VO(2) Kinetics and Metabolic Contributions Whilst Swimming at 95, 100, and 105% of the Velocity at VO(2 max)

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(2max⁡). 12 trained male swimmers performed (i) an incremental protocol to determine the velocity at VO(2max⁡) (vVO(2max⁡)) and (ii) three square wave exercises from rest to 95, 100, and 105% of vVO(2max⁡). 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 vVO(2max⁡), 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.