Overreaching results in short-term decreases of performance quality, whereas overtraining results in long-term decreases (Meeusen et al., 1).
Generally, the symptoms of overtraining syndrome are recognized as more detrimental than the syndrome itself (Meeusen et al., 5). These symptoms include fatigue, performance decline, and mood disturbance (Meeusen et al., 5). Unfortunately, there is not substantial enough evidence to back this claim up (5).
Triggers of overtraining syndrome (OTS) can be anything from increased load of training to monotony of training variety to an overabundance of competitions (Meeusen et al., 6).
Biochemical and hormone indicators of OTS are unreliable at best (Meeusen et al., 8-11).
Psychological indicators of OTS are more reliable than physiological ones, but are not completely accurate due to incompletion of psychological surveys (Meeusen et al., 13).
Meeusen, Romain, et al. “Prevention, Diagnosis and Treatment of the Overtraining Syndrome: Joint Consensus Statement of the European College of Sport Science (ECSS) and the American College of Sports Medicine (ACSM).” European Journal of Sport Science, vol. 13, no. 1, 2013, pp. 1–24., doi:10.1080/17461391.2012.730061.
