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Pure Slow Twitch Question

Posted: Wed Feb 06, 2019 5:19 pm
by ST530
A theoretical question for Tinman (or any others that care to chime in):

How would one approach training an individual who is purely slow twitch/type I fibers? I know a lot what's popularized about Tom's training (CV work and whatnot) is centered around the idea of enhancing the conversion and aerobic capacity of Type II fibers, but how would one go about developing an individual who is purely Type I, say for marathon (or even 5k/10k) racing?

I've seen Tom write about how these types shouldn't taper much before races, and that they respond well to a lot of easy running with strides for coordination. What would the biweekly workouts look like that would best stimulate Type I development, and why would they work? I get why training at ~90% VO2max velocity is beneficial to drive aerobic adaptations in Type II fibers, but what effect would that have on Type I fibers? Would sessions be better severed with longer reps at 80 or 85%?

How would Tinman handle someone like Jeff Galloway, who was something like 98 or 99% slow twitch, or Salazar who was 92 or 93%?

Re: Pure Slow Twitch Question

Posted: Thu Feb 07, 2019 9:25 am
I started to write lots of my own ideas (read well read guesses with no personal experience, I'm pretty fast twitch) on the subject. Then I decided Tom's post is enough to support the idea that a normal Tinman schedule is fine for a slow twitch runner until they are pretty good, say trying to move up on a division 1 team or qualify for the marathon trials.

From back in 2009:
Depletion of glycogen, which is the stored form of carbohydrate, is the key to stimulating growth of mitochondria in a type of muscle fiber. To maximally stimulate mitochondria growth in slow twitch fibers, most runners must reach an intensity between 80-90% of Vo2 max; above which further stimulation is limited. The reason stimulation above 80 to 90% is limited relates mostly to fatigue generated by phosphate leakage to the extra-cellular space around muscle fibers and/or acidosis. Both causes limit total duration of stimulation. Since slow twitch fiber are the biggest portion of most runners total fiber population, and since a portion of the energy used by slow twitch fibers is fat (fatty acid), it takes a lot of time (read, many km or miles) to deplete slow twitch fibers, normally, compared to fast twitch fibers, which deplete energy stores quickly.

Key:To maximize depletion in slow twitch fibers - and to a large degree fast intermediate fibers (called Type Ia), the maximum permissible dose of training must be at or near 80 to 90% of VO2 max. The paces for these are shown in my training charts, located on the homepage of The Run Zone, in the "Tinman Training Tools" file-folder. Those paces are called Tinman Tempo and CV pace.

A Tinman Tempo run of 45 minutes and a CV interval workout lasting 22.5 minutes depleted slow twitch fibers about the same. Either can be used, or a combination of the two. Add in a 10 to 15-minute warm up and the same for a cool down and you have done a great job of depleting your slow twitch fibers, thereby stimulating growth of mitochondria, capillaries, and substrate use. A simple 65-70 minute workout, including 45 minutes of Tinman Tempo running, will provide a similar effect as running for 2 hours at an EZ to Moderate pace. The same goes for a 65-70 minute workout including 22.5 minutes of CV intervals.

You don't have to run 13 miles in training to run a half-marathon. I once coached a 1:17 half-marathon runner who ran 30 miles per week and the longest run he ever did was 10 miles. He did a lot of 8-9 milers with CV or Tinman Tempo running in them, though, and striders for form, fluidity, and muscular coordination. He ran 3 times per week, did the eliptical 2 times per week, and swam once a week (the supplemental training was about 30 minutes per session, and mostly at an easy speed).



Re: Pure Slow Twitch Question

Posted: Thu Feb 07, 2019 9:38 am
As to the last part of your question:

"The thing is Salazar forgets that he ran his best marathons by using 6:30 per mile training between his "hard" workouts prescribed by Bill Dellinger. I used to have a copy of his training schedule, which showed how he trained before his first marathon. He ran his first marathon in 2:09:41 and won it - New York City Marathon. He minimally got better after that. His 2:08:13 best was on a short course. His 2:08:53 at Boston was probably just as fast. I think Salazar bombed after that because he ran too fast on easy days and upped his mileage. He commented later, after not racing well at the LA Olympic Games that he over-trained."

Re: Pure Slow Twitch Question

Posted: Thu Feb 07, 2019 12:31 pm
by ST530
Excellent - that post was very helpful! Would someone who is primarily slow-twitch do better with more or less rest between reps at Tempo or CV pace than a comparable runner who is more balanced?

Personally speaking, I’m someone who is near that level in the marathon; I’ve always thrived on higher volumes of running (200-220 km/wk) but suspect I have nearly all type i fibers. I generally do two workouts a week, with one of them being incorporated into my long run and one in the middle of the week as a farther of sorts.

Would the advice for the non-workout days (the other 5 days each week) be to run slow and easy, or would a slow twitch runner treat steady or recovery days differently than the comparable runner?

Re: Pure Slow Twitch Question

Posted: Thu Feb 07, 2019 2:16 pm
I think Tom's most direct answer to your question about shorter and longer rest between reps on here is the suggestion that faster runners often respond better to shorter CV intervals while holding rest constant. But that mostly comes from questions from runners at somewhat lower performance levels and to race distances where fiber composition differences aren't likely to make avoiding the marathon "wall" difficult.