Five golden rules to remember when attempting sub-3

Breaking three hours in the marathon isn’t about luck, talent or carbon plates. It’s about doing the things that matter — and doing them well, over time. Certain principles come up again and again in the lives of sub-3 runners. Not tips. Not trends. Just the core truths that hold up across blocks, across seasons and across people.

We’ve gone through every article on this site to pull out the five most consistent foundations. These are the golden rules. If you’re serious about breaking three hours, these are the mantras to carry with you. Say them to yourself on the tough days. Let them shape your training. Build your block around them.

1. Nothing new on race day

This rule has saved more marathons than any sports drink ever invented. Race day is not the time to experiment. That gel you’ve never tried in training? Leave it. The brand-new supershoes straight out the box? Forget it. The extra-strong espresso you think might give you a boost? Bad idea.

You train for months to remove uncertainty. The marathon is long enough without adding variables. Every part of your routine – kit, fuel, shoes, pacing – should already feel familiar before the gun goes off. There are no bonus points for bravery. Sub-3 is about control. Stick with what you know.

2. Mileage makes the marathon

You’ll hear all sorts of theories about how to train. But across every sub-3 account we’ve reviewed, one thing stands out above everything else: volume. It’s not glamorous and it’s not a shortcut. But it works. Consistent high mileage builds the aerobic base you need to sustain pace deep into the race.

That doesn’t mean every week needs to be huge. But if you want to go sub-3, you’ll almost certainly need to run more than you ever have before. Not in one heroic week, but over months of smart, patient training. The engine matters. Mileage builds it.

3. Drop weight, not strength

The impact of excess body fat on marathon performance is undeniable. Drop five kilos and you’ll feel it immediately – every climb, every surge, every step after mile 20 becomes easier. But weight loss alone isn’t the goal. You’re not chasing a number on the scale. You’re building a better machine.

What matters is composition. The focus should be on fat loss, not muscle loss. You want to be lighter, but not weaker. That means training smart, eating enough protein, and staying strong through the block. The fastest versions of ourselves aren’t just leaner – they’re more resilient too.

4. Every block needs bite

Mileage builds the base, but it won’t carry you across the line by itself. If you want to run fast, you need to train fast. That doesn’t mean hammering every run. It means knowing where the sharp edges go. Tempo runs, threshold intervals, fast-finish long runs – these are what give a training block its shape.

You don’t need a complicated plan. But you do need purpose. Cruise control won’t cut it if you’re serious about sub-3. Put some bite into every block. Train your legs to turn over when they’re tired. Practise race pace. Get comfortable being uncomfortable. Because come race day, that’s what it’s going to take.

5. Sub-3 is earned, not given

No one drifts into a sub-3. You don’t stumble across it after a few casual weeks of jogging and the odd parkrun. It takes consistency, structure and grit. Not just when things are going well, but when they’re not. It means running when you don’t feel like it. Sticking to the plan when life gets messy. Choosing effort over ease, again and again.

But here’s the good news. Sub-3 is possible for far more runners than most people think. It’s not a lottery win or a genetic gift. It’s a commitment. If you’re willing to do the work and live these rules, you’ll get there. And when you do, you’ll know you earned it.

A sub-3 marathon is within reach for more runners than many realise. But it doesn’t happen by accident. It takes structure, commitment and a clear-eyed approach to training. These five golden rules won’t guarantee you break the barrier – but they’ll tilt the odds in your favour. Stick them in your head. Return to them during your sessions. Let them shape your block. Because if you’re chasing sub-3, these aren’t just tips. They’re the path.