Training Fast Twitch type runners vs. Slow twitch

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Ok, it’s a good subject that has been discussed here quite a bit.

We all have percentages of each fiber type.

Without talking too specifically about training it is important to understand the physiology first.

The way it (it is believed) to work is your body chooses to use slow fibers first. If the force demand requires more, than the faster fibers kick in to take over.

While training for distance the most important piece of the puzzle is aerobic development.

If you run slow all the time your body will not train the faster fibers aerobically unless you are running distances that fast fibers are used simply because the other fibers are too fatigued to continue.

So if you are a fast twitch reliant athlete and a distance runner you want to apply enough pressure so that your body “chooses” to work the fast twitch fibers. The key is that these fibers need to be used aerobically. This is why Daniel’s cruise intervals and Tinman’s CV pace works. The idea of only working on your speed above threshold and slow running in between is nonsense. Don’t get me wrong in that speed development is important particularly for mid distance but you should not make it the focus.

This kind of training also helps slow twitch reliant athletes also as they have a percentage of fast twitch fibers for use also. Most have a healthy mix of both types.

Basically, for cast twitch reliant runners shorter long runs, split up tempo / threshold intervals like 2x2 miles with a break in between tend to work well. Slow twitch, longer runs with pick ups in the middle help. Even with slow twitch athletes it seems like breaking up tempos and threshold runs into intervals seems to work well.

Generally I will have my fast twitch runners running less volume but it is also because they are more focused on mid distance events.

I don’t really like using the terms “fast twitch“ and “slow twitch.” I feel like people would likely classify Jakob as slow twitch but he ran run 1:46 and 3:28. That doesn’t sound very slow twitch to me. Jake Wightman is the world champ. People probably call him more fast twitch as a 1:43 guy. Wightman and Jakob train very differently. Others in this thread say that fast twitchers have to run their mileage slower. Jake Wightman usually runs 5:45 to 6 min pace on his easy days. He’s fast twitch though. That goes against what was previously posted. Laura Muir is another person people should consider fat twitch. She also runs her easy days quite quickly. I’ve heard stories of Jakob, the slow twitcher who is meant to run his easy days quicker, walk up hills because his HR gets too high. He runs his easy days easier. So is it the opposite?

You're trying to make broad conclusions about professional athletes' muscle fiber composition based on their performances and what you think you understand about their training. Most people on these boards, myself included, don't have a fraction of the talent that Wightman or Jakob have, so it's not very productive to try to emulate them in training in my opinion.

I agree with the poster above who talked about putting "pressure" on the fast twitch fibers in training so they can learn to behave like slow twitch fibers. I have always been a good miler (4:09 PB) but I get relatively worse at running the longer the distance. I have never responded well to continuous tempo runs or even to threshold intervals, but Tinman style CV reps combined with some 200s or short hill repeats work like magic for me. Faster Vo2 max effort or mile pace work helps tremendously as well but I have to be careful not to do it too many weeks in a row. I have also found it to be very effective to run extremely slow on my easy days and long runs (3 - 4 minutes/mile slower than 5k pace which for me is 7:45 - 8:45/mile) but making sure I throw in some hard strides after my easy runs 2 - 3x/week. My legs just feel incredible going into every workout now and some of my long standing injuries have finally disappeared.

I like number 7, and I would add that you can start late and still get some hidden sprint speed! In high school and college I definitely subscribed to the idea that sprint speed was inherent and I was just plain slow. I had NO pop. Like, 14 second 100m no-pop. What I didn't realize was that we never practiced pop for cross country, and I wasn't going to get it by running 400s and 800s.

Out of college, I started doing some 50-60ish meter hill sprints outside my house in the same season when I was doing deadlifts, squats for the first time. In maybe the fourth session or so, I felt myself accelerating seemingly automatically uphill, no burning, just power, and I thought, WHOA... so that's what fast is supposed to feel like. I guess it's a sensation that kids who play sprinting sports feel all the time, but I'd literally never felt it before.

It struck me that I didn't have to try hard at all to gain speed over a few weeks; I was just doing a simple activity I'd never done before.

At 1:46 he probably goes under 50 for an open 400. I would say he has a healthy amount of fast twitch fibers. As I said we are all a mix of all the fibers. Some are more reliant on certain fibers than others.

People like to focus on easy / recovery days but they don’t typically make up the bulk of training.

Can you give some good examples of Tinman CV reps, please?