The single run that predicts running injuries
Daylight savings and running season
Kia ora! Yes yes, daylight savings is here! Always an exciting time of year, because it means summer is on its way (my favourite season).
On my usual commute run home earlier this week, the sun was shining and the footpaths were full of runners. Great to see.
We've been on a bit of a "run" of running topics lately (pun intended). For our non-runners out there, don't worry, we'll shift gears soon. The reason we're focusing on running right now is that we're seeing a flurry of running-related injuries in the clinic. With the Auckland Marathon events coming up (including the Half Marathon and the 11km Traverse), we're helping a lot of people get back on track.
Why injuries happen
These injuries tend to come in cycles, and this time of year is always busy. Classic reasons include:
Ramping up mileage too quickly
Increasing training frequency too quickly
Increasing pace too quickly
Suddenly starting hill repeats or interval training
New shoes (and not adjusting to them)
Skipping rest days
Only starting training now, so close to the event
The theme? Too much, too soon.
The "10% rule" vs the long run effect
For years, runners have been told to follow the "10% rule": don't increase weekly mileage by more than 10%. But recent research suggests that one of the clearer warning signs isn't your total weekly distance. It's how your longest single run compares with what you've done recently.
What the research found
A large study by Frandsen and colleagues (2025) followed over 5,200 runners for 18 months, looking at how spikes in training were linked to overuse injuries.
The researchers compared:
Weekly mileage changes
Each single run compared with the runner's longest run in the previous 30 days
Compared with runs that stayed within 10% of the recent longest run, the results were:
Small spikes (10–30% longer than the recent longest run): about 64% higher injury rate
Moderate spikes (30–100% longer): about 52% higher
Large spikes (more than double): about 128% higher
Weekly mileage changes showed no clear link.
Bottom line: in this study, big single-run jumps were linked with injury, while weekly totals weren't. It's an observational study, so it shows an association rather than proof of cause, but it's a useful way to think about your training.
What this means for you
Think session by session, not just week by week.
Use the 30-day longest run as a guide: try to keep any single run within about 10% of your longest run in the past month (funny how the old 10% rule still sneaks back in).
Watch the "hero run": that big Sunday long run is often where injuries creep in.
Return from injury carefully: build your longest run back gradually, not just your total weekly distance.
Consistency beats heroics. Avoid over-ambitious single sessions and you may lower your risk of injury, giving yourself the best chance to run stronger for longer.
Early intervention helps
Got a niggle in your calf, knee or Achilles? Don't wait until it stops you running. Our guide Niggle or Injury? covers how to tell a normal training niggle from one worth getting checked.
Our physios see a lot of running injuries and can help you train safely through the final weeks.
Want more running tips?
Check out our other blogs to help you train smarter:
Niggle or Injury? How to Decide What to Do Before Auckland Marathon
Auckland Marathon 2026: How to Taper, What to Do in Race Week, and How to Recover
Smart, gradual progression is one of your best defences against injury. Focus on your longest runs, train consistently, get support when needed, and you'll be ready to go (all going well… kia kaha!).
