The Biggest Limiting Factor Holding Back Your Running

Social media is full of mixed running advice: “The secret to running faster,” “This interval will boost your speed,” “Zone 2 is a myth.” The noise is endless, and it’s hard to know your next step. In this article, I’ll cut through the confusion and show you the single biggest factor holding most runners back from their next PB.

Marathon Times Vs Running Volume Study

A study analysing Strava data compared marathon finish times with training volume. The results were clear: the more you run, the faster you run. For the majority of runners, it’s not fancy workouts, special shoes, or perfect pacing that limits performance — it’s weekly mileage. Here’s the graph from the study:

Runners were grouped in 30-minute finishing brackets from 2:00–2:30 all the way to 6:00–6:30. Across every bracket, higher mileage meant faster times. Even an extra 5–10 miles per week made a huge difference for those running over three hours.

Diminishing Returns

Below the three-hour mark, gains from extra mileage start to taper off, requiring a larger amount of miles for a similar decrease in time. For the majority of runners, adding miles is still the most effective way to get faster. Now that this is understood, let’s look at how to do this safely.

How to increase mileage while limiting the chance of injury

Now you know you may need to increase your weekly mileage, it is important to do so in a safe manner, minimising the chance of injury. Here are a few tips to prevent you from burning out or getting injured.

Follow the 10% Rule — Increase weekly mileage by no more than 10% to let your body adapt. The exception is if you’re returning to a mileage you’ve previously run comfortably, in which case you can progress faster.

Focus on Aerobic Running - The majority of the increased weekly mileage should be Zone 2 (easy) running. By making the extra mileage easy miles, you limit the stress being placed on your body while increasing fitness.

Running the Correct Runs - 1 long run, 1 - 2 hard sessions, the rest are easy miles per week. Ensure the easy miles are really easy, so you can really push on the hard sessions.

Strength and Conditioning - When increasing weekly mileage, strength and conditioning help prevent injury and improve running efficiency. Strong muscles stabilise joints and support good form. Conditioning builds durability to handle the impact of more miles.

Life Restrictions

It’s easy to see elite runners logging 100+ miles a week and think you’re falling short. The truth is, most of us aren’t full-time athletes — we’re balancing work, family, and everything else life throws at us. Running matters, but it’s not the most important thing. The goal is to make it fit your life, not take it over.

You can still increase your mileage without huge time sacrifices. Small, consistent changes add up fast:

• Run-commute all or part of the way to work

• Break runs into shorter, more frequent sessions

• Use family or social time as active time (pram runs, laps during kids’ practice)

• Follow the 10-minute rule — start with a short run and see where it takes you

• Time-block runs into your week like meetings

I am running a shorter race. Does this still apply?

Now, if you are a sprinter, feel free to ignore this advice. However, even for shorter races like the 5K or 10K, mileage still matters. Olympic 800m runners average 50 to 70 miles a week for a race lasting less than two minutes. If you’re racing 5K and up, extra miles can still be your fastest route to a new PB.

For most runners, more miles equals more speed, but only if you build them safely. Train smart, stay consistent, and remember: an injured runner logs no miles.

Thanks for reading — if you found this useful, share it with a fellow runner.

Oli