The simple truth – ultras don’t kill speed – TRR coach Ryan Sheehy digs into the myth and provides insight into going long AND fast!
Five weeks ago I was standing at the start line of my first 100-mile race. Today I ran an 18:50 5K — the fastest one I’ve ever run. My previous best was 20:07, set two years ago, before I’d logged a single ultra mile.
Between those two time trials, I ran five ultramarathons and covered 45 miles or more five separate times.
So either I’m an anomaly, or the conventional wisdom is wrong.
You’ve probably heard it before: the longer you go, the slower you get.
The Myth Is Real. The Diagnosis Isn’t.
The fear isn’t made up. Runners do go ultra and come out slower. But blaming the distance is like blaming your couch for weight gain. Technically adjacent to the truth, but missing the actual problem.
When runners shift to long distances, they quietly drop speed work. Every session becomes an easy run or a long run. The track disappears. The strides stop. And then six months later they wonder why their legs forgot how to move fast.
That’s not the ultra’s fault. That’s just not training for speed anymore.
Your body gets good at whatever you ask it to do consistently. Ask it to run slowly for months, and it’ll optimize for that. Ask it to occasionally move fast — even just a little — and it holds onto that too.
You Don’t Need Much. You Just Can’t Drop It Entirely.
One quality session every ten to fourteen days is enough to keep your fast legs available. Think of it like watering a plant. You don’t need to do it every hour. You just can’t forget about it for three months.
Six strides at the end of an easy run. A twenty-minute tempo on a Wednesday. A fartlek through a flat stretch of trail. None of these are big commitments. All of them matter.
Here’s a trick that works particularly well during an ultra block: do those strides and hard bursts at the end of a run, when your legs are already tired. When you push hard on tired legs, you’re training your body to access speed when it’s running on fumes — the exact scenario waiting for you at mile 70 of a hundred-miler. It keeps your higher effort zones from going completely dark during a long training block, which is easy to let happen when most of your weeks look like slow miles and more slow miles.
Speed work isn’t optional. It’s just flexible.
Hills Are Doing More Than You Think
If you’re running serious elevation, you’re already getting a version of speed work without calling it that.
Hill repeats build leg strength, clean up your stride, and improve how efficiently your body moves — the same benefits you’d get from a plyometric session, just spread out over a mountain instead of a parking lot. And frankly, a lot more scenic.
The fitness you build going up and down for months translates to the flat and the fast. Not overnight, but reliably.
The Aerobic Base Is the Secret Weapon
By the time you’re deep into a 100-mile training block, your cardiovascular system is operating at a level most short-distance runners never reach. Easy runs feel easy. Recovery between hard sessions is faster. Threshold heart rate drops.
That base doesn’t compete with speed. It supercharges it.
When you layer even a little fast running on top of a massive aerobic foundation, the speed comes back — and often surpasses what you had before. Not because the ultra made you faster, but because the base made you ready for it.
You Don’t Have to Choose
Speed and distance are not enemies. They’re just two things that need attention. Keep a thread of fast in your training. Toss in some strides when your legs are tired. Let the hills do their thing.
Both lanes are open. You just have to use them.
Ryan is a coach with Team RunRun. To learn more about him or to work with him, check out his coach profile.