Usually the adductor or hip-flexor tendons complaining about load - the early stage of a groin strain, triggered by ramping too fast, hills, sprints, or weak adductors.
The response is boring and works: back off intensity (sharp pain is a stop signal), warm up, strengthen adductors and hips (Copenhagen planks have the evidence), ramp gradually - most settle in days to weeks. The lookalikes: inguinal hernia (a bulge standing or straining, rest-pain - surgical opinion), hip joint problems (catching, clicking, shoe-and-sock trouble), sports hernia (deep sprinting pain rest does not fix), stress fracture (escalating pain, hurts hopping - stop and image).
What to do
Common questions
Why do I get twinges in my groin when running?
The running groin twinge is usually a tendon talking. The adductor group (inner thigh) and the hip flexors attach right at the groin crease, and they complain when load outpaces preparation: ramping mileage or speed too fast, hill work, sprinting without warming, weak adductors relative to the rest of the running body. The twinge is the early stage of a groin strain - and the correct response is the boring one: back off intensity (sharp pain is a stop signal, not a push-through), warm up properly, add strength work for the adductors and hips (Copenhagen planks are the evidence-backed one), and ramp back gradually - most settle in days to weeks. The lookalikes that change the answer: an inguinal hernia (a bulge in the groin that appears standing or straining, an ache that persists at rest - needs a surgical opinion rather than rest alone); a hip joint problem (pain with a catching or clicking feel, stiffness, trouble with shoes and socks - different exam); sports hernia (deep groin pain with sprinting or twisting that rest does not fully fix); and a stress fracture (pain that escalates with every run and hurts hopping - stop and get imaged). Pymander, a free AI doctor available 24/7 by text, can help you sort strain from hernia.