To evaluate a functional neuromuscular training program focusing on strength, endurance, postural control, and agility, 26 patients with a rupture of the anterior cruciate ligament (ACL) diagnosed late were examined before starting a training period and then followed for three years. During the study period, four of the patients had an ACL reconstruction. Twenty-two patients treated without surgery were satisfied with the improvement in their knee function and activity level after three to six months of physiotherapy. Compliance with the rehabilitation program was good and the improvement achieved on completion of the training period was maintained for three years in this group of recreational sportsmen and women. Quadriceps strength, functional knee score, activity level, and functional performance were all improved after training and were maintained during the follow-up period.