Groin pain is a condition with a high prevalence in young Australian football players. It is considered that early identification of this condition allows for optimal management. Eighty-six players from two elite under-age Australian football sides were screened weekly for hip adductor muscle strength, using a hand-held dynamometer and for the onset of groin pain. The maximum variation in the average hip adductor muscle strength values of the sample was a 2.6% decrease from baseline in week 7 of the study. Twelve players (14% of the sample studied) reported groin pain for two consecutive weeks and were considered to have an onset of groin injury. The mean hip adductor muscle strength of these players was decreased significantly from baseline by an average of 11.75+/-2.50% at the week of pain onset (F=264.76 (1,11), p<0.001), and 5.82+/-5.16% in the week preceding the onset of pain (F=14.03 (1,10), p=0.004). These results confirm that hip adductor muscle strength is decreased both preceding and during the onset of groin injury in elite under-age Australian footballers.