Overtraining syndrome: a guide to diagnosis, treatment, and prevention.

Overtraining syndrome is a common cause of underperformance in athletes. Symptoms such as persistent fatigue, muscle soreness, reduced coordination, weight loss, mood changes, and frequent illness may accompany performance decrements, but they may also be signs of underlying medical conditions. Reliable and practical diagnostic laboratory tests for overtraining have not yet been identified. Clinicians can prescribe relative or complete rest and strive to identify and correct the training, nutritional, and psychosocial factors that contributed to the athlete's condition.