Some haematological characteristics of competitive swimmers.

Some basic haematological characteristics of a group of competitive swimmers were compared with haematological "normal standards" and with a "control" group of non-athletes, unmatched for age. In the women, the values for red blood cell count, haemoglobin concentration, and mean red cell volume for both the swimmers and the controls were not significantly different from the normal standards. In the groups of men, both swimmers and controls, red cell counts were significantly lower than the normal standard values, although individual values lay within the "normal range" (mean ± 2 standard deviations). The ranges of the values for individuals % ere found to be narrow. There were no significant differences between these ranges over periods of five consecutive weeks and five consecutive months. Relatively large changes in results for individuals could occur before the results would be considered abnormal, that is, before the results fall outside the "normal range". Early detection of changes may perhaps be facilitated if the range of values for individual athletes is determined by monitoring. INTRODUCTION Recent improvements in performance in most athletic and swimming events are probably due in part to both careful early selection and intensive training. In swimming, prepubertal children who show outstanding ability and potential often undertake daily rigorous training routines. However, the characteristics of these exceptional people and the effects of the training they undertake are poorly documented (Cunningham and Eynon, 1975). *Present Address: Department of Anatomy, University of Alberta, Edmonton, Canada. This study was undertaken to investigate some basic haematological characteristics of a group of intensively trained competitive swimmers. The values obtained were compared with both normal standards and with values for a control group. If the factors responsible for improvements in per. formance can be defined then it may be possible to identify those which limit performance, not only in elite performers but also in less able individuals. SUBJECTS AND METHODS The swimmers (19 boys, age 12.5-19.8 years, mean 15.4 ± 2.3, and 19 girls, age 12.9-18.9 years, mean 15.0 ± 1.8) were members of the City of Manchester 238 group.bmj.com on April 13, 2017 Published by http://bjsm.bmj.com/ Downloaded from