Mujika, I., Padilla, S., Geyssant, A., & Chatard, J.C. (1997). Hematological responses to training and taper in competitive swimmers: Relationships with performance. Archives of Physiology and Biochemistry, 105(4), 379-385.

This study monitored hematological changes and assessed the relationships between hematological variables and competition performance during 12 weeks of intense training and 4 weeks of taper in highly trained competitive swimmers (N = 8).

Venous blood samples were obtained in the mid-season (wk 10), before taper (wk 22) and after taper (wk 26). Ss participated in actual competitions within one week of each blood testing. Comparisons were made between Ss who improved performance with taper by more than 2% (n = 4) or less than 2% (n = 4).

Hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) increased significantly during training. MCH and MCHC decreased during taper, while serum iron tended to increase (p = 0.07). Improvement in performance during taper was positively correlated with post-taper red cell count (r = 0.83, p < 0.05). Ss who improved by more than 2% had higher pre- and post-taper red cell count, and post-taper Hb and hematocrit.

Intense training and taper appeared to influence the hematological status and performance capacity of the swimmers.

Implication. Contrary to what other studies have shown this investigation revealed a relationship between blood factors and improved performance after tapering in swimmers. It is likely that other factors not investigated here intervened to produce the performance change supporting the concept of performance improvements after taper being caused by a complexity of mechanisms rather than a few simple ones.

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