Exercise modality effect on bioenergetical performance at VO₂max intensity

Purpose: A bioenergetical analysis of different exercise modes near maximal oxygen consumption (VO_2max) intensity is scarce, hampering the prescription of training to enhance performance. We assessed the time sustained in swimming, rowing, running, and cycling at an intensity eliciting VO_2max and determined the specific oxygen uptake (VO₂) kinetics and total energy expenditure (E_tot-tlim). Methods: Four subgroups of 10 swimmers, 10 rowers, 10 runners, and 10 cyclists performed (i) an incremental protocol to assess the velocity (vVO_2max) or power (wVO_2max) associated with VO_2max and (ii) a square wave transition exercise from rest to vVO_2max/wVO_2max to assess the time to voluntary exhaustion (Tlim-100%VO_2max). The VO₂ was measured using a telemetric portable gas analyzer (K4b², Cosmed, Rome, Italy) and VO₂ kinetics analyzed using a double exponential curve fit. E_tot-tlim was computed as the sum of its three components: aerobic (Aer), anaerobic lactic (Ana_lac), and anaerobic alactic (Ana_alac) contributions. Results: No differences were evident in Tlim-100% VO_2max between exercise modes (mean ± SD: swimming, 187 ± 25; rowing, 199 ± 52; running, 245 ± 46; and cycling, 227 ± 48 s). In contrast, the VO₂ kinetics profile exhibited a slower response in swimming (21 ± 3 s) compared with the other three modes of exercise (rowing, 12 ± 3; running, 10 ± 3; and cycling, 16 ± 4 s) (P ± 0.001). E_tot-tlim was similar between exercise modes even if the Ana_lac contribution was smaller in swimming compared with the other sports (P < 0.001). Conclusion: Although there were different VO₂ kinetics and ventilatory patterns, the Tlim-100%VO_2max was similar between exercise modes most likely related to the common central and peripheral level of fitness in our athletes.