Progressive Overload: Getting Fitter Without Getting Hurt

How to build

Raise load in small steps and find the weekly volume you can repeat. The usual rhythm is two or three weeks up and one lighter. It is a habit and not a law: the plan for the phase stays, and how you are recovering decides whether a day is hard, easy or off. Pain that sharpens as you run, or soreness that does not clear between runs, is a reason to back off (see the guide on pain versus soreness).

Add one new stress at a time. Do not add mileage, intensity and hills in the same week, and when you add strength work, make room by shortening an easy run, not by dropping the key runs.

Size every long run against the running you do now, not against the longest run you once did, and add to it in small steps. The guide on long runs covers how long a long run goes.

Do not make up a missed run, even a long one. After a missed week, restart with a short run to see how you feel, and treat a missed or rough week as a repeat and not a failure. See the guide on returning to running after a longer break.

What studies of runners found

In 5,205 runners followed for 18 months, 35% had an overuse injury, and a single run longer than 10% above the longest run of the previous 30 days was associated with a higher injury rate (about 1.6 times as often for a 10 to 30% jump, 1.5 times for 30 to 100% and 2.3 times for more than 100%). The week-to-week change in distance showed no relationship to injury¹. It is an observational study, so it shows the association and not that a longer run caused the injury, and its limit is a rough guide for runners like the ones it followed, at middle mileages, not for a new runner or a very high-mileage one.

The 10% weekly rule is not protective by itself. In a randomized trial of 532 novices, a 13-week program built on the 10% rule had the same injury rate as a standard 8-week program, 20.8% against 20.3%². That trial is from 2008. A 2022 systematic review of 36 articles and 23,047 runners found the evidence linking weekly distance, duration, frequency, intensity or recent changes in them to injury conflicting, and advised caution when recommending optimal progressions³.

Ratios of recent load to longer-term load do not settle it either. In 461 recreational runners, the acute:chronic ratio was weakly associated with injury, the association disappeared after excluding runners who were already injured, and the authors called the clinical relevance questionable⁴. There is no safe weekly percentage to follow, so judge each week by how you recover. The guide on training load and recovery covers the rest of the evidence.