Can individuals be taught to sense the degree of vascular occlusion? a comparison of methods and implications for practical blood flow restriction

The study objective was to determine whether subjects could be conditioned to a relative blood flow restriction pressure in the lower body and compare 2 separate conditioning methods (unconstrained vs. constrained). Thirty-five subjects completed 4 visits, involving measurements for arterial occlusion and pressure estimations at 5 minutes and 24 hours after conditioning. The constrained method involved applying 40% of measured arterial occlusion 11 times, along with 10% above and below this pressure. The unconstrained method was time-matched, involving a series of inflations to 40% arterial occlusion for 12 seconds and then deflated for 22 seconds. Data are presented as mean differences (95% credible interval) unless otherwise noted. The absolute error between conditioning methods was found to be similar at 5 minutes (−1.1 [−5.9, 3.7] mm Hg) and 24 hours (−2.4 [−7, 2.2] mm Hg) after conditioning. The constant error differed between methods at 5 minutes [−8.2 (−14.4, −1.9) mm Hg] but was similar at 24 hours (−2.5 [−8.5, 3.6] mm Hg; H0: 0.680; H1: 0.068; and H2: 0.252) after conditioning. The bias and 95% limits of agreement for the unconstrained method were −3.9 (−33.8, 25.9) mm Hg at 5 minutes and −2.9 (−32, 26.1) mm Hg at 24 hours. The agreement for the constrained method was 4.2 (−28, 36.5) mm Hg at 5 minutes and −0.54 (−37.3, 36.2) mm Hg at 24 hours. Conditioning methods produced similar levels of absolute error, indicating that either method may offer a viable means of pressure application. Most estimates were between 20 and 60% of arterial occlusion pressure. Additional conditioning sessions may be needed to narrow this range at the individual level.