt I had to dig deep in both of those runs.
It's funny because I consider my best IM performances to be the ones where I suffered the most, not the ones that necessarily produced the fastest times. My 9:41 (PR) at IMAZ was one of my least memorable IMs. All I know is that I enjoy running in the heat a lot more than I enjoy running in the cold.
I used the tool for IMWI 2011. It was a big help. I don't have to use tables and graphs anymore. But what I wasn't ready for was the elevation change. I averaged 9:26 pace for IMWI, but my NPG was 8:44. If we throw in some accomodation for elevation changes the tool would be even more accurate. This should an easy fix relative to what's already been done. Incidentally it was reassuring to see that what I came up with to adjust my pace from 5K Vdot to IM run pace was the same, but Matt's tool is much quicker and user friendly.
Is it still pretty accurrate to use this tool for a stand alone marathon? 12/3/11 I am running a marathon in Jamaica. We start at 0515 d/t the rising heat and humidity throughout the day. 2 years ago I did this in 4:02. Using the TIRP and plugging in the heat and humidity it has adjusted my best finishing time around 4:30. I wasn't sure if this tool was more accurate running a mari off the bike or the same for stand alone marathons.
I'll defer to Matt S. and others, but if it's a standalone marathon, I'd suggest looking at Jack Daniels' "guidelines" for temperature impact (which you can explore using this spreadsheet: http://www.electricblues.com/archiv...-00-00.xls ) - specifically the "Projected Adverse Impact of High Temperatures" section.
TIRP is definitely IM marathon specific and "incorporates" (by virtue of the dataset that was used to create it) things like thermal load over the course of a long day, etc., etc. - issues that aren't as important in a standalone marathon.
This tool uses degradation curves which are derived from IM marathon data. Specifically, the actual marathon times from almost all North American IMs of the last decade were correlated to the hour-by-hour race day temperature and humidity. It is not intended for use in standalone marathons. A key difference is that, in a standalone mary, one is starting from a well-hydrated, well-fueled state. In an IM, one is of necessity at least a little dehydrated and behind on calories at the start of the marathon. So the effect of heat in an IM may be greater than in a standalone marathon, for a given VDOT.
@ Carl - The summary answer – Do not use TIRP to estimate the heat impact on straight marathon pacing.
The complicated answer -
Al is correct that temperature will have a bigger impact on an IM marathon than a straight marathon. You just got off a 5-7 hr bike and the body core temperature will be significantly hotter when you start the IM run than when you start a straight marathon. In very hot conditions like IM Lou in 2010 or Kona your core temp could be close to the 104 shutdown level.
So say your core is at 103 off of the bike and now you start a run in >85 degree temperatures, compare this to starting a marathon at a core temp of 98.6 Your body has a huge difference in the amount of energy it can create above what it can eliminate by all cooling means before your core hits the shut down point of 104. This directly translates to the ability to run faster for longer in a marathon than in an IM run.
The starting point for TIRP was a study I found that focused on the heat impact on marathon times.
TITLE: Impact of Weather on Marathon-Running Performance
SOURCE: Medicine and Science in Sports and Exercise 39 no3 Mr
2007.
To give some numbers to thisdiscussion, below is a key chart from the study I referenced above. They looked at marathon times up to 3 hrs and a max temp of 25C or 77 F
Notice how as the temp goes up and the time you are on the course increases you get an increasing rate of performance impact! So at 3hrs and 77F you get a 12 % performance hit. If we go into the denials’ vDOT table we get a vDOT of 53.5 for a 3 hr marathon. If we drop that into TIRP we get a 7% pace impact??
So what up with a 7% TIRP vs 12 % from the paper. You need to remember that this is all based on the record runs. Record marathons are in the ~2:05 – 2:08 range and record IM runs are in the 2:40 to 2:46 range. This is a ~ 20% difference between paces that form the anchor for the charts. So add the 20% +7% from TIRP and you get a 27% impact.
To try to clarify, if you have a vdot 53.5 and can run a 3:00 marathon at 60 degrees you will run 12 % slower at 77 degrees or a 3:21 marathon.
With that same vdot in the EN pace chart which is used in TIRP, the best IM you will run is 3:32 at 60 F. This pace is 17% slower than your straight marathon pace. Now from TIRP at 77 degrees and you will run ~3:49 which is 27% slower than your straight marathon pace at 60 degrees.
@ Craig, I use the same Jack Daniels' table you referenced above. If you look at his math he is using a straight 2% impact on pace for each added 5 degrees in temperature. For races up to a 10K or maybe a ½ mary if you are fast that likely will work but for a marathon the chart above says the impact is not a straight line with temp. To estimate my heat impacted marathon pace, I would use the chart above and draw the curves out to a longer time if needed.
I tried to add the full pdf to this post but it is above the file size limit. If you want a copy PM me I will email it to you.
Matt - The FAQ's refer to HIM guidance "coming soon". Has that happened yet? If so, and I missed it, I apologize. Would be especially helpful for this weekend's races when we have been training in cold, and race day looks HOT. Thanks
Matt - The FAQ's refer to HIM guidance "coming soon". Has that happened yet? If so, and I missed it, I apologize. Would be especially helpful for this weekend's races when we have been training in cold, and race day looks HOT. Thanks
John, Sorry - the HIM quidance has not yet come together. Best of execution on your race.
HIM WARM RUN DOUBT: is there a "simple rule of thumb" to adjust run pacing for HIM on a warmer than expected day? Found a lot of info on wiki for IM not HIM.
HIM WARM RUN DOUBT: is there a "simple rule of thumb" to adjust run pacing for HIM on a warmer than expected day? Found a lot of info on wiki for IM not HIM.
This is a total guess on my part; I have absolutely NO data OR experience to back it up ... Run the EN heat pace calculator with thetemp and dew point and your VDOT. Then note the percentage increase in time for that combo (NOT the actual pace). Then apply that % increase to your own pace. That should at least give you a ball park to start playing around in for a given temperature. But again, those numbers are derived from actual IM races, not HIM, so we just don't know for sure.
@Al, tks much for yout input. I runned the numbers as you suggested and the outcome is a 17% increase. Given that number, I wonder if and how to adjust to HIM? Looking at the EN Pace Chart HIM, for my Vdot (49), best possible time would be 1:36:56 + 17% that´s in the 1:53:30 neighborghood (versus 1:43:42 @ 88% pace). What is your opinion of a further total guess and take half of the 17% increase? (or 1:44:16) .... or better to be conservative and take the full 17%???
Just wondering if anyone has worked this out for a Half IM yet. I competed in the Bone Island Tri last weekend, in 81-84 degree temperatures, having gone down to Florida from the snowy north. I was disappointed in my run, but it could be considered better than expected if I use the Full IM TIRP.
Just wondering if anyone has worked this out for a Half IM yet. I competed in the Bone Island Tri last weekend, in 81-84 degree temperatures, having gone down to Florida from the snowy north. I was disappointed in my run, but it could be considered better than expected if I use the Full IM TIRP.
Nope. And I really doubt there's any kind of meaningful correlation. People tend to start falling apart in an IM between 11 and 16 miles, suggesting that 13 miles may not be quite long enough for excess heat build up in the core to impact times to the degree it does in the longer distance. That said, I'm sure there must be some degree of slowdown required when racing in the low 80s compared to the upper 50s.
@Kate — in addition to WSM Al Truscott's reply, I would have thought that using heart rate could help you adjust your run pace. Of course, this assumes you know what your typical HIM run pace heart rate is (through race rehersals etc).
Peter's right on in focusing on the real question - "How should I adjust my race pace when the temp goes up in an HIM?". Coach P has given some good advice on how to use HR in an IM to adjust pacing. The thread should be somewhere in Race Exdecution or Power and Pace forum? General iea has to do with monitoring your HR at the end of a well-paced bike leg, then using that to set your HR for the run. This was about an IM, but same principle might apply to HIM? There was some discussion about exactly what the proper HR level should be Zone 1 vs 2. So for and HIM , my opinion owld be keeping the HR in Z2 woud be the approach, others may differ with that.
IOW, don;'t follow your pace at all, race to an HR target. And there are some of us who are hooked on using RPE as a metric on race day, but that requires some experience nati racing the distance, and in various environmental conditions.
N=1 info here. A couple weeks ago, I did the Ragnar Relay, Miami to Key West. My first leg was ran around 2:00pm and heat index was 90 degrees. My Hr at 9:40 pace was about what it would have been at 8:30 pace for the 8 mile leg if I had been running back in NC in 50 degree weather. After I hit 165bpm, I just conceded that my target pace of 8:30 wasn't going to happen with the heat. So, if my math works out that is roughly 15% slower. It was a shock to the system due to a total lack of heat conditioning. Did much better on the night legs and much shorter leg the next afternoon.
@Kate, for my last HIM (Miami) I runned the TIRP calculator and adjusted pace by 50% of the suggested TIRP adjustment (it said reduce calculated pace by 15%, I reduced 7.5%) plus monitored "heat" via HR max of 145bpm as suggested by CoachP. It was my best HM run ever.
Sometime in the next 5-10 years, we're going to be swallowing little "pills" which are actually ANT + transmitting thermometers, and reading our core temp on our wrist/Garmin.
I'm dead serious; this technology already exists and has been used for quite some time in studies of heat exhaustion in football players and endurance athletes.
We'll be watching that we don't go over 39C or 102F, just like we've monitored our pace for the past decade and HR for the past two. Then who knows what's next - constant monitoring of blood sugar to help with nutrition?
Comments
It's funny because I consider my best IM performances to be the ones where I suffered the most, not the ones that necessarily produced the fastest times. My 9:41 (PR) at IMAZ was one of my least memorable IMs. All I know is that I enjoy running in the heat a lot more than I enjoy running in the cold.
Thanks
I'll defer to Matt S. and others, but if it's a standalone marathon, I'd suggest looking at Jack Daniels' "guidelines" for temperature impact (which you can explore using this spreadsheet: http://www.electricblues.com/archiv...-00-00.xls ) - specifically the "Projected Adverse Impact of High Temperatures" section.
This tool uses degradation curves which are derived from IM marathon data. Specifically, the actual marathon times from almost all North American IMs of the last decade were correlated to the hour-by-hour race day temperature and humidity. It is not intended for use in standalone marathons. A key difference is that, in a standalone mary, one is starting from a well-hydrated, well-fueled state. In an IM, one is of necessity at least a little dehydrated and behind on calories at the start of the marathon. So the effect of heat in an IM may be greater than in a standalone marathon, for a given VDOT.
@ Carl - The summary answer – Do not use TIRP to estimate the heat impact on straight marathon pacing.
John, Sorry - the HIM quidance has not yet come together. Best of execution on your race.
This is a total guess on my part; I have absolutely NO data OR experience to back it up ... Run the EN heat pace calculator with thetemp and dew point and your VDOT. Then note the percentage increase in time for that combo (NOT the actual pace). Then apply that % increase to your own pace. That should at least give you a ball park to start playing around in for a given temperature. But again, those numbers are derived from actual IM races, not HIM, so we just don't know for sure.
@Al, tks much for yout input. I runned the numbers as you suggested and the outcome is a 17% increase. Given that number, I wonder if and how to adjust to HIM? Looking at the EN Pace Chart HIM, for my Vdot (49), best possible time would be 1:36:56 + 17% that´s in the 1:53:30 neighborghood (versus 1:43:42 @ 88% pace). What is your opinion of a further total guess and take half of the 17% increase? (or 1:44:16) .... or better to be conservative and take the full 17%???
Just wondering if anyone has worked this out for a Half IM yet. I competed in the Bone Island Tri last weekend, in 81-84 degree temperatures, having gone down to Florida from the snowy north. I was disappointed in my run, but it could be considered better than expected if I use the Full IM TIRP.
Nope. And I really doubt there's any kind of meaningful correlation. People tend to start falling apart in an IM between 11 and 16 miles, suggesting that 13 miles may not be quite long enough for excess heat build up in the core to impact times to the degree it does in the longer distance. That said, I'm sure there must be some degree of slowdown required when racing in the low 80s compared to the upper 50s.
Of course, this assumes you know what your typical HIM run pace heart rate is (through race rehersals etc).
Peter's right on in focusing on the real question - "How should I adjust my race pace when the temp goes up in an HIM?". Coach P has given some good advice on how to use HR in an IM to adjust pacing. The thread should be somewhere in Race Exdecution or Power and Pace forum? General iea has to do with monitoring your HR at the end of a well-paced bike leg, then using that to set your HR for the run. This was about an IM, but same principle might apply to HIM? There was some discussion about exactly what the proper HR level should be Zone 1 vs 2. So for and HIM , my opinion owld be keeping the HR in Z2 woud be the approach, others may differ with that.
IOW, don;'t follow your pace at all, race to an HR target. And there are some of us who are hooked on using RPE as a metric on race day, but that requires some experience nati racing the distance, and in various environmental conditions.
@Kate, for my last HIM (Miami) I runned the TIRP calculator and adjusted pace by 50% of the suggested TIRP adjustment (it said reduce calculated pace by 15%, I reduced 7.5%) plus monitored "heat" via HR max of 145bpm as suggested by CoachP. It was my best HM run ever.
Sometime in the next 5-10 years, we're going to be swallowing little "pills" which are actually ANT + transmitting thermometers, and reading our core temp on our wrist/Garmin.
I'm dead serious; this technology already exists and has been used for quite some time in studies of heat exhaustion in football players and endurance athletes.
We'll be watching that we don't go over 39C or 102F, just like we've monitored our pace for the past decade and HR for the past two. Then who knows what's next - constant monitoring of blood sugar to help with nutrition?