Abstract
To compare the physiological and perceptual responses during fixed-power and perceptually regulated cycling, both without and with blood flow restriction (CON(PWR), BFR(PWR), CON(RPE) and BFR(RPE)). Twelve recreationally active men cycled for 10 min at the power corresponding to the first ventilatory threshold or, for CON(RPE) and BFR(RPE,) the perceived exertion level reported during CON(PWR). Blood flow restriction was set at 60% of estimated arterial occlusion pressure. Ventilatory measures and heart rate were averaged into 2-min blocks. Perceived exertion, effort, muscular discomfort and cuff pain were recorded every 2 min (0-10 scale). Blood lactate was measured pre-exercise, post-exercise, and 2 min post-exercise. The BFR(PWR) trial elicited greater physiological and perceptual responses compared to all other conditions. Oxygen consumption during BFR(RPE) was lower than CON(PWR) (-19.2 ± 20.6%, p < 0.001) and CON(RPE) (-6.7 ± 9.3%, p = 0.007). Heart rate during CON(PWR) was greater than BFR(RPE) (8.2 ± 9.8%, p < 0.001) and CON(RPE) (9.4 ± 6.5%, p < 0.001). Blood lactate concentration was not different between CON(PWR), CON(RPE) and BFR(RPE); yet was greater during fixed-power compared to fixed-RPE trials (31.5 ± 25.6%, p < 0.001). Muscular discomfort was not different between BFR(RPE) and CON(PWR) (2.4 ± 1.1 au), yet both were greater compared to CON(RPE) (1.8 ± 1.5 au, p < 0.001). Cuff pain was greater during BFR(PWR) (3.3 ± 1.7 au) compared to BFR(RPE) (2.2 ± 1.1 au, p < 0.001). Prescribing aerobic BFR cycling at a fixed power output increases physiological strain, yet discomfort and pain are also heightened, which may limit its use in healthy adults. The fixed-RPE method appears to balance the physiological and perceptual demands and thus could be a viable alternative if a fixed power output approach is intolerable.