To evaluate the hypothesis that groin pain at isometric hip adduction may not be caused by adductor tendinitis. Symptoms and signs in a cross-sectional analysis. Multicenter primary care institutes. Athletes with pain in the groin(s), provoked by playing sports, with a duration of complaints for at least 1 month and pain provocation on isometric adduction of the hips. Data on medical history and symptoms were collected. Pain provocation tests and strength measurements were performed. A pelvic belt was used to investigate its influence on pain provocation and strength. Site of the pain, duration of the complaints, severity of the pain, hip adduction force, pain at isometric hip adduction, restriction to perform active straight leg raising, influence of a pelvic belt on pain and strength of isometric hip adduction and straight leg raising. Groin pain was bilateral in 41%; pain was also located at the posterior aspect of the pelvis in 32%; Active Straight Leg Raise (ASLR) test was positive in 39%. When tested with a pelvic belt, the weakness of ASLR improved in all with a positive ASLR, hip adduction force increased significantly in 39% and pain at forceful isometric hip adduction decreased in 68%. Groin pain at isometric hip adduction may not be caused by adductor tendinitis in a large proportion of athletes with adduction-related groin pain. The results suggest that adduction-related groin pain with a positive belt test may be treated by stabilization of the pelvis.