title: VO2 kinetics during heavy and severe exercise in swimming.
abstract: The purpose of this study was to describe the VO2 kinetics above and below respiratory compensation point (RCP) during swimming. After determination of the gas-exchange threshold (GET), RCP and VO(2max), 9 well-trained swimmers (21.0 ± 7.1 year, VO(2max)=57.9 ± 5.1 ml.kg (- 1).min (- 1)), completed a series of "square-wave" swimming transitions to a speed corresponding to 2.5% below (S - 2.5%) and 2.5% above (S+2.5%) the speed observed at RCP for the determination of pulmonary VO2 kinetics. The trial below (~2.7%) and above RCP (~2%) was performed at 1.28 ± 0.05 m.s (- 1) (76.5 ± 6.3% VO(2max)) and 1.34 0.05 m.s (- 1) (91.3 ± 4.0% VO(2max)), respectively. The time constant of the primary component was not different between the trials below (17.8 ± 5.9 s) and above RCP (16.5 ± 5.1 s). The amplitude of the VO(2)slow component was similar between the exercise intensities performed around RCP (S - 2.5%=329.2 ± 152.6 ml.min (- 1) vs. S+2.5%=313.7 ± 285.2 ml.min (- 1)), but VO(2max) was attained only during trial performed above RCP (S-2.5%=91.4 ± 5.9% VO(2max) vs. S+2.5%=103.0 ± 8.2% VO(2max)). Thus, similar to the critical power during cycling exercise, the RCP appears to represent a physiological boundary that dictates whether VO(2) kinetics is characteristic of heavy- or severe-intensity exercise during swimming.
authors.affiliation: Human Performance Laboratory, Physical Education, Rio Claro, Brazil.
authors.forename: D M
authors.initials: DM
authors.lastname: Pessoa Filho
authors.forename: F B
authors.initials: FB
authors.lastname: Alves
authors.forename: J F
authors.initials: JF
authors.lastname: Reis
authors.forename: C C
authors.initials: CC
authors.lastname: Greco
authors.forename: B S
authors.initials: BS
authors.lastname: Denadai
mesh_terms: D000293:Adolescent; D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D056352:Athletes; D001642:Bicycling / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D013550:Swimming / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen