Shin Splints (Medial Tibial Stress Syndrome)

What it is

MTSS is exercise-induced pain along the inner (medial) edge of the shinbone. A 2025 clinical reference describes diffuse tenderness or mild swelling along that border, and says the pain typically begins as mild, activity-related discomfort and can become more persistent if training continues without modification¹. That is the reason to act on the first mild ache and not to wait.

Who gets it

Two older meta-analyses, one from 2013 in runners and one from 2017 in active people, found associations with female sex, a previous bout or running injury, a higher body mass index and a greater navicular drop (how far the arch of the foot lowers when standing), and the runner analysis also found fewer years of running experience. Both say risk factors differ between men and women²³. These are observational findings, and most of the factors are not ones you can change quickly. A previous bout and a short running history are the ones that say to build up slowly.

Load is the factor a runner controls. In 5,205 runners followed for 18 months, injuries of any kind were more common when a session was more than 10% longer than the longest run of the previous 30 days⁴. That study was not specific to shin splints.

What was tried

The treatment research is thin and mixed. In a 2017 trial of 28 active adults with MTSS, a standard dose of shockwave therapy was not more effective than a sham dose at improving pain or running distance, and the authors note the sham dose may have had a clinical effect⁵. A 2024 systematic review of shockwave across sports injuries concluded, from the highest-level studies, that it may be effective as an adjunct to exercise treatment in MTSS, and called for more high-level research⁶. No single treatment has strong support, which is why load comes first.

Running with it

Because load is the part you control, running with shin splints is mostly a matter of dosing it:

• A physical therapist's rule for returning runners: pain stays at 3 out of 10 or lower (4 at most) while you run and is stable or improving over the weeks, you stop the run if it climbs above that, and the shin is back to its usual level within 24 hours of finishing. A limp, or any change in how you move, is a stop. Your clinician may set a different limit. The guide on pain versus soreness covers the difference between an ache to run through and pain to stop for.
• Replace the running you cut with aerobic work that adds no lower-body impact, at an easy conversational effort, which is zone 2 in a five-zone model.
• Return gradually once it settles, and keep the load that caused it from coming back all at once: no run much longer than your longest run of the last 30 days. Bring hills and fast running back last.
• Ask a clinician to look at your foot, hip and running pattern, since the risk factors above vary from person to person.

The stress-fracture warning

The 2025 clinical reference calls MTSS an early stage within a continuum of tibial stress injuries and says prolonged cases can raise susceptibility to tibial stress fractures¹. A clinician makes that call. Treat these as warning signs: a diffuse shin ache that becomes sharp, pinpoint pain, or pain that persists at rest or at night means stop running and get it evaluated. The guide on stress fractures covers what happens next.

When to see a professional

See a sports-medicine professional if shin pain is not easing after a couple of weeks of reduced running, keeps returning when you build up, or you are unsure of the cause. Seek prompt care for pinpoint bone tenderness, pain at rest or at night, or pain after a specific injury. A possible stress fracture needs proper diagnosis and a managed return.