Chicago was yesterday. If you ran it, the stairs are probably the hardest workout on your calendar today. By Thursday they will not be, and that is where most post-marathon mistakes start.
Soreness fades fast. The repair underneath it does not. This post is about the gap between the two, what is happening in your legs during it, and how I would spend the next four weeks.
If you are racing New York on November 1, save this one for the week after.
The myth: no soreness means you are recovered
Most runners use soreness as the gauge. Legs hurt, take it easy. Legs feel normal, back to training.
It is an understandable rule. It is also wrong in a specific way. Soreness is mostly a signal from inflammation and sensitized nerve endings in the muscle. It peaks in the first couple of days and is usually gone within a week. The structural repair it was pointing to keeps going long after the signal stops.
So the runner who jumps into a tempo run on day eight because the legs feel fine is usually training on muscle that is still mid-repair. The typical result is not a dramatic injury. It is a flat, heavy month and a calf or hamstring that will not settle.
What 26.2 miles does to muscle
A marathon is tens of thousands of landings. Every one asks your quads, calves, and hamstrings to absorb force while they lengthen. That kind of loading, called eccentric, is what strains the fine structure inside muscle fibers.
In 1985, Warhol and colleagues published muscle biopsies from marathon runners in the American Journal of Pathology, under the title "Skeletal muscle injury and repair in marathon runners after competition." Under the microscope, they found damage to the fibers themselves after the race, along with the inflammation and cleanup that follows. That repair did not wrap up in a few days. It was still visible weeks later, and some runners still showed changes a month or more after the race.
That was a small group, studied with older techniques, so I would not hang a precise timeline on it. The direction is clear, though. The muscle you raced on is not the muscle you will be training on next weekend. It is still rebuilding.
You can see a version of this in a blood test, too. Creatine kinase is an enzyme that normally stays inside muscle cells. After a marathon it shows up in the blood in large amounts, because damaged cell membranes let it leak out. It is one of the standard markers researchers use to track muscle damage after hard running.
The tank refills more slowly, too
Muscle glycogen is the other thing you spent. Most runners finish a marathon with their legs close to empty.
After a normal hard session, a well-fed runner restocks glycogen in a day or two. After a marathon, it takes longer. A 1997 study in the Journal of Applied Physiology set out to explain why glycogen resynthesis is impaired after a marathon. It found the slowdown was not caused by a drop in GLUT-4, the transporter that moves glucose into muscle. That points back toward the damage itself, though the exact mechanism is still debated.
The practical takeaway is simple. Eat normally this week, with plenty of carbohydrate and protein. This is not the week to start cutting.
Rest or run? The research has moved
The old advice was total rest for a week or two. There is a better answer now.
In 2021, Ignacio Martínez-Navarro and colleagues published a randomized trial in the European Journal of Sport Science with 64 marathon finishers. After the race, runners were assigned to easy running, elliptical training, or rest for the following week. The exercise started at 48 hours.
Muscle damage markers, creatine kinase and lactate dehydrogenase, recovered the same way in every group. Easy running did not slow the repair. And at 96 hours, the running group jumped higher on a squat jump test than the resting group, a sign their neuromuscular function was coming back faster.
The key word is easy. Those runs were light by design. The study tells you a gentle jog from day three is fine and may even help. It does not tell you a workout on day five is fine.
Why you might get sick this week, and why that is less certain than you heard
You may have heard that a marathon opens an "open window" that leaves you prone to colds. That idea traces back largely to David Nieman's survey of runners from the 1987 Los Angeles Marathon, published in 1990. Racers were more likely to report illness in the week after the race than runners who had registered but did not race, and runners training more than 60 miles a week reported more illness.
That finding has been challenged. In a 2018 review in Frontiers in Immunology, Campbell and Turner argued that the idea of exercise suppressing immunity is overstated. Other researchers have asked whether some post-race "colds" are infections at all, or inflammation from the race itself.
The honest answer is the science is unsettled. The practical advice does not change either way. Sleep, eat, wash your hands after the airport, and do not stack hard training on top of a tired system.
How I would spend the next four weeks
This is not a formula. It is how I would structure it for most runners coming off a full marathon effort.
- Days 1 and 2. Walk. Move around. No running needed.
- Days 3 to 7. If it feels good, two or three short, truly easy runs of 20 to 30 minutes. An elliptical or an easy spin works too. Skipping running entirely this week is also fine.
- Week 2. Easy running most days, shorter than normal. Late in the week, add a few relaxed strides if your legs feel springy.
- Week 3. Volume heads back toward normal. A light fartlek is fine. Nothing timed or tested.
- Week 4. First real workout, kept moderate. If it feels harder than it should at the paces you expect, that is your answer. Give it another week.
You have probably heard the rule of one easy day per mile raced, which comes out to about 26 days. As far as I know, there is no study behind that number. I like it anyway. It lands in roughly the same place as the biopsy work, and it keeps people from racing again too soon.
My wife Aubrie has run 2:59 for the marathon and finished more than ten of them. The recovery weeks are never the part anyone posts about. They are the part that sets up the next one.
Signs it is more than soreness
Normal post-marathon soreness is broad, shows up on both legs, and improves day by day. A few things are not normal:
- Pain in one specific spot on a bone, especially the shin, foot, or hip, that gets worse as you run.
- A limp that is still there after the first few days.
- Swelling in one area, or pain that is getting worse instead of better.
- Very dark urine, or very little of it, in the day or two after the race.
Any of those is a reason to stop running and see a doctor, not to push through.
Where NXT RUN comes in
The hard part of recovery is not knowing the rules. It is judging your own legs honestly at 6 am when you want to run.
That is a good job for PACE Coach. Tell your coach how your legs feel each morning this week, and it answers with your race behind you and your next goal in view: walk, easy jog, or take the day. When you are ready to point at the next race, your coach is already caught up on where you are.
This article is general education, not medical advice. The research described here comes mostly from healthy, trained adults. If you have pain that is localized, worsening, or not improving, or any symptoms that worry you after a race, talk with a doctor before you keep running.