Introduction and objective: Delta efficiency (DE) and oxygen uptake kinetics (K O 2 ) are influenced by muscle metabolic parameters and oxygen transport. The aim of this study was to determine the difference in DE and K O 2 in three effort intensities in both genders. Methods: Fifty-six subjects (26 women) were submitted to a graded maximal exercise test (GXT) on cycle ergometer to determine the maximum oxygen uptake ( O 2max ), maximal power output (W max ), anaerobic threshold (AT) and respiratory compensation point (RCP). The AT and RCP were determined using the V-slope and E / O 2 methods; the RCP using the relationship O 2 versus E both by two investigators. The DE and K O 2 have been considered as a slope between O 2 versus Watts and O 2 versus time (s), respectively, from the beginning of test until AT (S 1 ), from AT to RCP (S 2 ) and from RCP to O 2max (S 3 ), determined by linear regression analysis. Results: Regarding DE, significant differences were observed between S 1 versus S 2 (p = 0.001), S 1 versus S 3 (p = 0.001) and S 2 versus S 3 (p = 0.006). There was no significant difference (p = 0.060) or interaction (p = 0.062) between men and women. For K O 2 , significant differences were observed between S 1 versus S 3 (p = 0.001) and S 2 versus S 3 (p = 0.001) in both genders. Significant differences (p = 0.001) and interaction (p = 0.006) were observed between men and women, in the last parameter. Conclusions: DE decreases with increasing intensity of power output, but there are no differences when comparing men and women. On the other hand, women present faster K O 2 than men.

No abstract