Neuromuscular Responses and Perceptions of Health Status and Pain-Related Constructs in End-Stage Knee Osteoarthritis During Resistance Training With Blood Flow Restriction.

ABSTRACT: Ogrezeanu, DC, López-Bueno, L, Sanchís-Sánchez, E, Carrasco, JJ, Cuenca-Martínez, F, Suso-Martí, L, López-Bueno, R, Cruz-Montecinos, C, Martinez-Valdes, E, Casaña, J, and Calatayud, J. Neuromuscular responses and perceptions of health status and pain-related constructs in end-stage knee osteoarthritis during resistance training with blood flow restriction. J Strength Cond Res 38(4): 762-772, 2024-We aimed to evaluate the neuromuscular responses and their relationship with health status, kinesiophobia, pain catastrophizing, and chronic pain self-efficacy in patients with end-stage knee osteoarthritis during acute resistance training with different levels of blood flow restriction (BFR). Seventeen patients with end-stage knee osteoarthritis participated in 3 experimental sessions separated by 3 days, performing 4 sets of knee extensions with low load and 3 levels of concurrent BFR performed in a random order: control (no BFR), BFR at 40% arterial occlusion pressure (AOP), and BFR at 80% AOP. Normalized root-mean-square (nRMS), nRMS spatial distribution (centroid displacement, modified entropy, and coefficient of variation), and normalized median frequency (nFmed) were calculated from the vastus medialis (VM) and lateralis (VL) using high-density surface electromyography. Subjects were asked to report adverse effects after the sessions. In the VM, nRMS was higher with 80% AOP than with 40% AOP ( p = 0.008) and control ( p < 0.001), whereas there were no differences between conditions in the VL. Normalized root-mean-square also showed an association with pain catastrophizing, chronic pain self-efficacy, and health status (VM: -0.50, 0.49, -0.42; VL: -0.39, 0.27, -0.33). Spatial distribution varied between conditions but mostly in the VL. Overall, nFmed did not vary, with only a slight increase in the VL with 40% AOP, between set 3 and 4. BFR during knee extensions at 80% AOP increases VM activity and VL amplitude distribution more than 40% AOP and control. Importantly, muscle activity increases are modulated by pain catastrophizing, chronic pain self-efficacy, and health status in these patients, and kinesiophobia seems to especially modulate entropy.

Exercise-induced hypoalgesia with end-stage knee osteoarthritis during different blood flow restriction levels: Sham-controlled crossover study.

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.

Safety, feasibility, and neuromuscular activity of acute low-load resistance exercise with or without blood flow restriction in patients with severe hemophilia.

OBJECTIVE: To compare the safety, feasibility, and neuromuscular activity of acute low-load resistance exercise with/without blood flow restriction (BFR) in people with severe hemophilia (PwH). METHODS: Eight PwH under prophylaxis (5 with resistance training experience) performed 6 randomly ordered conditions of 3 intensity-matched knee extensions: no external load and no BFR, no external load and light BFR (20% of arterial occlusion pressure [AOP]), no external load and moderate BFR (40% AOP), external low load and no BFR, external low load with light BFR, and external low load with moderate BFR. Rated perceived exertion, pain, exercise tolerability, and adverse effects were assessed. Normalized root-mean-square (nRMS), nRMS spatial distribution, and muscle fiber-conduction velocity (MFCV) were determined using high-density surface electromyography for the vastus medialis and lateralis. RESULTS: Exercises were tolerated, without pain increases or adverse events. Externally resisted conditions with/without BFR provided greater nRMS than nonexternally resisted conditions (p < 0.05). Spatial distribution and MFCV did not vary between conditions. CONCLUSIONS: In these patients, knee extensions with low external resistance and BFR at 20% or 40% AOP appear safe, feasible and do not cause acute/delayed pain. However, BFR during three consecutive repetitions does not increase nRMS nor changes nRMS spatial distribution or MFCV.