Mileage First, Intensity Second: What Recreational Runners Can Learn from the Data
When it comes to running, most advice is centered on workouts: Should you do more intervals? Should you add tempo runs? Should you train faster than race pace? While these questions matter, new research reminds us that there’s a more fundamental lever to pull first — volume.
A large study of over 2,300 recreational runners (Vickers & Vertosick, 2016) found that weekly mileage is the single most powerful predictor of race performance across all distances. In fact, going from 30 to 50 miles per week made men ~25 minutes faster and women ~31 minutes faster in the marathon. That’s not a marginal gain — that’s transformational.
50 Miles a Week Is a Ton of Miles. But the Principle Applies Everywhere
Now, let’s be clear: 50 miles per week is a lot. That level of training takes years of gradual progression, careful planning, and serious dedication. Most recreational runners — and especially those newer to training — won’t get there, and they don’t need to.
The takeaway isn’t that you must run 50 miles a week. The real lesson is that consistent volume at your current level is the biggest lever for improvement. If you’re running 5 miles a week, building to 10 can create meaningful change. If you’re in the gym doing two sets of exercises, adding a third set — or adding a second day of training — can be the difference-maker.
The principle scales: whether it’s 50 miles or 5 miles, foundation comes first.
The Foundation: Volume as the Primary Driver
Think of running performance like building a house. The foundation is your weekly mileage — the sheer consistency of getting out the door and logging steady runs. Without it, the walls (intensity work) won’t stand for long.
The study found:
Weekly mileage strongly predicted performance at every distance — 5K, 10K, half marathon, and marathon.
Both men and women benefitted, but the effect was especially large for women at the marathon distance.
Volume was more influential than any single type of workout, shoe choice, or body type adjustment.
The practical message is clear: if you’re looking for one lever to pull to improve your times, first increase your mileage gradually and sustainably.
Once the Base is Built: The Role of Intensity
Of course, mileage isn’t the full picture. Intensity matters — but its role comes after a solid base has been built. The study looked at two major intensity strategies:
Tempo runs (threshold runs): Especially valuable for shorter distances, improving 10K performance by ~7% and half marathon by ~4%. Even in the marathon, tempos shaved off ~3–4%.
Intervals: Consistently useful across all distances, improving times by ~3%. Men seemed to benefit slightly more than women, but both groups saw gains.
Intensity training works best once you’ve already filled the “volume bucket.” Just like in rehab and strength training, if you skip the foundation and jump straight to high-intensity work, your body isn’t prepared to adapt. There’s perhaps a higher risk of injury, burnout, or plateau.
Parallels to Physical Therapy and Rehab
At Zero Point One Physical Therapy, this logic mirrors exactly how we guide people out of pain and back into performance.
Step 1: Build the base (capacity). We first focus on restoring consistent, foundational movement. Whether you’re rehabbing from a back injury or training for a half marathon, the first lever is volume — getting your body moving consistently, progressively, and safely.
Step 2: Layer on intensity. Once the foundation is in place, we add speed, load, or complexity. Just like tempos and intervals in running, intensity in rehab amplifies your performance — but only if the base is ready.
There’s no hard ground rules but hierarchy seems to matter in the long run.
Smarter Race Predictions (and Smarter Pacing)
The study also took a close look at race time prediction models. The widely used Riegel formula works for races up to a half marathon, but it dramatically underestimates marathon times. For half of runners, it predicted marathon finishes at least 10 minutes too fast.
By adding mileage data and one or two prior race results, the researchers built far more accurate marathon predictors. The takeaway? Volume not only improves performance, it helps you predict it more reliably.
The Big Takeaway
The data confirms what we see in the clinic every day:
Volume is one of the most important lever arms. Start by building consistent mileage (or consistent days/sets if you’re in rehab).
Intensity amplifies results — but only once the base is strong. Add tempos and intervals (or heavier loads, more complex moves) later.
Performance mirrors rehab. In both, we focus on building capacity first, then layering in challenge.
For recreational runners, this means you don’t have to obsess over the “perfect” interval plan. First, gradually build your mileage toward a sustainable volume. Once that base is set, then sharpen with intensity.
For clients and athletes at Zero Point One PT, it’s the same principle: we rebuild the foundation before raising the ceiling.
FAQ: Mileage vs. Intensity in Running Performance
Q1: Is weekly mileage more important than speed workouts for improving running times?
Yes. Research shows that weekly mileage is the strongest predictor of performance across 5K, 10K, half marathon, and marathon distances (Vickers & Vertosick, 2016). Speed workouts like intervals and tempos help, but their benefits are smaller compared to consistent mileage.
Q2: How much difference does mileage make in marathon performance?
Increasing weekly mileage from 30 to 50 miles per week was linked to marathon times that were ~25 minutes faster for men and ~31 minutes faster for women. Even smaller increases in mileage, such as going from 10 to 20 miles per week, can create meaningful improvements for newer runners.
Q3: Should beginner runners focus on intensity training like intervals and tempos?
Not at first. Beginners should prioritize building a consistent mileage base before adding speed work. Once the body adapts to a steady volume, intervals and tempos can be layered on to improve efficiency and race performance by an additional 3–7%.
Q4: How do tempo runs and interval training affect performance?
Tempo runs are especially beneficial for shorter races, improving 10K times by ~7% and half marathons by ~4%. Interval training is consistently effective across distances, improving performance by about 3%. Both are most effective after a solid mileage base has been established.
Q5: How does this approach relate to injury prevention and physical therapy?
Just like in running, rehab works best when you build the base first. At Zero Point One Physical Therapy, we focus on consistent, progressive loading before adding intensity. This ensures your body has the capacity to handle higher demands without breaking down.
Q6: What’s the best strategy to predict marathon finish time?
Most runners use calculators based on the Riegel formula, but these often underestimate marathon times. Models that include weekly mileage and prior race times provide more accurate predictions, helping runners pace smarter and avoid hitting the wall.
Works Cited
Vickers AJ, Vertosick EA. An empirical study of race times in recreational endurance runners. BMC Sports Sci Med Rehabil. 2016;8:26. doi:10.1186/s13102-016-0052-y
Seiler S, Tønnessen E. Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training. Sportscience. 2009;13:32–53.
Karp JR. Training characteristics of qualifiers for the U.S. Olympic Marathon Trials. Int J Sports Physiol Perform. 2007;2(1):72–92.