Shin splints is a rubbish name for a real problem. It gets used for anything that hurts between the knee and the ankle, which means people arrive having been told they have it without anyone establishing what is actually going on.
The proper name is medial tibial stress syndrome, and it describes a specific thing: an ache spread along the inner edge of the shin bone, brought on by running or jumping, caused almost always by asking the leg to do more than it was ready for.
What is happening in there
The bone is not the passive scaffold people imagine. It is living tissue that remodels continuously in response to load, and remodelling has a lag: the initial response to new stress is a period where the bone is temporarily weaker before it becomes stronger.
Increase your running sharply and you can spend several weeks in that window. Meanwhile the muscles along the inner shin, which attach to the bone through a sheet of connective tissue, are pulling on a surface that is already irritated.
This sits on a continuum. At one end is a diffuse ache spread over several centimetres, which is medial tibial stress syndrome. At the other end is a stress reaction and then a stress fracture, where the bone has failed at one point. Same mechanism, different severity, very different management.
Telling it apart from a stress fracture
This is the part that matters most, and you can do a reasonable first pass yourself.
| Shin splints | Stress fracture | |
|---|---|---|
| Where | Spread over 5 cm or more | One specific point, often thumb sized |
| Pressing on it | Sore over a broad area | Sharply painful on one exact spot |
| During running | Eases as you warm up | Worsens as you continue |
| After stopping | Settles fairly quickly | Can ache at rest and at night |
| Hopping on that leg | Uncomfortable | Usually sharply painful |
| Progress | Improves with load reduction | Keeps worsening |
Pain you can cover with one fingertip, that hurts to hop on, and that is getting worse rather than better, should be assessed and may need imaging. That combination is worth taking seriously rather than running through.
Does this sound like yours?
- Ache along the inner border of the shin, in the lower two thirds
- Worst at the start of a run, easing somewhat once warm
- Sore for hours afterwards, sometimes into the next day
- Tender to press along a stretch of the bone edge
- Started within a few weeks of increasing running, or returning after a break
- Both legs affected, which is common and points away from a fracture
The cause is nearly always the training, not the leg
People look for something wrong with their body. Usually the body is fine and the schedule was not.
The load spike. More distance, more frequency, more speed, more hills, or a new surface. The classic is going from nothing to a structured plan in a fortnight, or from treadmill to road.
Not enough recovery. Bone needs days between hard loads to remodel. Running the same volume on consecutive days gives it no opportunity.
Calf and foot weakness. Weak calves transmit more shock to the bone. This is the single most useful thing to train, and it is trainable in anyone.
Footwear changes. Particularly a sudden move to minimal shoes without a build-up period.
Low energy availability. Under-eating relative to training load impairs bone remodelling. This is common, under-recognised, and matters far more than most runners think, particularly where periods have become irregular.
Foot structure gets blamed frequently. It is a smaller factor than the internet suggests, though it is worth reading our guide to flat feet if yours have been pointed at.
What actually helps
Reduce the load below the level that provokes it, do not stop entirely. Cut distance and intensity to what you can do without symptoms during or after. Keep fitness with cycling, swimming or the cross trainer. Complete rest deconditions the bone and the calf, and you return to the same problem.
Build the calves. Calf raises, straight knee and bent knee, slow and progressed to single leg. Aim eventually for twenty clean single leg repetitions each side. This is the highest value thing on this page.
Add hip and single leg control. Single leg balance and glute work reduce the amount of shock the shin has to absorb.
Rebuild by roughly ten percent a week. Slower than you want. Increase distance or intensity, not both in the same week, and keep at least one full rest day between harder sessions.
Shorten your stride slightly. Increasing cadence by around five to ten percent reduces the load through the lower leg per step, and it is one of the few gait changes with reasonable evidence behind it.
Things worth less than they sound
Ice and anti-inflammatories relieve symptoms and change nothing underneath. Fine for comfort, not a plan.
Compression sleeves feel supportive and have little evidence of altering the outcome.
New shoes help if yours are worn out or you changed recently. Buying your way out of a training error does not work.
Stretching the calves is reasonable maintenance and is not the treatment.
What else causes pain in the same area
- Stress fracture, discussed above, which is the one to rule out
- Chronic exertional compartment syndrome, where a tight ache builds predictably at a certain distance, often with numbness, and settles within minutes of stopping
- Nerve entrapment, giving tingling rather than ache
- Referred pain from the back, which is unaffected by how far you have run
Get it assessed if
Pain is focal enough to cover with one finger, it hurts to hop on that leg, it wakes you at night, it is worsening despite reducing your running, there is numbness or pins and needles, or you have a history of stress fractures or irregular periods. Those warrant a proper look rather than another fortnight of guessing.
Otherwise most shin splints settle within four to eight weeks once the load is honest and the calves are being trained. The trap is feeling better at week three and going straight back to the volume that caused it.