When “Slow” Feels Harder Than “Fast”: A Lesson From Marathon Training

On a recent run of Founder Running Club München, one of the runners mentioned that running slower than 6:30 pace actually felt harder for her than running much faster, around 5:15–5:30. At first, that sounded surprising — shouldn’t slower always be easier?

But then, in my own training run today, I noticed something similar. At around 5:30 pace, my stride suddenly felt smoother, springier, more efficient. The movement seemed to click into place. Whenever I try to dial back to slower than that, it feels clunky and awkward, as if I’m shuffling instead of running.

Short answer: running slower feels harder because you drop below the pace at which your body moves most efficiently. Your cadence falls, every step turns into a little braking motion, and your tendons stop returning energy like springs. Heart and lungs work less, but your legs have to manage an awkward movement pattern. So it feels heavier, even though it is physically easier.

The “Efficient Gear” We All Have

Every runner has a pace where the biomechanics just work. Cadence feels natural, stride length balances out, tendons and muscles recycle energy instead of fighting against the ground. That’s the efficient gear — the pace where running feels like it flows.

The catch: our aerobic engine often can’t support that gear for a full marathon. It may feel smooth for 5 or 10 kilometers, but try to hold it for 42 and the body eventually runs out of fuel. That’s when many runners hit the wall.

Why Slow Running Feels So Awkward

Here’s the paradox: to one day run a marathon in your smooth gear, you first have to spend months training in a less efficient one.

Running slower than feels natural — the dreaded “clunky shuffle” — is exactly where the aerobic adaptations happen:

• More mitochondria in your muscle cells
• Improved fat metabolism (so you don’t burn through glycogen too fast)
• Lower heart rate at all paces

It may feel wrong, but it builds the base you need.

The Long Game

For elite runners, their easy pace is still inside their efficient gear. Kipchoge jogging at 3:45/km looks smooth because his body is trained to handle 2:50/km for the marathon.

For the rest of us, those gears don’t line up yet — but they can. With consistent base training and higher mileage, the aerobic engine eventually catches up. That’s when your smooth stride at 5:30 isn’t just a 10k rhythm anymore — it becomes a marathon rhythm.

And when that happens, performance can jump by 15–20 minutes or more, not because your form changed, but because your engine finally matches your mechanics.

Does Running Slower Make You Faster?

Yes, but not on its own. Slow, easy running builds the aerobic base that the rest of your training stands on:

• It trains what matters over long distances (more mitochondria and capillaries, better fat burning) without piling up fatigue.
• It lets you run more kilometres per week with less risk of injury, and weekly volume is one of the strongest drivers of marathon performance.
• It keeps you fresh enough to run your few hard sessions properly hard.

That is why most endurance coaches recommend running roughly 80 % of your training easy and 20 % harder, often called 80/20 or polarised training. Slow running alone won’t make you fast. Slow running plus a little speed work will.

How to Make Slow Running Feel Less Awkward

• Shorten your stride instead of slowing your step rate. A quick, light cadence keeps the movement smooth.
• Run by heart rate or by breath: if you can hold a full conversation, you are in the right zone.
• Give it a few weeks. The clunky feeling fades as your easy pace slowly gets faster.

I wrote more about this in Why I’m Learning to Run Slower.

My Takeaway

Today’s run made something clear to me:

• Slower can feel harder.
• Faster can feel smoother.
• The key is not to chase smoothness too early, but to train the engine until smoothness and endurance overlap.

For my Lisbon marathon, that means holding back closer to 5:55–6:00/km, even if 5:30 feels easier mechanically. The long-term goal is to build enough base that one day, 5:30 is my marathon pace.

Closing Thought

If you’ve ever felt awkward running “too slow,” you’re not broken. You’re probably just discovering your efficient gear. The art of marathon training is learning to live below it long enough that, eventually, it becomes your superpower.