Why Distance Is Better Than Time for Ultra-Marathons

Yes, time-based training is brilliant (we even wrote an article about it). But mileage can be too. Plus we love a bit of balance.

“For certain runners and certain races, distance-based training can be a better choice, " says Head of Endurance Robbie Britton. “The best coaches don’t pick one system; they pick what suits the athlete, the course, and the context and that can vary from time to time”.

Here’s why mileage still matters, and why for some ultra-runners it may even be the best option.

1. Mileage reflects specificity

Many ultra races are measured in distance: 50 km, 100 km, 100 miles. Your ability to cover long distances efficiently matters, and mileage directly reflects this.

Why it’s useful:

• Pacing familiarity comes from running known distances
• You build a clearer sense of what “20 miles” feels like at different efforts
• Road-based or runnable ultras require pace calibration, and pace is distance-dependent
• Mileage gives a close proxy for the tissue loading of sustained running

In the same way that a 20 mile run could be 2 hours for one runner on the road and 6 hours for another in the mountains, the same could be said for a 100 mile race. Robbie adds that “Two runners training for the same event could have a 200% difference in the finish time, so this might change the specific demands that race put on each individual”.

2. Speed development responds better to distance

If an athlete has a goal to improve:

• marathon time
• top-end aerobic pace
• lactate threshold
• sustained tempo durability

Mileage sometimes drives these adaptations more predictably than time. A 10-mile tempo run gives a different training stimulus than “a 75-minute run” because distance creates a behavioural anchor for sustained pacing.

Ideal for athletes running:

• road ultras
• flatter 50Ks
• multi-loop events
• any race where efficiency beats strength (link to another article on this)

3. Mileage can help with psychological readiness

Runners are emotional creatures (in the best way). Confidence isn’t just built from physiological readiness, it comes from experience and the stories you tell yourself during training. Mileage provides solid, memorable markers that stick in your mind far more clearly than “I ran for a few hours.” Distance creates a bank of tangible proof you can draw on when things get wobbly late in a race.

It’s powerful to be able to say:

• “I know I can run 30 miles comfortably.”
• “I’ve done back-to-back 20 milers and felt strong the next day.”
• “I ran 75 miles this week and held it together.”

Those aren’t just training stats, they’re psychological anchors that help calm the mind at mile 70 of a 100-miler, when everything feels fragile and you need reminders that your body can, in fact, cope with long distances.

Time-based training, while brilliant for managing load, can feel a little abstract in comparison. “I ran for three hours” doesn’t always carry the same emotional weight as “I covered 22 miles.” Runners often lean on that sense of measurable accomplishment, and mileage gives them unmistakable evidence that they’re ready.

In summary

Distance-based training needn’t be seen as inferior, it’s simply designed to target a different set of adaptations.

For runners preparing for flatter or more runnable ultras, aiming for specific performance goals, or wanting to develop long-term durability and pace awareness, mileage can be an incredibly powerful tool. It builds confidence, sharpens efficiency, and exposes weaknesses that time-based training can sometimes smooth over.

“As a coach who primarily uses time to set training there is still a place for a distance based workout,” feels Robbie. “It depends on the athlete and what they are training for. And if someone loves to train to mileage we can’t just ignore that as it will still matter to them”.

The key is understanding what your event demands. If your race is defined by rhythm, smooth pacing, and holding form for hours at a time, then distance-based work often gives you the most specific preparation. If your race is dictated by climbs, descents, technical terrain, or big swings in intensity, then a time-based or blended approach may fit better.

The smartest coaching isn’t “time vs distance” but knowing when each method serves the athlete. The right tool, for the right runner, at the right point in their training, always wins.