title: The effects of short recovery duration on VO2 and muscle deoxygenation during intermittent exercise.
abstract: This study compared the oxygen uptake (VO(2)) and muscle deoxygenation (∆HHb) of two intermittent protocols to responses during continuous constant load cycle exercise in males (24 year ± 2, n = 7). Subjects performed three protocols: (1) 10 s work/5 s active recovery (R), R at 20 W (INT1): (2) 10 s work/5 s R, R at moderate intensity (INT2); and (3) continuous exercise (CONT), all for 10 min, on separate days. The work rate of CONT and the 10 s work of INT1 and INT2 were set within the heavy intensity domain. VO(2) and ∆HHb data were filtered and averaged to 5 s bins. Average VO(2) (80-420 s) was highest during CONT (3.77 L/min), lower in INT2 (3.04 L/min), and lowest during INT1 (2.81 L/min), all (p < 0.05). Average ∆HHb (80-420 s) was higher during CONT (p < 0.05) than both INT exercise protocols (CONT; 25.7 ± 0.9 a.u. INT1; 16.4 ± 0.8 a.u., and INT2; 15.8 ± 0.8 a.u.). The repeated changes in metabolic rate elicited oscillations in ΔHHb in both intermittent protocols, whereas oscillations in VO(2) were only observed during INT1. The greater ΔHHb during CONT suggests a reduction in oxygen delivery compared to oxygen consumption relative to INT. The higher VO(2) for INT 2 versus INT 1 and similar ΔHHb during INT suggests an increase in oxygen delivery during INT 2. Thus the different demands of INT1, INT2, and CONT protocols elicited differing physiological responses to a similar heavy intensity power output. These intermittent exercise models seem to elicit an elevated O(2) delivery condition compared to CONT.
authors.affiliation: Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, Thames Hall, London, ON N6A 3K7, Canada. gbellfry@uwo.ca
authors.forename: Glen R
authors.initials: GR
authors.lastname: Belfry
authors.forename: Donald H
authors.initials: DH
authors.lastname: Paterson
authors.forename: Juan M
authors.initials: JM
authors.lastname: Murias
authors.forename: Scott G
authors.initials: SG
authors.lastname: Thomas
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D055815:Young Adult