EFFECTS OF TRAINING AND TAPER ON BLOOD LEUKOCYTE POPULATIONS IN COMPETITIVE SWIMMERS - RELATIONSHIPS WITH CORTISOL AND PERFORMANCE

The effects of 12 weeks of training and 4 weeks of taper on blood leuc ocyte populations and cortisol were investigated in 8 well-trained com petition swimmers. Blood samples were taken at rest in the mid-season (week 10), before taper (week 22) and after taper (week 25). Swimmers improving by more than 2 % with taper (N = 4), efficient (GE), were co mpared with swimmers improving by less than 2 % (N = 4), less efficien t (GLE). No significant changes were observed in leucocyte subpopulati ons or cortisol during training. The percentage of neutrophils decreas ed du ring taper (p < 0.05). Basophils a nd the percentage of granuloc ytes tended to decrease, while lymphocytes tended to increase. The inc rement in lymphocytes was positively related with the reduction in tra ining volume during taper (r = 0.86, p < 0.05). Cortisol levels did no t change with taper and were not related with leucocyte status and kin etics. CE swimmers had higher pre- and post-taper eosinophil counts th an GLE swimmers (p < 0.05). Lymphocyte counts in GE tended to be highe r, too. Cortisol decreased with taper in CE, while it increased in GLE . In conclusion, taper appeared to have an influence on leucocyte popu lation, which did not seem to be related with blood cortisol.