Abstract

Background: Blood flow restriction (BFR) training could be a valuable treatment to induce exercise-induced hypoalgesia (EIH) in patients with end-stage knee osteoarthritis. However, the use of BFR in these patients is poorly explored and there is no evidence about the training dosage needed. Objective: To evaluate the effect of resistance training protocols with different occlusion levels of blood flow restriction (BFR) on EIH in patients with end-stage knee osteoarthritis. Design: Crossover study. Setting: University physical exercise laboratory. Participants: 26 adults with end-stage knee osteoarthritis. Interventions: Patients performed four sets (30, 15, 15, and 15 repetitions) separated by 1-minute rests of three protocols/sessions of low-load (30% one-repetition-maximum) seated knee extensions with elastic bands and BFR: placebo (sham BFR), BFR at 40% arterial occlusion pressure (AOP) and BFR at 80% AOP. Main Outcome Measures: Pressure Pain Thresholds (PPT) and Visual Analog Scale (VAS) collected before, immediately after session, and after 10 minutes. Results: No differences in EIH were found between the different levels of BFR. However, 80% AOP protocol worsened VAS scores immediately (mean difference [MD]: −21.2 (95% confidence interval [CI] −33.9 to −8.5) while improving PPT immediately (MD affected limb: −.6 [95% CI −1.1 to −.2]); contralateral: −.6 (95% CI −1.0 to −.2]) and at 10 minutes (MD affected limb: −.6 [95% CI) −1.2 to −.1]; contralateral: −.7 [95% CI −1.1 to −.2]; and forearm: −.5 [95% CI −.9 to −.05]) post-exercise compared to baseline. Conclusions: There is no EIH difference after using different occlusion levels. EIH is modulated by pain-related psychological constructs and self-perceived health status.