title: VO2 kinetics and metabolic contributions whilst swimming at 95, 100, and 105% of the velocity at VO2max.
abstract: A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transient VO2 kinetics responses and metabolic contributions whilst swimming at different velocities around VO2max. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity at VO2max (vVO2max) and (ii) three square wave exercises from rest to 95, 100, and 105% of vVO2max. VO2 was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (τ1--15, 18, and 16 s, A1--36, 34, and 37 mL · kg(-1) · min (-1), and Gain--32, 29, and 30 mL · min (-1) at 95, 100, and 105% of the vVO2max, resp.) but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL · min (-1), resp.). The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.). The adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception of VO2 slow component kinetics metabolic profiles.
authors.affiliation: Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450 Porto, Portugal.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Sousa
authors.affiliation: Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450 Porto, Portugal ; Porto Biomechanics Laboratory, LABIOMEP, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450 Porto, Portugal.
authors.forename: João P
authors.initials: JP
authors.lastname: Vilas-Boas
authors.affiliation: Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450 Porto, Portugal ; Porto Biomechanics Laboratory, LABIOMEP, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450 Porto, Portugal.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Fernandes
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance; D013550:Swimming