Myth of the 10 percent rule for running

Many runners are overly cautious when increasing weekly distance, following the 10 percent rule as gospel!

But what if the 10 percent rule wasn’t a rule at all? And 10 percent of what anyway??

What is the 10 percent rule for running?

The 10 percent rule for running states that any runner should only increase their training by 10% per week.

It’s said that the 10 percent rule will reduce the risk of injury and allow a safe build up of weekly volume.

Is the 10 percent rule flawed?

Firstly the 10% “rule” is a concept rather than a rule. It describes building up exponentially, which is super risky!

As an example, if you’re doing a 3km long run this week (like in a C25k/parkrun program), you’d increase to 5.8km after 8 weeks.

But if you’re running a long run of 20km this week, you’d increase to 39km by week 8. That’s workable for some but risky for others.

If you’re running 40km/week with a 20km long run, it looks even more implausible. If your other runs remain the same, 10% more volume each weeks ends with a long run of 58km after 8 weeks! Ummm….

How fast should you build up?

The limiting factor for any endurance running is being able to maintain a good running technique.

After you lose good running form, your efficiency goes down (requiring more effort to run the same pace) and your injury risk goes up (due to abnormal loading on the body).

So you can build up faster if you’re fit and strong as you’ll be able to maintain good form.

If you’ve got a decent running history, you can build up faster as your technique should be well refined and quite efficient.

Even if that history isn’t current, you’ll pick up the same technique and movement skills quicker than someone who is running for the first time.

Can you take extra precautions to reduce the risk of injury?

Increasing weekly running volume is one of the riskiest periods for a runner.

Taking a day off between runs is good as a buffer. It allows the body time to recover but it will also reduce your effective weekly training days.

As a compromise, try working in 3 day blocks with a rest day every 3 days. That still provides the chance to run on tired legs but mitigates the risk of ongoing fatigue-related overload.

Also think about working in long blocks and adding an easier week every 3-5 weeks. It gives you a chance to spike your weekly loading in the week before the easier week, knowing you’ll recover soon afterwards.

The fastest way to build up weekly distance and long runs

Muscle strength is what will maintain your technique throughout a run.

Injuries occur when your technique breaks down and your muscles, bones and joints are exposed to abnormal loading.

The plan

Twice a week, go for your regular moderate to long distance run.

As soon as you finish, complete a short (20 minute) bodyweight or light weight strength session. Make it as running-specific as possible, but you can throw in some upper body as well.

If you can comfortably complete the strength work with good form, you can safely assume your running form would have lasted an extra 20 minutes longer on your run.

Next run you can safely go for a longer run, increasing by the duration of the previous week’s strength training session. So two 20 minute strength sessions buys you 2 x 20 minutes more running, or 6-8km for most runners.

It’s the safest way to build weekly distance. And after adding strength work post-run for a few weeks, you’ll also notice a boost in performance. So it’s win-win!!

Based on a reply written for Reddit’s r/running forum by the author.