RECOMBINANT HUMAN ERYTHROPOIETIN SUPPLEMENTS IMPROVE CYCLING PERFORMANCE
Annaheim, S., Jacob, M., Krafft, A., & Boutellier, U. (2009). Effect of different rhEPO dosages on cycling performance. A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.
This study investigated increments in maximal and submaximal cycling performance at different time points and dosages of recombinant human erythropoietin (rhEPO). Ss (N = 40) were assigned to four groups differing in dosage of rhEPO administered three times a week over four-weeks (control, saline injection; low concentration, 20 IU rhEPO/kg body mass; medium concentration, 85 IU rhEPO/kg body mass, high concentration, 150 IU rhEPO/kg body mass). Maximal and submaximal cycling performances were assessed by an incremental test (maximal power output [Pmax] and maximal oxygen consumption [VO2max]) and a constant-load test (time-to-exhaustion) at 85% Pmax of the incremental test performed before rhEPO treatment.
After two weeks of rhEPO administration, no significant changes in VO2max occurred. VO2max increased after four weeks in the high and medium concentration groups. The improvement was accompanied by an increase in maximal power output for the two groups. The high and medium groups improved in time-to-exhaustion. In contrast to VO2max and Pmax, time-to-exhaustion had already increased after two weeks of rhEPO administration for the high and medium groups. Additionally, the control group improved in time-to-exhaustion by ~23.8% after four weeks.
Implication. Improvements in submaximal cycling performance (time-to-exhaustion) occur after two weeks of rhEPO administration for high and medium rhEPO concentrations. Submaximal performance is enhanced further after four weeks of rhEPO treatment where significant improvements in maximal cycling performance (VO2max, Pmax) also become apparent. This indicates that improvements in submaximal cycling performance are not only due to increased maximal cycling performance (explaining 26% of the variance of increased submaximal cycling performance). Probably other mechanisms, such as increased oxygen availability in working muscles and concomitant metabolic changes or direct effects of rhEPO on skeletal muscles, lead to more pronounced improvements in submaximal compared to maximal performance.
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