Monday, June 29, 2009

HIT vs ET: A Scientific Review

Sometime late last week, my partner-in-running-crime Frayed Laces, asked me to review her latest running science report on the benefit of long endurance training vs short interval workouts in increasing aerobic capacity. Since I am a passionate runner, a medical scientist and somewhat of an Alberto Salazar to her Kara Goucher (okay the last one is a bit of a stretch, but work with me here people…) I will oblige her request and share with you all my scientific opinions on her piece.

For all who haven’t done so, please read my review on the physiologic differences of interval training, tempo workouts, and long runs because what is to follow will be somewhat of a continuation on that theme. First of all, let me start by saying that I agree with FL’s general assessment of the NY Time’s report. The physiologic benefit of HIT (high intensity training) vs ET (endurance training) is oversimplified in their review. On the protein level, the rise in PGC-1a seems rather short after HIT compared to ET. The peak levels (as she has shown) is indeed lower as well, even if the difference may not be statistically different. It is also impossible to extrapolate the changes in concentration of one protein level as the cause/effect of training as we know that it is sometimes not the quantitative effect but a qualitative effect on protein-protein interaction that affects muscle performance.

On the macroscopic level, I surmise that HIT/ET produces some qualitative differences on running economy that may be not measured in their simple rat/human experiments. As I explained in my initial review, I surmise that HIT is similar to going at max speed for a short time, while ET allows the oxygen delivery system to become more adapt at sustaining top efficiency for a much longer period. In the span of a 30-minute test or some other short-term measure, both parties can have similar benefits but if you extended the test and asked the subjects to bike/workout at equivalent time/effort to a marathon, I surmise that there would be a clear difference in their exercise physiology. (Maybe that’s why the study clearly state that they’ve never tested their hypotheses on runners…)

In the end, I think although there is clearly some crossover benefit, specificity training is clearly the best way to prepare for an event. Short distance runners should clearly concentrate their efforts on the track while marathon runners should stick to their consistent long runs. Clearly though, it helps for each to train in the other’s shoes every once in a while.

Thanks to F.L. for bringing forth this interesting topic for discussion!
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I spent the entire weekend packing and completely missed my long run. So instead of amassing 36 or 38 miles for the week, I got stuck at a pitiful 28 miles. Total suckiness. But at least I'm almost all packed up! Moving day is just 2 days away! Will provide some pictures of my new crib once it's a bit more presentable. Hope everyone had a great weekend!

18 comments:

Susan said...

I'm a total science nerd...love posts like this! Good luck with the move, I hope it goes smoothly!

Frayed Laces said...

Thanks for your input-- although the article is interesting, I shudder to think that people may actually take it seriously. Does your new crib have more room for when I come stay with you again?

Robert said...

Sounds complicated. I'm glad there's all you smart folks out there to figure this stuff out because it's certainly not my cup of tea.

Good luck with the move. Moving's never fun, but I'm sure it will feel very good to be living in your own (owned) place in just a couple days.

Running and living said...

I am skeptical of studies to extrapolate from mice to humans. Those discount the role of the human mind. Nice review! Hope the move goes well. Ana-Maria

B.o.B. said...

Glad you and F.L. are taking this article to task. It's very important that these studies get examined by people who are actual runners and not just by rats and scientists. I for one really appreciate you guys doing this!

D10 said...

Thanks for your opinion about this issue! I love reading about exercise science.

The Happy Runner said...

Thanks for sharing you take, Alberto. ;-)

And good luck w/the move!

runningcommentaries said...

Thanks, Alberto! I think you're right about specificity. My data are only my own, haha, but I think you're right.

J said...

28 miles is not a bad week! You are moving for goodness sake! I have yet to get 28 miles done in a week since training for the 15k! lol

X-Country2 said...

You and FL have made that article way more interesting.

I RUN LIKE A GIRL said...

Thanks for the input - and interesting article.

Good luck with the move - I bet the new place is awesome. Cant wait to see pics :)

carrie said...

I always feel smart when I read your posts! :)

joyRuN said...

So sorry to say, my eyes glazed over once they hit "PGC-1a". I promise - I'll read more carefully once I get some coffee in me :)

Your 28 miles is more than I ran in all of June.

lindsay said...

better get on that mileage lam. i'd hate to win every week... course it doesn't really matter, you'll ultimately beat me in nyc anyway :)

bill carter said...

Hi LL

Great, great post! I honestly believe that there are benefits to both types of training. I also think the real trap is in not making both HIT and ET part of a good training regimen.

Thanks and best of luck with your summer training!

Jamie said...

I love this stuff - thanks for your input! Good luck with the move!!!

Irish Cream said...

Great post! I am such a nerd when it comes to this stuff and totally love learning about the science of it all. Thanks for sharing!

Good luck with the big move--so exciting!

Run For Life said...

Oooh you're moving? Congrats! I'll have to catch up on your posts later. Good luck with packing and the move.

 
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