How to Stay Injury-Free During High Mileage Training Weeks

High mileage doesn’t cause injuries, poor load management does. Many ultra-runners handle big weeks safely, but the ones who thrive have a few habits in common.

High-mileage training can be one of the most effective ways to build the durability needed for ultras, but only if your body can absorb it.

The runners who handle big weeks well aren’t always the strongest or the fastest. They’re the ones who manage the load sensibly, listen to early warning signs, and look after the basics better than anyone else. High mileage isn’t dangerous in itself; it’s the context around it that determines whether it makes you stronger or pushes you over the edge.

The goal isn’t to survive one massive block but to string together week after week of consistent training without breakdown. That means treating recovery, nutrition, pacing, and strength work as part of the plan, not extras you squeeze in when you remember.

Handle these pieces well, and high mileage becomes a powerful tool rather than a gamble.

1. Keep the easy miles truly easy

High mileage only works when the majority of it is done at a genuinely comfortable effort. If your easy days creep up into “steady” or “moderate,” you’re no longer recovering between harder sessions, you’re just adding more stress to the system.

That’s when tissues fatigue faster than they repair. Running slowly builds aerobic capacity, strengthens connective tissues, and keeps your nervous system calm enough to absorb the next day’s load.

Peter van der Zon, Centurion coach and sports therapist, knows that “if you can’t call your mum during an easy workout then you’re probably going too hard.”

Think of easy running as your weekly scaffolding: it holds the structure together. If you take it away, the whole thing wobbles. Don’t fear being slow. Fear being tired all the time.

2. Strength and mobility aren’t extras, they’re part of the training

If you’re aiming for a big week, 80, 90, 100 miles or more, strength and mobility must sit at the heart of the plan. Not an afterthought.

A short, consistent routine protects you against overload by giving your muscles, tendons, and stabilisers the resilience they need to handle the mileage. You don’t need heavy barbell work (though it can help), but you do need the basics: calf strength for downhills, glute strength for stability, hip mobility to keep your stride smooth, and some core control to reduce compensations when fatigue kicks in.

“Can you shoot a cannon from a canoe?” Peter asks? “You need a strong core to be effective when you are running. It provides stability for the work that you put in every day”.

Ten to twenty minutes, three or four times a week, can make the difference between a strong block and a breakdown. The athletes who stay injury-free aren’t always the ones doing the most miles, they’re the ones who do the little things consistently.

Coach Pierre Meslet’s foam roller is in the living room, visible to all. “It’s very visible next to the sofa, not hidden in a cupboard. If you see it daily you’ll be reminded to use it when the time comes to chill in the afternoons/evenings”.

3. Small niggles need early attention

Most injuries don’t arrive suddenly, they whisper first. A tight calf, a pinchy hip, a sore foot on waking. Runners get into trouble when they ignore these early signs and “hope tomorrow feels better.”

During high mileage weeks, those whispers can become shouts quickly. Respond early: adjust the next session, shorten a run, swap intensity for easy miles, or jump on the bike for a day. These are small interventions, but they stop problems escalating.

“As ultra-runners we are no stranger to the ‘pain cave’ in a race” says Peter, who holidays in the pain cave on a regular basis. “But you need to be able to tell the difference between a niggle, an injury and just tired legs in racing and training”.

There’s also a psychological benefit: taking action gives you a sense of control rather than anxiety. If something feels off, address it when it’s still tiny. The runners who know how to adapt on the fly are the ones who stay consistent long enough to get genuinely fit.

Peter adds you should “never be too shy to ask your coach or a physio about something that isn’t right”.

4. Fuel more than you think

High mileage increases your energy demands massively. If you don’t match that with enough intake, your body starts cutting corners: hormones shift, recovery slows, tissues weaken, and injury risk climbs.

Many niggles blamed on “too much mileage” are actually caused by too little energy. Eating well around runs, especially after long or hard efforts, boosts glycogen restoration, supports tissue repair, and keeps your immune system functioning.

This is all especially important during multi-day high load. A simple rule: if mileage goes up, calories must go up. And don’t fear carbs, they’re your friend when the weekly total climbs beyond normal.

Peter’s top tip? “Chocolate Milk. It has fluid, carbs and protein. Plus it tastes nice and isn’t too expensive”.

5. Sleep is your recovery system

Sleep is where the real adaptation happens. Deep sleep triggers growth hormone release, repairs muscle fibres, reduces inflammation, and restores the nervous system after long back-to-back days. When mileage climbs, your sleep-needs climb too.

Physio and osteo Pierre says that “when I move towards higher mileage weeks or during (multi-day races such as Marathon des Sables) I try to plan my week and pick a couple of days when I’ll be able to add a short power nap. I’ve found it a great way to recover faster and perfect to handle double days well.”

The combination of high training load and poor sleep is one of the fastest ways to break down. You don’t need to overhaul your life, even 30-60 minutes more per night can dramatically improve resilience.

More wisdom from coach Peter is that you “shouldn’t be afraid to change your training if you have a bad night’s sleep. Your coach will be happy if you update them and make a wise choice. If it is a poor level every night, then you know you have to adapt”.

Prioritise a consistent bedtime, keep screens out of the last 30 minutes of the day, and protect your sleep like it’s part of the training plan, because it is.