The morning after a marathon, the stairs are hard. Two mornings after, they are often worse. That second-day peak is normal: delayed onset muscle soreness usually builds over the first day and peaks somewhere between 24 and 72 hours after the effort, then fades over the following days (Cheung, Hume and Maxwell, 2003).
Soreness is the part you feel. The recovery that matters for your next race goes on underneath it and takes longer.
Why does a long race leave you so sore?
Long races load your muscles thousands of times, and downhill running is the worst of it. When a muscle lengthens under load, as your quads do on every descent, it takes small amounts of structural damage. The soreness that follows is the repair process, not the damage itself. That is why a flat road marathon and a trail race with 3,000 m of descent leave very different legs, even at similar times.
How long before you can train hard again?
Longer than the soreness suggests. Feeling fine on day four doesn’t mean the muscle has finished repairing. A sensible pattern after a marathon or a long trail race:
- Days 1 to 3: walk, easy spinning or swimming. No running if it hurts to run.
- First week: short easy runs only once the soreness has gone.
- Weeks 2 to 3: build easy volume back up before any speed work.
After a 100 km ultra, stretch those windows out. If your legs feel flat on an easy run, the answer is another easy day, not a harder one.
What actually helps recovery?
The dull answers have the best evidence.
Eat carbohydrate and protein soon after
Sports nutrition guidance suggests about 1.0 to 1.2 g of carbohydrate per kg of body weight per hour for the first four hours when you need to refill glycogen quickly (Thomas, Erdman and Burke, 2016). For a 65 kg runner that is 65 to 78 g an hour, roughly a plate of nasi lemak with an extra teh tarik. Add about 20 to 40 g of protein across the post-race meal (Jäger et al., 2017). We look at protein during long events in Why Protein Matters During Endurance Events.
Sleep
Night-start races in Malaysia mean many runners finish having barely slept. Sleep is when most repair happens, so treat the next two nights as part of the race. Skip the celebratory late night if you can.
Rehydrate without overdoing it
Weigh yourself before and after the race. Drink back roughly that difference over the next few hours with your meals, not all at once.
Move gently
Easy walking and light cycling make most people feel less stiff. They don’t speed repair much, but they cost nothing.
What to be sceptical of
Anything promising to make you “recover in half the time”. Soreness can be dulled, but tissue repair runs on its own clock. Painkillers mask soreness without speeding repair, and NSAIDs straight after a hot race are a bad idea for your kidneys if you finish dehydrated.
The fastest recovery usually starts before the race. A runner who paced the first half sensibly finishes with less damage to repair. If you’re planning a long trail race, plan your race-day nutrition as carefully as your training.
References
- Cheung K, Hume P, Maxwell L (2003). Delayed onset muscle soreness: treatment strategies and performance factors. Sports Medicine, 33(2), 145-164.
- Thomas DT, Erdman KA, Burke LM (2016). American College of Sports Medicine joint position statement: nutrition and athletic performance. Medicine & Science in Sports & Exercise, 48(3), 543-568.
- Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14, 20.
