Mackinnon, L. T., Hooper, S. L., Jones, S., Gordon, R. D., & Bachmann, A. W. (1997). Hormonal, immunological, and hematological responses to intensified training in elite swimmers. Medicine and Science in Sports and Exercise, 29, 1637-1654.

Elite swimmers (M = 8; F = 16) were subjected to progressively intensified training over a four-week period. Symptoms of over-reaching were identified in eight Ss (decrements in performance, high ratings of fatigue, log book records of poor adaptation).

There were no differences between adapting and over-reached swimmers for concentrations of plasma norepinephrine, cortisol, testosterone, testosterone-cortisol ratio, peripheral blood leukocyte and differential counts, neutrophil-lymphocyte ratio, CD4-CD8 ratio, serum ferritin, and blood hemoglobin concentrations, erythrocyte number, hematocrit, and mean red cell count. Mean red cell count increased in both groups during the observation period suggesting increased red cell turnover. Urinary norepinephrine excretion was the only variable to distinguish between the two groups of athletes. Low levels were observed 2-4 weeks prior to the onset of over-reaching suggesting that it might be a symptom that signals failing adaptation.

Implication. Blood analyses and hormonal factors are not sensitive to declines in performance due to a failure to cope with intensified training.

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