Pain When Running: When to Push, When to Stop

No topic in running is handled as badly as pain. One camp says: push through, pain is part of it. The other says: stop immediately or it becomes chronic. Both pieces of advice are blanket statements and both cause damage. Runners do not have a pain problem — they have a dosing problem. What is missing is an instrument that turns a vague sensation into a decision: keep running, adjust, or stop. That instrument is the pain traffic light, and it works remarkably precisely when applied correctly.

Why "pain means stop" and "pain means ignore it" both fail

Anyone who pauses at every twinge loses exactly what makes them resilient: training volume, strength and the tissue's adaptation to load. Studies show measurable drops in tendon and connective tissue capacity after several weeks of consistent unloading — rest is not a cure, it is one training stimulus fewer. The reverse holds too: anyone who ignores every pain signal converts a harmless irritation into a structural injury. An irritated tendon becomes a tendinopathy, slight cartilage friction becomes anterior knee pain, a stress reaction in bone becomes a stress fracture.

Both extremes share the same thinking error: they treat pain as a yes/no signal. In reality pain is a gradual signal that can be calibrated. The key question is never "does it hurt?" but "how much, where exactly, and how does it respond over the next 24 hours?". Those three questions are exactly what the traffic light answers.

A second point matters: pain is not a measure of tissue damage. Soreness hurts and is harmless; a stress fracture in the midfoot can start as a dull pull. That is why the traffic light needs two extra filters — location and warning signs. Both are covered in this article.

The traffic light in three stages

The basis is a simple 0 to 10 scale, as used in sports medicine. 0 means pain-free, 10 means severe enough that you have to abandon the run. The second factor is the response: if the value on the next morning is unchanged, the load was tolerable. If it rises, the load was too high. Those two numbers produce the colour.

• Green (0–2 points). No pain, or a barely noticeable tightness that fades after warming up and does not return the next day. The plan continues as written. No reason to change anything, no reason for a guilty conscience.
• Amber (3–4 points). Noticeable pain, but tolerable, and back at baseline the next day. Training is allowed, but not at the planned volume: drop the intensity peaks, cut volume by 20 to 30 percent, avoid hilly terrain. If amber stays stable for two or three days, ease back up gradually.
• Red (5 points or more). The pain changes your gait, you limp, or it drags beyond 24 hours. End the session. No "just the last two kilometres". The next day is walking instead of running, and if red does not drop to amber within three days, it needs a medical assessment.

Important: the traffic light does not judge a single second, it judges the course. A brief stab in the first minute that disappears after 500 metres is green. Pain that starts at kilometre two and is still there at kilometre eight is amber — no matter how tolerable it feels.

The 24-hour test: the actual measuring instrument

If you remember only one rule from this article, make it this one: assess pain not during the run but the next morning. The body responds to load with a delay of several hours. An irritated structure that still cooperates during training typically speaks up at night or on the first steps out of bed. That is where you see whether the dose was right.

In practice: after the run you note the highest pain value during the session. The next morning, before the first coffee, you note the value at rest and on the first walk. If the morning value is lower than or equal to the baseline before training, the session was tolerable and you may take the next step. If it is higher, you go back one stage. This feedback is reliable enough that it serves as a standard criterion in tendinopathy therapy and in rehabilitation after bone marrow oedema.

The test needs two weeks of discipline, then you have a feel for your own thresholds. Two numbers a day, in a notes app or a training log — nothing more. What you gain is the difference between "I have a bad feeling in my knee" and "amber for three days, so tomorrow's intervals are off".

What the location of the pain tells you

The second filter is localisation. Some pain sites in running are typical for load reactions that respond to dosing. Others are typical for causes you cannot train away — and then no traffic light helps, only a diagnosis.

• Front of the knee, below the kneecap. Often runner's knee from too rapid a volume increase or weak glutes. Responds well to adjusted load and strength work — see Runner's knee: causes and exercises.
• Outside of the knee. Typical of iliotibial band syndrome, especially downhill and on curvy routes. The tract needs load adjustment, not stretching.
• Inner shin, along a line. Points to shin splints or, with pinpoint tenderness, to an emerging stress reaction. The latter is a red flag — the traffic light is too coarse here.
• Achilles tendon, two to six centimetres above the heel bone. The classic: responds to volume jumps, speed work and climbs. Basics in Achilles tendinopathy.
• Sole of the foot at the heel, worst in the morning. The plantar fasciitis pattern: the first step out of bed hurts most. Details in Plantar fasciitis in runners.
• Migrating or radiating. Radiation into the leg, tingling, numbness — that is not a load reaction but a nerve issue. Get it assessed, do not train through it.

Seven red flags: where self-management ends

The traffic light is a tool for load reactions, not for injuries. There are signs where any further discussion about training dose is wrong. If one of these seven appears, you do not adjust — you pause and get assessed:

• Pain above 5 out of 10 that increases during the run instead of easing.
• Night or rest pain. If it hurts without load, the irritation threshold has been crossed.
• Visible swelling or heat in one region compared with the other side.
• Instability or giving way — the joint yields, especially walking on uneven ground.
• Locking, grinding with loss of strength or the feeling that the joint no longer tracks.
• Numbness, tingling, radiation into the leg or foot — a nerve signal, not a muscle signal.
• No improvement after three days of adjustment. If reduced volume and no intensity changed nothing after 72 hours, the information for the next step is missing.

For home use this is enough: one item from this list does not automatically mean a serious injury, but it does mean the decision is no longer made at the kitchen table. A sports physician or a physiotherapist with a sports focus can clarify in a 20-minute examination what the traffic light cannot.

Adjust the load instead of stopping: the order of levers

With amber, the worst response is a complete training stop. The second worst is "carry on as planned and hope". In between sits a ladder of five levers, worked from top to bottom — each one reduces load without destroying the aerobic base.

• 1. Remove intensity peaks. Intervals, tempo runs, hill sprints and strides go first. The peaks are almost always the trigger, not the easy kilometres. Steady pace in the base range stays.
• 2. Cut volume. Weekly kilometres down to 60 to 80 percent, the long run clearly shortened. Cumulative volume is the strongest driver of overuse injury.
• 3. Reduce frequency. Instead of five runs per week do three or four and fill the free days with cycling or aqua jogging. Cross-training keeps endurance without loading the affected structure.
• 4. Change surface and profile. Hills, trails and corners create shear forces. Flat, even paths and asphalt loops are more tolerable. For knee and tendon issues the track is often the most controlled option.
• 5. Check footwear. A very soft shoe with a high drop changes the load on the Achilles and ankle, a stiff carbon shoe changes forefoot load. Switching to a moderate training model is a legitimate test — see When to replace running shoes.

The big advantage of this ladder: two weeks of adjustment might cost you five percent fitness, but not eight weeks of forced rest. And you learn which lever works for you. Anyone back to green after two amber weeks knows immediately where to turn next time.

The most common mistake: the good week

Almost every runner knows the pattern. One amber week, adjustment, pain gone. Then comes a week where everything feels easy — and with the pain, the caution disappears. Volume jumps back to the old level, intervals return, and ten days later you are at the same point, this time with a week more lost.

The reason is structural: being pain-free is not the same as being load-tolerant. The inflammatory response settles faster than the tissue remodels. That is why the return needs a ramp, not a jump: at most 10 to 15 percent more volume per week, intensity only back once two weeks have been stably green. The same rule appears in Increasing training volume and it is the most important difference between runners who get injured once and those who get injured three times a year.

An effective antidote is written documentation. Anyone who logs volume, pain value and morning response over four weeks sees the pattern in front of them instead of relying on memory. It is the same mechanism fitness curves work on — key terms in the Peakora training glossary.

Pain that is not an injury signal

Not every pain in running needs a traffic light. Three patterns are so common and so harmless that you should know them in order not to pause unnecessarily.

• Delayed onset muscle soreness. Two to three days after unfamiliar load, diffuse, bilateral, tender to pressure. No reason to worry, no reason to stop — easy movement even speeds recovery. Details in Muscle soreness: what actually helps.
• Side stitch. Stabbing pain under the ribcage, usually right side, breathing-dependent. Eases with a calmer pace and deeper belly breathing. Not a structural problem, see Side stitch while running.
• The warm-up tightness. A pull in the calf, Achilles or thigh in the first two or three minutes that fades as blood flow rises. Green, as long as it fades every time and does not return later in the run.

The distinction sounds trivial but matters daily: anyone who treats soreness like an injury trains too little. Anyone who treats an emerging stress reaction like soreness trains too much. The difference is localisation — soreness is diffuse and mid-muscle, bone pain is pinpoint.

How Peakora handles pain

Peakora is not a diagnostic tool and does not replace a doctor. What the engine does is the arithmetic behind the traffic light. If you mark a session as hard or painful, you can reduce the volume — the adaptive planning feeds the changed load into the fitness curve and does not immediately propose volume jumps again just because two days went well. The recovery monitor shows whether the unloading actually arrived or whether extra sessions pushed total load back up. And because downtime can be planned instead of improvised, the plan stays coherent even when three weeks do not go to script. For the long-term frame see the marathon pillar page, for the return after a break Return to running after injury.

Common mistakes in handling pain

• Assessing pain in the evening. By then the acute reaction has faded and the value looks better than it is. The next morning is what counts.
• Treating only the pain site. Knee pain often originates in the pelvis, an Achilles problem in calf strength. Without looking at the chain, the complaint returns.
• Painkillers before the run. Anyone who chemically switches off the feedback loses exactly the signal the traffic light works with — and risks structural damage at unchanged training load.
• Pausing without a replacement stimulus. Three weeks of doing nothing costs more fitness than three weeks of smartly dosed alternative training.
• Only using the traffic light when something is acute. Anyone who runs it permanently — one pain value per week and a look at volume — spots overload before it hurts.

Frequently asked questions