Abstract

CERQUEIRA, Lucenildo S; NOGUEIRA, Fernando S; CARVALHO, Joyce  and  POMPEU, Fernando A.M.S. Oxygen uptake kinetics and delta mechanical efficiency response of men and women at different exercise intensities. Rev Bras Med Esporte [online]. 2011, vol.17, n.4, pp. 274-278. ISSN 1517-8692.  http://dx.doi.org/10.1590/S1517-86922011000400013.

ABSTRACT INTRODUCTION AND OBJECTIVE:Delta efficiency (DE) and oxygen uptake kinetics (K₂) are influenced by muscle metabolic parameters and oxygen transport. The aim of this study was to determine the difference in DE and K₂ 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 ( _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 / ₂ methods; the RCP using the relationship ₂versus _E both by two investigators. The DE and K₂ have been considered as a slope between ₂versus Watts and ₂versus time (s), respectively, from the beginning of test until AT (S₁), from AT to RCP (S₂) and from RCP to _2max (S₃), determined by linear regression analysis. RESULTS: Regarding DE, significant differences were observed between S₁ versus S₂ (p = 0.001), S₁ versus S₃ (p = 0.001) and S₂ versus S₃ (p = 0.006). There was no significant difference (p = 0.060) or interaction (p = 0.062) between men and women. For K₂, significant differences were observed between S₁ versus S₃ (p = 0.001) and S₂ versus S₃ (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 K₂than men

Keywords : ergospirometry; effort test; ₂ e _2máx slow component.