16 miles done as 8 miles in the morning very slow and easy. 8 miles in the evening comfortable pace.
Brett asked a great question on yesterday's post and my response became so long I thought I would just post it...
Tim - a question on pacing. Take a highly aerobically fit person (you) and a relatively average aerobically fit person (me). At constant heart rate, what pace drift downwards might each one of us see during a marathon? Are you a fan of constant target pace as long as possible, or constant effort? Or is there so much grey area this question is impossible to answer?
Brett- Excellent question. I have looked closely at cardiac drift as my own fitness progresses and pay close attention to my athlete's HR progression (digression) during tests. When I am very fit my tests tend to stay even with HR vs. pace up to a certain point in mileage. I call this my "popping" point. If I do a MAF test for say- 5 miles- I see only a drop off of 2"-3" per mile. If I progress at MAF HR at a certain point the drop becomes very apparent- maybe 10"-15" per mile. This point, to me, represents where my endurance is by mileage. Remember that when I'm really fit my pace in MAF tests gets down to 5:30 pace. I think most MAF experts would say that I am not truly running at MAF HR, that I am running too intensely. Maybe. The MAF concept is not for runners though, it's for Ironman athletes. It has value to a runner at certain times of the year, but I would caution most runners to favor intensity that is based on their race time and intensity. My marathons take me ~2:30, not 9:00.. so the intensity is completely different and training needs to reflect the race goal. Plus the MAF formula has huge potential for error and should only be used as a starting point, then adjusted later based on the athlete's sense of their lactate threshold. Or get LT tested and use science. As I have said many times before- the MAF formula only coincidentally fit my own aerobic profile perfectly for the Ironman. Now though- when I am fit, my LT is ~178. MAF formula would have me running at ~135-145 HR.. at the low end I would be more than 40 beats below LT!! This is too moderate to build specific muscular strength required for me to run 5:30 pace in a marathon. Also, because in a marathon I can race up to a HR of 170, the disparity is too large. For Ironman on the other hand, the effort has got to be so moderate that the MAF principles tend to work more effectively. An ultra runner could use the MAF formula more readily. Or an athlete with a very weak aerobic profile that has problems burning fat even at slower paces. A MAF test can show this.
What I have observed in all 4 of my marathons is downward cardiac drift. At Denver I started at HR 170 and watched as it fell steadily to 155. This was more due to hypothermia (I suspect- I had numb lips, hands, and severely impaired judgement.. I was like I was DRUNK!) and a diet Rockstar energy drink at mile 20 brought me around enough to finish with a HR of 165. My pacing at Denver (as all of my marathons) was over zealous though, so part of the HR drop was due to muscle dysfunction. Also, a part of the HR drop has occurred at the moment that I gave up. I've given up in all of my marathons because at a certain point I looked at my watch and thought that the number didn't match my effort. The pace per mile triggered FEAR which allowed my brain (the central governor) to take control and protect my body (heart) from damaging itself. This is partly why I was always able to run the day after an Ironman- even the races where I ran a 2:50, I gave up during those races.
I believe firmly in training yourself to hold a certain pace, then on race day go for it. I used the HR monitor to guide my maximum intensity during the marathons but never actually ran by HR, mostly just goal pace (but I have always started my marathons well under goal pace, full of piss and vinegar! Too fast.). With the pace vs. effort concept, I think it depends on your goal. If you are going for a Boston qualifying time then you need to hit a certain pace per mile. I would tell anyone doing this, to run BQ pace as long as possible.. once you are within conceptual sight of the finish, then and only then, pick up the pace. If you are truly racing the marathon however and want to just run your best and find your limits, then effort is the way to go. For KC next week I will be running through the half in ~1:15 which (hopefully) will feel very easy. Running more on decaf tea. Then I will turn off my watch and run 100% by feel. Then the piss and vinegar. The course is quite hilly, the hilliest I've ever run but the strategy should set me up to examine my own problems with my central governor. "Problems" meaning that it is very strong.. my brain does not allow me to place myself in harms way. So in my case next week- I will be doing both pace and effort. No HR. As Uli says: "HR is wrong". And I now agree. HR is a guide that should be used with an open mind, something I've never really done. I allowed the HR monitor to tell me how I felt. I let pace tell me how I feel still, but am working towards correcting this by simply not looking at my watch. When I see a pace that I have learned is too fast to hold, then it triggers a fear response. Hormones are released and your legs go weak. I firmly believe that part of why the Kenyans have been so good is that they never learned fear of paces... they never HAD watches, or GPS or HR monitors... just a tree on a hill in the distance that they ran to with a group that included guys who have won NY, Boston, Chicago. They don't learn fear, they learn confidence.
Sort of a rambling response.. I'm not a writer. Jog hard.
ps- Uli, I'm sure you have some wisdom to impart here!