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Special Topics on Overtraining Syndrome (OTS)/Paradoxical Deconditioning Syndrome (PDS)


Despite the massive popularity of the term “overtraining syndrome,” the vast majority of sports-related health providers are unaware of the correct definition, characteristics, and diagnosis of overtraining syndrome (OTS). While the sine qua non criteria of decreased performance unexplained by underlying conditions is unfamiliar and not employed by many, characteristics that although may be present in OTS should not be considered for its diagnosis, including the occurrence of infections, prolonged or exacerbated muscle soreness, and joint injuries or use of non-validated markers, such as cortisol-to-testosterone ratio or creatine kinase (CK), are inappropriately though highly used to designate OTS. Consequently, almost 90% of the athletes suspected for OTS are excluded if appropriate criteria is employed.

Hence, most of the athletes claimed to present OTS are actually “pseudo-OTS” or “OTS-like” conditions. Altogether, actual OTS, paradoxical deconditioning syndrome (PDS), overreaching states, relative energy deficiency of the sport (RED-S), burnout syndrome of the athlete (BSA), “pseudo-OTS,” or “OTS-like” conditions are so similar in terms of pathophysiology and underlying mechanisms between them, in a way that they can be clustered into a sole condition, as a sort of “impaired athlete syndrome” (IAS), that encompasses all sorts of events that prevent athlete from training at full potential.

The use of deconditioning and hypometabolism are neologisms that have been proposed to describe two complex processes recently identified that are better understood with the use of these single-word expressions. The expression “deconditioning” is designated to describe a loss of the conditioning processes that athletes undergo. The neologism “hypometabolism” describes the result of different processes that occurs diffusely of forced mitigation of the metabolism. Maladaptation is an expression designated for forced adaptations to maintain survival and functioning, but which are highly dysfunctional, and lead to further and more complex diseases.

The harms of human attempts to become robot machines in terms of high simultaneous physical, social, athletic, financial, intellectual, and sexual performances, leading to multiple deprivations that are consistently neglected in the sake of the supposed “perfection”, eventually led to the current epidemic of burnout syndrome. Current overtraining syndrome could perhaps be understood as the burnout syndrome when manifested in athletes. In both cases, atypical abnormalities in the endocrine, metabolic, muscular, inflammatory, immunologic, neurologic, and autonomic systems occur not so distinctly between them.

In common, low energy availability (LEA) is the fundamental underlying pathogenic environment that leads to multiple interrelated conditions including relative energy deficiency of the sport (RED-S), OTS, burnout syndrome of the athlete (BSA), burnout syndrome, and other burnout-related conditions.

The (energy-deprived derived) paradoxical deconditioning syndrome (PDS) better described the current manifestations of OTS, once OTS goes beyond excessive training. However, in common, all cases presented LEA as a triggering factors and eventually lead to PDS, irrespective of overtraining. Also, the term PDS describes within one expression the key pathogenic path of OTS/PDS.


  • Pseudo-OTS
  • Female triad syndrome
  • Overtraining syndrome
  • OTS
  • OT
  • Paradoxical deconditioning syndrome
  • PDS
  • Overreaching
  • Non-functional overreaching
  • NFOR
  • Functional overreaching
  • FOR
  • Burnout of the athlete
  • BSA
  • Relative energy deficiency of the sport
  • RED-S
  • Underperformance
  • Underperformance syndrome
  • Unexplained underperformance syndrome
  • Endocrinology of the physical activity and sport
  • Sports endocrinology
  • Endocrine and Metabolic Responses on Overtraining Syndrome study
  • EROS
  • Burnout
  • Hypometabolism
  • Deconditioning
  • Sports medicine
  • Sports science

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Cadegiani, F. (2020). Special Topics on Overtraining Syndrome (OTS)/Paradoxical Deconditioning Syndrome (PDS). In: Overtraining Syndrome in Athletes. Springer, Cham.

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