RESTING WHOLE-BLOOD VISCOSITY OF ELITE ROWERS IS RELATED TO PERFORMANCE

This study investigated the relationships between resting whole blood viscosity (WBV), haemoglobin concentration (HGB), haematocrit (HCT), a nd performance in 25 highly-trained national squad rowers (11 women an d 14 men). The WBV and HGB were measured at rest prior to a 2500 m sim ulated race on a Concept rowing ergometer when performance (P) was mea sured by average velocity. A group of 12 rowers were measured on just one occasion, another 11 were measured twice with an intervening 5 wee ks of continued training and 2 were measured three times, the third te st after another 4 weeks. Regression analyses making simultaneous use of both intra- and interindividual data indicated a significant invers e relationship between P and WBV (at both high and low shear rates), a relationship which was strengthened after statistically controlling f or the effects of HGB, this effect being slightly more significant tha n HCT. A significant positive regression also emerged between P and HG B, but only after statistically controlling for the influence of WBV a t high shear rate. Overall, stronger relationships were demonstrated i n the male rowers compared with the female. These data, in the light o f previous evidence that fitter people tend to have lower WBV, would i ndicate that blood theology unrelated to HGB (or HCT) is related to pe rformance in relatively homogeneous and already highly-trained athlete s.