Let's be honest about something. The older we get, the more running can feel like a negotiation with your own body. A twinge here, a grumble from the Achilles there, the foot that decides to play up the week before a big race. I write this as someone who has spent more than one pre-marathon week anxiously prodding a dodgy foot, wondering whether to get on the plane at all. Which, you might reasonably point out, makes me an odd choice to be writing about staying injury-free. Fair enough. But it's precisely because I've spent more time than I'd care to admit nursing niggles back to health that I've gone away and read everything I can find on avoiding them in the first place. Take this as notes from someone still learning the lesson, not a lecture from someone who's cracked it.
But most masters runners get this bit wrong. The vast majority of running injuries aren't caused by your age. They're caused by what you did to your training a few weeks earlier, which means most of them are avoidable.
It's the spike, not the mileage
If you take one thing from this, take this. The single biggest predictor of a running injury isn't how many miles you run in a week. It's a sudden jump: a run much longer or harder than anything your body has seen recently (Garmin-RUNSAFE, BJSM 2025). Miss a fortnight, panic, and cram in a huge long run to "catch up", and you're more or less writing your own sick note. Build gradually, cap how quickly your long run grows, and you've removed the cause of most injuries before it happens.
Your fitness comes back faster than your legs do
There's a masters-specific trap here, and it's a sneaky one. Your aerobic engine, the heart and lungs side of things, responds to training quickly. Your tendons, ligaments and connective tissue, the bits that take the pounding, adapt far more slowly, and a little more slowly again with each passing decade. So you feel fit. You feel ready. You push the volume up because your lungs can clearly handle it. Then a couple of weeks later the calf or the Achilles lodges its objection. The fitness was real. The structural readiness just hadn't caught up. Respect that gap and you'll dodge a lot of trouble.
Recovery isn't the reward for training, it's part of it
You don't get fitter when you run. You get fitter when you recover from running: the training is the stimulus, but the adaptations that make you stronger take hold while you rest (Bishop et al., 2008). After 40 that's more true, not less. Easy days properly easy, a proper cutback week every fourth, and sleep treated as a session in its own right (lose it and both your recovery and your performance measurably suffer, Fullagar et al., 2015). Full disclosure: I'm writing this very section on roughly four hours' sleep, courtesy of a newborn who treats 3am as prime social hour, so do as I say here, not as I'm currently managing. Skimp on the recovery and all you're doing is stacking fatigue on fatigue until something finally gives.
Get strong (this is the big one)
If there's a single most effective thing you can do to stay injury-free, it's this, and it isn't running. It's strength training. (I know. Nobody took up running to do squats. Stay with me.) A meta-analysis of the research found it cut overuse injuries by roughly half, comfortably the most effective prevention going (Lauersen et al., 2014). Stretching, for the record, did nothing for injury rates. You don't need a bodybuilder's routine either. Two short sessions a week of squats, lunges, calf raises, a bit of single-leg work and some core will do more to keep you on the road than any amount of foam rolling.
And if you need a final nudge to actually do it, here's the part that sold me. The dose that keeps you injury-free turns out to be almost exactly the dose that helps you live longer. A 2026 study that followed nearly 150,000 people for three decades found a strength-training sweet spot of ninety to a hundred and twenty minutes a week, roughly your two sessions, linked to a 13% lower risk of dying early, 19% lower from heart disease, and a striking 27% lower from neurological conditions like Alzheimer's (Harvard T.H. Chan / BJSM, 2026). Do it alongside your running and the benefit climbs higher still. Best part for those of us who'd rather be out on the road than under a barbell: past two hours a week it flatlines, so you can stop feeling guilty about not living in the gym. Ninety minutes, twice a week. That might be the most valuable hour and a half a masters runner spends.
Run easy, mostly
The easy-hard balance that makes you faster also keeps you in one piece. Most of your running kept easy, a small slice properly hard, and very little in the punishing middle. (I've explained why that works in the piece on threshold pace.) Grinding every run out at a moderate effort is a quick route to both a plateau and the physio's table.
Respect the niggle
Pain is information, not weakness. The masters runner who gets away with it isn't the one who toughs out every twinge. It's the one who backs off for two or three days at the first proper warning sign, sorts it, and is running again the following week, instead of ignoring it for a month and ending up in a boot. There's no medal for running through an injury. There's just a longer spell watching from the sidelines.
And no, you're not wrecking your knees
While we're here, let's bury the myth that keeps non-runners tutting at you. Recreational running does not destroy your knees. A large review found recreational runners had lower rates of hip and knee arthritis than sedentary people, and lower than elite runners too (Alentorn-Geli et al., 2017). Sensible running is one of the better things you can do for your joints as you age, not one of the worst.
None of this is complicated. Build sensibly, get strong, recover properly, and listen when your body grumbles. Do that and the injuries that quietly sideline so many runners in their forties and fifties become far less likely. The fittest training plan in the world is worthless if you're injured on the sofa, so stay healthy first and the rest follows. Look after the body that's getting you there.