How to Train for a Half Marathon Without Ending Up Injured
Running · Half Marathon
By Alex Stott · Stott Performance · Running
Right, let's have an honest conversation about half marathon training, because it's the distance where I see the most injuries land — and it's rarely the distance itself that's the problem.
A half marathon is a serious step up from a 10km; not just further, but a different kind of demand on the body. You're now asking your tissues to hold up under repeated loading for well over an hour, often on tired legs from the accumulated weeks of training before it. Done well, that's entirely manageable for most people. Done by simply “running more each week,” it's where a lot of niggles turn into genuine injuries.
Where it goes wrong — and why, physiologically
The single biggest cause of half marathon training injuries isn't bad running form; it's rate of load increase relative to how quickly your tissues can actually adapt. This isn't a vague idea — it comes down to genuine differences in adaptation timelines between tissue types.
Muscle protein synthesis responds to training within roughly 24–48 hours; muscle, relatively speaking, adapts fast. Tendons and connective tissue are a different story. Collagen synthesis in tendon tissue is driven by mechanotransduction — mechanical loading signalling specialised cells called tenocytes to remodel and strengthen the collagen matrix — but that process, and the cross-linking that gives mature collagen its strength, unfolds over weeks, not days. Bone follows a similar pattern: bone continuously remodels according to the load placed on it (a principle often referred to as Wolff's Law), but osteoblast-driven bone formation lags behind the osteoclast-driven resorption that happens when load increases too quickly, which is exactly the mechanism behind the continuum from a simple stress reaction through to an actual stress fracture.
So what does this mean practically? You can feel fitter — your cardiovascular system and muscles adapting quickly — while your tendons and bones are still weeks behind, quietly failing to keep up with the load you're already handling. That gap, not bad luck, is where injuries like IT band syndrome, patellofemoral pain (runner's knee) and shin splints tend to show up, usually a few weeks after the mileage jump that actually caused them.
So what does it look like to train around this properly?
Three things matter more than almost anything else for half marathon training:
• Progressive overload with genuine restraint — a commonly used guide is keeping weekly mileage increases to around 10%, but the more important principle is building in regular lower-load weeks every three to four weeks, giving collagen remodelling and bone formation time to actually catch up rather than just accumulate fatigue on top of fatigue
• Strength training that specifically targets the areas half marathon training loads hardest — glutes, hips and calves — since these are the muscles that fatigue and lose stability over the second half of a long run, which is exactly when most injuries start; strength work also directly stimulates the mechanotransduction signalling that drives tendon adaptation, effectively speeding up the slowest part of the whole process
• Genuine recovery built into the plan, not treated as optional. Sleep, easy days that are actually easy, and enough total recovery between hard sessions are what allow collagen synthesis and bone remodelling to actually happen; without it, you're accumulating training stress faster than your tissues can turn it into resilience
The metabolic side: why long runs matter beyond just “time on feet”
There's also a fuelling dimension unique to this distance. A half marathon is long enough that fat oxidation and glycogen management genuinely start to matter, in a way they rarely do over a 5km or 10km. Well-structured long runs train your muscles to rely more on fat as a fuel source at a given pace (partly through the mitochondrial and capillary adaptations covered in earlier pieces), sparing your limited glycogen stores for later in the race. This is the physiological reality behind “hitting the wall” — it's very often glycogen depletion at a point where fat oxidation hasn't been trained enough to pick up the slack — and it's a big part of why simply repeating 10km-style training doesn't prepare you properly for 13.1 miles.
The bit people skip
If I had to pick the one thing that prevents the most half marathon injuries, it's the strength work — specifically because it's the first thing people drop when training gets busy. It feels optional next to the running. It isn't, and the tissue-adaptation science above is exactly why. The runners I see get through half marathon training injury-free are, almost without exception, the ones who kept their strength sessions in through the whole block, not just the first few weeks.
Ready to train properly for it?
Our half marathon programme is a 12-week plan built around exactly this balance: a running progression that respects how tendons, bone and metabolism actually adapt, paired with the strength work that protects you through the toughest weeks of training. It's a one-off payment of £44.99, delivered through your own CoachRX portal so your plan, sessions and progress are all in one place.
Working up through the distances? The Running Progression Bundle gives you the 5km, 10km and half marathon programmes together for £125.