Underperformance syndrome

It has been known in sports medicine that too much training can bring on a condition known as overtraining or underperformance syndrome (UPS). Symptoms include sleep disturbance, increased perception of effort, decreased effectiveness of the immune system and unexpected poor performance in training or in competition. At present, there is no satisfactory biochemical or physiological explanation for the syndrome. Identification of a biochemical marker... 

The unexplained underperformance syndrome occurs in cycling, rowing, swimming and middle- and long-distance runners. A high proportion of elite adiletes have experienced it. In contrast, it appears much less frequently in adiletes who participate in explosive sports. 

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