Acute Responses to Cycling Exercise With Blood Flow Restriction During Various Intensities.

ABSTRACT Lauver, JD, Moran, A, Guilkey, JP, Johnson, KE, Zanchi, NE, and Rotarius, TR. Acute responses to cycling exercise with blood flow restriction during various intensities. J Strength Cond Res XX(X): 000-000, 2021-The purpose of this study was to investigate the acute physiological responses during cycling at various intensities with blood flow restriction (BFR). Participants (N = 9; V[Combining Dot Above]O2peak = 36.09 ± 5.80 ml·kg-1·min-1) performed 5 protocols: high-intensity (HIGH), control (CON-90), 90% of ventilatory threshold (VT) work rate with BFR (90-BFR), 70% of VT with BFR (70-BFR), and 30% V[Combining Dot Above]O2peak with BFR (30-BFR). Protocols consisted of five 2-minute work intervals interspersed with 1-minute recovery intervals. Blood flow restriction pressure was 80% of limb occlusion pressure. V[Combining Dot Above]O2, muscle excitation, tissue oxygen saturation (StO2), discomfort, and level of perceived exertion (RPE) were assessed. Muscle excitation was higher during HIGH (302.9 ± 159.9 %BSL [baseline]) compared with 70-BFR (99.7 ± 76.4 %BSL) and 30-BFR (98.2 ± 70.5 %BSL). StO2 was greater during 90-BFR (40.7 ± 12.5 [INCREMENT]BSL), 70-BFR (34.4 ± 15.2 [INCREMENT]BSL), and 30-BFR (31.9 ± 18.7 [INCREMENT]BSL) compared with CON-90 (4.4 ± 11.5 [INCREMENT]BSL). 90-BFR (39.6 ± 12.0 [INCREMENT]BSL) resulted in a greater StO2-Avg compared with HIGH (20.5 ± 13.8 [INCREMENT]BSL). Also, HIGH (23.68 ± 5.31 ml·kg-1·min-1) resulted in a greater V[Combining Dot Above]O2 compared with 30-BFR (15.43 ± 3.19 ml·kg-1·min-1), 70-BFR (16.65 ± 3.26 ml·kg-1·min-1), and 90-BFR (18.28 ± 3.89 ml·kg-1·min-1); 90-BFR (intervals: 4 = 15.9 ± 2.3; intervals: 5 = 16.4 ± 2.5) resulted in a greater RPE compared with 30-BFR (intervals: 4 = 13.3 ± 1.4; intervals: 5 = 13.7 ± 1.7) during intervals 4 and 5. These results suggest that when adding BFR to various intensities of aerobic exercise, consideration should be given to peak work and VT to provide a balance between high local physiological stress and perceptual responses.