Expired air was collected continuously throughout each exhaustive trial using an online metabolic system calibrated
prior to each test with a span gas mixture of 16% O2 and 5% CO2 and a 3 L syringe (Hans Rudolph Inc., Kansas City, MO,
USA).
Gas exchange variables such as oxygen uptake (V_ O2) were recorded breath by breath and later averaged over 30
seconds. Heart rate (HR), collected via telemetry (Polar Electro, Polar Beat Oy, Kempele, Finland), and RPE40 were recorded in the final 15 seconds of each exercise bout. V_ O2peak was accepted as the highest V_ O2 averaged over 30 seconds