Guo, H., Lu, Y., & Stager, J. M. (2010). The difference in red blood cell indices between elite female distance and sprint swimmers. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 16–19, 2010.

This study determined if differences in red blood cell indices existed between elite female distance (N = 11; 400 and 800 m events) and sprint (N = 11; 100 and 200 m events) swimmers. All Ss were trained at the same facility. Red blood cell count, hematocrit, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and red blood cell volume distribution width were measured every Monday morning, before the first training session over a one-year period from August, 2007 until July, 2008. Due to objective limits (such as subject unavailability or technical error of instruments), the number of samples obtained was 477 in the distance group and 459 in the sprint group.

The distance group had significantly higher values of hematocrit, hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin. Significantly lower values of mean corpuscular hemoglobin concentration and red blood cell volume distribution width were recorded in the distance group. There were no differences between groups for red blood cell count.

Implication. Red blood cell count values in both groups were at an advantageous level for oxygen transportation in the blood. Higher values of hematocrit, hemoglobin, and mean corpuscular hemoglobin in the distance group suggest a potential for greater oxygen flow to meet the presumably greater use of oxygen in active skeletal muscles during distance swimming. Higher values of mean corpuscular volume in the distance group probably indicated a larger proportion of young red blood cells, which had more deformability which facilitated their passage through capillaries. Higher values of mean corpuscular hemoglobin concentration demonstrated that a larger proportion of red blood cells in the sprint group were aging and atrophic. Atrophy also varies the shapes of red blood cells resulting in the sprint swimmers recording higher values of red blood cell volume width.

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