Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/53406
Title: Determinants of VO2 kinetics at high power outputs during a ramp exercise protocol
Authors: Serrano, AL
Lucía, Alejandro
Rivero, José Luis L
Pérez, Margarita
L. Serrano, Antonio 
Calbet, José A L 
Santalla, Alfredo
Chicharro, José L.
UNESCO Clasification: 241106 Fisiología del ejercicio
Keywords: EMG
FIBER
MUSCLE BIOPSY
FIBER RECRUITMENT
LACTATE, et al
Issue Date: 2002
Publisher: 0195-9131
Journal: Medicine and Science in Sports and Exercise 
Abstract: PURPOSE:To determine the relationship between the additional, nonlinear increase in oxygen uptake (Delta VO(2)) that occurs at high power outputs during a ramp cycle ergometer test, on one hand; and possible explanatory mechanisms of the phenomenon, such as cardiorespiratory work, blood lactate, fitness level, or muscle fiber distribution, on the other. METHODS:Ten healthy, sedentary young adults (age (mean +/- SEM), 22 +/- 1 yr) were chosen as subjects. A muscle biopsy specimen was taken from the vastus lateralis of the right leg to determine fiber type distribution by immunohistochemical identification of myosin heavy chain (MHC) isoforms. During the ramp tests (power output increases of 5 W every 15-s interval), the ventilatory threshold (VT) and lactate threshold (LT) were measured. We defined Delta VO(2) as the difference between "true" VO(2) values observed at the maximal power output (VO(2)obs) and those expected (VO(2)exp) from the previous linear VO2:power output relationship below the VT. RESULTS:A nonlinear increase was observed in VO2 (Delta VO(2) = 239 +/- 79 mL x min(-1), P < 0.05 for VO(2)obs vs VO(2)exp), which was significantly correlated with the percentage of type IIX fibers (r = 0.80, P < 0.05). No other correlations were found between Delta VO(2) and possible explanatory mechanisms. CONCLUSION:A greater percentage of type IIX fibers is associated with a higher excess VO(2) at high power outputs (above VT).
URI: http://hdl.handle.net/10553/50984
ISSN: 0195-9131
DOI: 10.1097/00005768-200202000-00022
Source: Medicine And Science In Sports And Exercise[ISSN 0195-9131],v. 34 (2), p. 326-331
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