VO 2 kinetics and metabolic contributions whilst swimming at 95, 100, and 105% of the velocity at VO 2 max

Abstract

A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transient VO 2 kinetics responses and metabolic contributions whilst swimming at different velocities around VO 2 max. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity at VO 2 max (v VO 2 max) and (ii) three square wave exercises from rest to 95, 100, and 105% of v VO 2 max. VO 2 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 (τ 1 - 15, 18, and 16 s, A 1 - 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 v VO 2 max, 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 O 2 delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception of VO 2 slow component kinetics metabolic profiles. © 2014 Ana C. Sousa et al.