Blood Flow Restriction Exercise Research Articles

Impact of limb occlusion pressure assessment position on performance, cardiovascular, and perceptual responses in blood flow restricted low-load resistance exercise: A randomized crossover trial

ABSTRACT This study investigated the effect of limb occlusion pressure (LOP) position on exercise performance, cardiovascular responses, and perceptual experiences during seated bilateral leg extensions with and without blood flow restriction (BFR). Thirty resistance-trained males (age: 22 ± 2 years; weight: 74.4 ± 13.6 kg; height: 177.4 ± 6.4 cm; BMI: 23.5 ± 3.3 kg/m2) participated. Each performed exercise to failure (4 sets, 30% 1RM, 1 min rest) in three conditions: Supine LOP-BFR, Seated LOP-BFR, and no-BFR. BFR was applied at 60% LOP. Significant interaction effects were found for RPE (p = 0.021, d = 0.76), RPD (p < 0.01, d = 1.72), and DOMS (p < 0.01, d = 2.28). Statistically significant fewer repetitions were completed in Supine LOP-BFR vs. no-BFR (p < 0.01, d = 0.5), Seated LOP-BFR vs. no-BFR (p < 0.01, d = 1.0), and Seated LOP-BFR vs. Supine LOP-BFR (p < 0.01, d = 0.6). RPE was higher in Seated LOP-BFR vs. no-BFR (p < 0.01, d = 0.52). RPD was higher in Supine LOP-BFR vs. no-BFR (p < 0.01, d = 0.62) and Seated LOP-BFR vs. no-BFR (p < 0.01, d = 1.25). DOMS was higher in Supine LOP-BFR vs. no-BFR (p < 0.01, d = 0.77) and Seated LOP-BFR vs. no-BFR (p < 0.01, d = 3.52). Seated LOP-BFR increased perceptual demands and reduced repetitions compared to Supine LOP-BFR. Both LOP-BFR conditions reduced repetitions compared to no-BFR without affecting cardiovascular measures.

The Effect of Blood Flow Restriction Exercise Prior to Total Knee Arthroplasty on Postoperative Physical Function, Lower Limb Strength and Patient-Reported Outcomes: ARandomized Controlled Trial.

30-s sit to stand (30STS). Timed Up&Go, 40-m walk test (40mWT), knee range of motion (ROM) 1-repetition maximum (1RM) leg press and knee extensor strength, maximal isometric contraction (MVIC) for the knee extensors and flexors, Knee injury and Osteoarthritis Outcome Score (KOOS), and Euroqol 5-dimensions (EQ-5D-L5) questionnaire. Data were collected at baseline (12 weeks pre-surgery), ~3 days pre-surgery, 3 and 12 months postoperatively. Intention-to-treat analysis revealed no significant between-group differences in the change from baseline to 3 and 12 months postoperatively on 30STS, TUG, or 40mFWT. Significant between-group differences were observed at 3 but not 12 months postoperatively for the corresponding changes in 1RM leg press strength, 1RM knee extensor strength, and MVIC knee extensor favoring BFR-RT. No between-group differences were observed for the delta changes from baseline in knee ROM, KOOS subscales or EQ-5D-L5 at any postoperative time points. These findings suggest that preoperative BFR-RT offered no superior effects compared with usual preoperative care on postoperative physical function or patient-reported outcomes. Preoperative BFR-RT produced amplified gains in lower limb muscle strength at 3 months postoperatively. NCT04081493.

Acute impact of autoregulation of applied blood flow restriction pressures on bilateral single-joint upper limb resistance exercise

ABSTRACT To investigate the acute effects of 4 sets of autoregulated (AR-BFR) versus non-autoregulated (NAR-BFR) applied pressures during blood flow restriction (BFR) resistance exercise to volitional failure compared with low-load exercise without BFR. A randomized crossover design study was conducted on 32 healthy adults (20.8 ± 2.3 years; 11 females). Outcome measures were as follows: (1) arterial stiffness, (2) peak perceptual responses and likelihood to perform again, and (3) performance. Results: Post-exercise changes in central and brachial diastolic blood pressure were decreased in all groups. Post-exercise supine systolic blood pressure in no-BFR increased (mean difference (MD) = 4 ± 1 mmHg, 95% CI (1–7), p = 0.003, η2 = 0.13). Total repetitions performed and volume workload were similar between BFR conditions but less than no-BFR. AR-BFR reported significantly higher exertion (MD = 0.53 ± 0.2, 95% CI (0.04–1.0), p = 0.03, η2 = 0.19) than other conditions, and induced greater discomfort (MD = 2.50 ± 0.36, 95% CI (1.63–3.37), p < 0.001, η2 = 0.28) than no-BFR. Conclusion: Biceps curl exercise to volitional failure appears to induce negligible arterial stiffness or blood pressure changes regardless of the application of autoregulation, yet autoregulation appears to enhance the perceptual response to BFR exercise compared to NAR-BFR without impacting exercise performance.

Effect of Aerobic Exercise with Blood Flow Restriction on Postexercise Hypotension in Young Adults: The Role of Histamine Receptors.

We tested hypothesis that aerobic exercise with blood flow restriction (BFR) induced postexercise hypotension (PEH), and the reduction in blood pressure (BP) was due to peripheral vasodilation via the histamine receptors. Ten male subjects participated in this study. The subjects were randomly assigned to walk for 10 min at 6.4 km/h, 0% grade with or without BFR after taking histamine receptor blockade. Following exercise, BP was measured at 10 min interval for 60 min. Heart rate (HR), stroke volume (SV), cardiac output (CO), mean arterial pressure (MAP), and total peripheral resistance (TPR) were evaluated. Our results indicated that MAP was significantly lowered immediately after exercise at 20 min, 30 min, and 40 min before the blockade as opposed to after the blockade. A significant reduction in diastolic BP (DBP) occurred. There were no significant differences in HR, SV, CO, and TPR between before the blockade and after the blockade. MAP was substantially decreased at 20 min, 30 min, and 40 min before the blockade compared to resting (-3.2 ± 2.2, -3.3 ± 2.8, and -2.9 ± 2.5, respectively) while increasing MAP after the blockade. The current study demonstrated that low-intensity aerobic exercise with BFR lowered MAP via histamine receptor-induced peripheral vasodilation. In conclusion, BFR exercise training using short periods and low intensity would be greatly beneficial as a potential treatment to lower BP.

Feasibility and safety of two weeks of blood flow restriction exercise in individuals with spinal cord injury

Context Reduced muscle strength and function are common after spinal cord injury (SCI). While low-load blood flow restriction exercise (BFRE) enhances muscle strength in healthy and clinical populations, its safety and feasibility in individuals with SCI remain underexplored. Objectives To investigate the feasibility and safety of low-load BFRE in individuals with incomplete SCI. Study Design Case series. Setting SCI rehabilitation center. Participants Six participants with motor incomplete SCI were enrolled in the study. Intervention A two-week BFRE intervention for the lower limbs was conducted twice weekly at 40% total arterial occlusion pressure, using 30-40% of 1-repetition maximum loads. Outcome Measures Feasibility measures, specifically recruitment and eligibility rates and intervention acceptability, were collected. Blood pressure (BP) responses and specific coagulation markers for deep vein thrombosis (DVT) were assessed as safety measures. Results Recruitment and eligibility rates were 2.8% and 6.6% for individuals admitted for first-time rehabilitation (subacute SCI) and 8.3% and 13.9% for 4-week readmission rehabilitation stays (chronic SCI), respectively. Intervention acceptability was high, characterized by 95.8% training adherence and low-to-moderate self-reported pain levels. BP responses and changes in C-reactive protein, Fibrinogen, and D-dimer during the intervention remained within clinically acceptable levels. Conclusion BFRE was feasible in an SCI rehabilitation setting despite a low recruitment rate. BFRE imposed no heightened risk of DVT or severe BP fluctuations in the present case series. Additionally, no severe adverse events occurred, and only mild complaints were reported. More extensive safety considerations warrant larger-scale exploration. Trial registration ClinicalTrials.gov identifier: NCT03690700.

Usability Of A Web-based Application For The Clinical Implementation Of Blood Flow Restriction Exercise

Usability Of A Web-based Application For The Clinical Implementation Of Blood Flow Restriction Exercise

Low-intensity blood flow restriction (LI-BFR) and moderate-intensity improves quadriceps strength and thigh circumference in older women

Background and objectives. Weakness and atrophy in the quadriceps femoris lead to decreased functional capacity, heightened fall risk, and increased mortality among older women. While moderate-intensity strength training is generally recommended for the elderly, higher-intensity exercises carry a greater risk of injury. Low-intensity exercises with blood flow restriction offer an alternative, providing comparable benefits to high-intensity training. This study aims to evaluate the effects of moderate-intensity and low-intensity blood flow restriction exercises on quadriceps femoris strength and thigh circumference in healthy elderly women. Materials and methods. The sample size was of 88 subjects equally randomized into a moderate-intensity group and a blood-flow restriction group. The moderate-intensity group performed strengthening exercises with a load of ≥40–60% of 1RM, 3 sets, 36 repetitions. The blood-flow restriction group conducted exercises at 20–30% of 1RM, completing 75 repetitions across 4 sets, using a pressure cuff applied to the upper thigh at 50 mmHg or 40% of the Arterial Occlusion Pressure (AOP). Both groups exercised twice a week over a 6-week period. Muscle strength (assessed via dynamometer and 1RM) and thigh circumference were recorded before and after the intervention. Results. After six weeks of intervention, both groups showed a significant increase in muscle strength and thigh circumference (p &lt;0.001). However, no notable differences were observed between the moderate intensity group and the blood flow restriction group regarding quadriceps strength (dynamometer), quadriceps 1RM strength, or thigh circumference (p &gt;0.05). Muscle soreness was reported in 18% of participants in the moderate intensity group. Conclusion. Low-intensity resistance exercises with blood flow restriction in older women can promote strength gains and muscle hypertrophy comparable to moderate-intensity training, while offering a safer alternative.

Enhancing upper extremity muscle strength in individuals with spinal cord injury using low-intensity blood flow restriction exercise.

This study explores the feasibility and effects of low-intensity blood flow restriction exercise on forearm muscle strength and function in individuals with spinal cord injury. Pilot randomized clinical trial. Ten male and female adult participants with chronic cervical and thoracic spinal cord injury underwent an 8-week low-intensity blood flow restriction exercise programme that targeted forearm muscles. Each participant's contralateral forearm served as the control. Grip strength was the primary outcome measure, and participants also provided qualitative feedback on their experiences. The study revealed a significant increase in participants' forearm muscle strength on the experimental side engaged in low-intensity blood flow restriction training, with an average strength gain of 7.5 ± 0.36 kg after 16 exercise sessions (Cohen's d = -6.32, 95% CI -8.34, -6.68). In comparison, the control side, following a conventional high- intensity exercise regimen without BFR, showed a more modest strength increase of 4.4 ± 0.67 kg. A mean Patient's Global Impression of Change score of 2.2 reflected overall improvements in participants' daily activities and health status. This study highlights the feasibility and effectiveness of low-intensity blood flow restriction exercise as a safe and promising approach to enhancing forearm muscle strength in individuals with spinal cord injury. The observed positive outcomes, coupled with a high level of participant satisfaction, underscore the potential of this innovative method to significantly improve limb muscle strength, thereby contributing to greater functional independence in this population.

The Effect of Low-Intensity Interval Exercise with Blood Flow Restriction on Plasma Cardiac Troponin: A Cross-Design Trial.

Low-intensity training with blood flow restriction (BFR) training could induce endurance adaptations, its impact on myocardial markers is still unclear compared to training without BFR. Consequently, the influence of low-intensity interval exercise with and without BFR and high-intensity interval exercise (HIIE) on cardiac troponin was determined in this study. Twelve physically active males between 18 and 26 years volunteered as participants. The participants completed 3 exercise tests in random order, which included 40% VO2max low-intensity cycling without BFR (group L), 40% VO2max low-intensity cycling with BFR set at 60% limb occlusion pressure (LOP) (group B), and 80% VO2max high-intensity cycling without BFR (group H). Participant muscle oxygen, blood flow, oxygen uptake, heart rate (HR), perceived exertion (RPE) rating, and pain levels were determined before and after exercise, after cuff inflation, and pre- and post-each exercise. Moreover, before each protocol, immediately after the exercises, and 3-4 hours after each exercise, elbow vein blood samples were collected to evaluate lactate (LA) and high-sensitivity cardiac troponin T (cTnT). Increased LA was recorded after exercise by the individuals in group H, which was more significant than in group B. Moreover, group B documented a more significant LA increment than group L (P < .05). The peak cTnT of groups B and H after exercise was significantly higher (P < .05). Furthermore, the increase was more significant than the values recorded by group L (P < .05). The present study demonstrated that low-intensity interval exercise combined with BFR could cause cTnT elevations compared to training without BFR. The increase was similar to HIIE protocols.

Implementation and Clinical Outcomes of Blood Flow Restriction Training on Adults With Cerebral Palsy: A Case Series.

Cerebral palsy (CP) is a congenital neurological disorder that causes musculoskeletal weakness and biomechanical dysfunctions. Strength training guidelines recommend at least 70% of 1-repetition maximum to increase muscle strength and mass. However, individuals with CP may not tolerate such high exercise intensity. Blood flow restriction (BFR) can induce similar gains in strength and muscle mass using loads as low as 20% to 30% 1-repetition maximum. This case series described the safety, feasibility, and acceptability of BFR in adults with CP and examined changes in muscle mass and strength. Three male participants with gross motor function classification system level 3 CP underwent strength training using a periodized 8-week BFR protocol. Outcomes included: Safety via blood pressure during and post-BFR exercises in addition to adverse event tracking; Feasibility via number of support people and time-duration of BFR exercises; Acceptability via rate of perceived discomfort (0-10) and qualitative interviews; Muscle Mass via ultrasonographic cross-sectional area of the quadriceps and hamstring; and Strength via (1) 3-repetition maximum in the leg press and knee extension, (2) isometric knee flexor and extensor muscle force measured with a hand-held dynamometer, and (3) 30-second sit-to-stand test. Participants replaced 2 exercises from their current regimen with seated knee extension and leg press exercises using progressively higher limb occlusion pressure and exercise intensity. Limb occlusion pressure started at 60%, by week 4 progressed to 80%, and then remained constant. The exercise repetition scheme progressed from fixed nonfailure repetition sets to failure-based repetition sets. Blood pressure never exceeded safety threshold, and no adverse events were reported. The BFR training was time-consuming and resource-intensive, but well-tolerated by participants (rate of perceived discomfort with a mean value of 5.8, 100% protocol adherence). Strength, as measured by 3-repetition maximum testing and 30-second sit-to-stand test, increased, but isometric muscle force and muscle mass changes were inconsistent. Blood flow restriction may be an effective means to increase strength in adults with CP who cannot tolerate high-intensity resistance training. Future research should compare BFR to traditional strength training and investigate mediators of strength changes in this population. for more insights from the authors (see the Video, Supplemental Digital Content available at: http://links.lww.com/JNPT/A473 ).

The effectiveness of low-load Blood flow restriction Exercise in patients with an acute Achilles tendon rupture treated Non-surgically (BEAN): Protocol for a randomized controlled trial

BackgroundBlood flow restriction exercise (BFRE) has been proposed as a viable method for preserving muscle mass and function after an injury during periods of load restrictions such as after an acute Achilles tendon rupture. However, its effectiveness and safety in patients with an Achilles tendon rupture have yet to be evaluated in a randomized trial. ObjectivesFirst, to investigate the effectiveness of early initiated BFRE in patients with non-surgically treated acute Achilles tendon rupture. Second, to evaluate whether it is better to apply BFRE in the beginning (1–12 weeks) or later (13–24 weeks) in the rehabilitation period. MethodsThis is an assessor-blinded, randomized, controlled multicenter trial with patients assigned in a 1:1 ratio to two parallel groups, that either receive BFRE in weeks 1–12 followed by usual care in weeks 13–24, or receive usual care in weeks 1–12 followed by BFRE in weeks 13–24. The BFRE program is performed three times weekly on the injured leg at 80 % of the pressure required to fully restrict the arterial blood flow. Post-intervention tests are conducted in week 13, comparing early BFRE with usual care, and in week 25, comparing early BFRE with late BFRE. At the 13-week evaluation, the primary outcome is the Single-Leg Heel-Rise test which assesses the patient’s ability to raise the heel of the injured leg a minimum of 2 cm. At the 25-week evaluation, the primary outcome is the Achilles tendon Total Rupture Score which assesses the patient’s self-reported symptoms and physical ability.

Application of Blood Flow Restriction Exercise in Knee Patients: Current Concepts Review

Application of Blood Flow Restriction Exercise in Knee Patients: Current Concepts Review

The Effects of Blood Flow Restriction Aerobic Exercise on Body Composition, Muscle Strength, Blood Biomarkers, and Cardiovascular Function: A Narrative Review.

Blood flow restriction exercise has emerged as a promising alternative, particularly for elderly individuals and those unable to participate in high-intensity exercise. However, existing research has predominantly focused on blood flow restriction resistance exercise. There remains a notable gap in understanding the comprehensive effects of blood flow restriction aerobic exercise (BFRAE) on body composition, lipid profiles, glycemic metabolism, and cardiovascular function. This review aims to explore the physiological effects induced by chronic BFRAE. Chronic BFRAE has been shown to decrease fat mass, increase muscle mass, and enhance muscular strength, potentially benefiting lipid profiles, glycemic metabolism, and overall function. Thus, the BFRAE offers additional benefits beyond traditional aerobic exercise effects. Notably, the BFRAE approach may be particularly suitable for individuals with low fitness levels, those prone to injury, the elderly, obese individuals, and those with metabolic disorders.

Blood Flow Restricted Resistance Exercise in Well-Trained Men: Salivary Biomarker Responses and Oxygen Saturation Kinetics

Blood Flow Restricted Resistance Exercise in Well-Trained Men: Salivary Biomarker Responses and Oxygen Saturation Kinetics

Low-Load Resistance Exercise With Blood Flow Restriction Versus High-Load Resistance Exercise on Hamstring Muscle Adaptations in Recreationally Trained Men.

Kamiş, O, Gürses, VV, Şendur, HN, Altunsoy, M, Pekel, HA, Yıldırım, E, and Aydos, L. Low-load resistance exercise with blood flow restriction vs. high-load resistance exercise on hamstring muscle adaptations in recreationally trained men. J Strength Cond Res XX(X): 000-000, 2024-Low-load resistance exercise with blood flow restriction (BFR-RE) has been suggested as a viable alternative exercise for traditional high-load resistance exercise (HL-RE). However, very little is known about hamstring muscle thickness, stiffness, and strength after BFR-RE. This study aimed to compare the effects of 6 weeks of BFR-RE and HL-RE on hamstring muscle thickness, stiffness, and strength. Twenty-nine recreationally trained men were pair matched and randomly assigned to the BFR-RE (n = 15) and HL-RE (n = 14) groups. The BFR-RE groups performed bilateral lying leg curl exercise (30-15-15-15 reps, 30-second rest between the sets, 30% 1RM) with BFR cuffs (60% of limb occlusion pressure), whereas HL-RE performed the same exercise (3 × 12 reps, 90-second rest between the sets, 70% 1RM) without BFR cuffs. Hamstring muscle thickness, muscle stiffness, isokinetic muscle strength, and 1RM were assessed at baseline and follow-up after completing a 6-week resistance exercise program (3× a week). Hamstring muscle thickness was assessed by ultrasonography, whereas muscle stiffness was evaluated by shear wave elastography. Isokinetic dynamometry and a 1RM strength test were used to determine muscular strength before and after the exercise program. Statistical significance was set at p < 0.05. No significant effect was found for hamstring muscle strength, thickness, and stiffness for group and group × time interaction, and only a significant main effect of time (p < 0.001) was observed for all outcomes. Both groups experienced significant improvements for all outcomes from baseline to follow-up without any between-group differences. In conclusion, results revealed that BFR-RE can provide similar hamstring muscle strength, thickness, and stiffness compared with HL-RE.

Comparing adaptations from blood flow restriction exercise training using regulated or unregulated pressure systems: A systematic review and meta-analysis

Objective No study has examined outcomes derived from blood flow restriction exercise training interventions using regulated compared with unregulated blood flow restriction pressure systems. Therefore, we used a systematic review and meta-analyses to compare the chronic adaptations to blood flow restriction exercise training achieved with regulated and unregulated blood flow restriction pressure systems. Data sources The electronic database search included using the tool EBSCOhost and other online database search engines. The search included Medline, SPORTDiscus, CINAHL, Embase and SpringerLink. Methods Included studies utilised chronic blood flow restriction exercise training interventions greater than two weeks duration, where blood flow restriction was applied using a regulated or unregulated blood flow restriction pressure system, and where outcome measures such as muscle strength, muscle size or physical function were measured both pre- and post-training. Studies included in the meta-analyses used an equivalent non-blood flow restriction exercise comparison group. Results Eighty-one studies were included in the systematic review. Data showed that regulated (n = 47) and unregulated (n = 34) blood flow restriction pressure systems yield similar training adaptations for all outcome measures post-intervention. For muscle strength and muscle size, this was reaffirmed in the included meta-analyses. Conclusion This review indicates that practitioners may achieve comparable training adaptations with blood flow restriction exercise training using either regulated or unregulated blood flow restriction pressure systems. Therefore, additional factors such as device quality, participant comfort and safety, cost and convenience are important factors to consider when deciding on appropriate equipment to use when prescribing blood flow restriction exercise training.

Acute neuromuscular and perceptual responses to blood flow restriction exercise in adults with severe haemophilia: A pilot study.

No previous studies have implemented a standard blood flow restriction (BFR) training session in people with severe haemophilia (PwH), where this type of training has been contraindicated. The purpose of this study was to evaluate the tolerability, adverse events, and neuromuscular and perceptual responses to an acute session of low load (LL) knee extensions with BFR in PwH under prophylaxis. Eight PwH performed one LL-BFR session with 40% arterial occlusion pressure (AOP). Perceptual responses and adverse effects were assessed, together with high-density surface electromyography of vastus medialis (VM) and lateralis (VL). Significant normalized root mean square differences were found within each set, but not between sets. Spatial distribution (centroid displacement (p>.05), modified entropy (VM, set two, cycles three and five, p=.032) and coefficient of variation (VM, set two, cycles four and five lower than cycle three (p=.049; p=.036)) showed changes within each set. Median frequency showed a slight increase during cycle four of set four (p=.030). Rate of perceived exertion slightly increased with each set while tolerability slightly decreased in the last set and fear of training with BFR generally decreased after the session. In PwH, a LL-BFR session at 40% AOP is safe and feasible. Our results suggest that potential muscle impairments may blunt neuromuscular adaptations induced by BFR.

Acute effects of blood flow restricted aerobic exercise in type 2 diabetes mellitus.

This study aimed to compare the acute effects of aerobic exercise performed with blood flow restriction (BFR), a novel method to increase exercise gains, with blood free flow (BFF) conditions in type 2 diabetes mellitus (T2DM). Fifteen individuals with T2DM performed BFF and BFR (40% of arterial occlusion pressure) cycling exercises 48 hours apart, at equal intensity (45% heart rate reserve) and duration (38 minutes). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), blood glucose, heart rate, and muscle oxygen saturation (SmO2) were assessed before-after and during exercise sessions. SBP, DBP, and MAP in the overload phase were higher in the BFR group than in the BFF group (P = .009, 0.031, and 0.013, respectively). Changes in blood pressure (∆SBP and ∆DBP) were similar between the BFF and BFR groups (P > .05), whereas ∆MAP differed (P = .016). Changes in blood glucose levels and heart rates were not significantly different between the groups. Although SmO2baseline was lower in the BFR group (P = .049), SmO2min and SmO2max did not differ significantly between the BFF and BFR groups. The similar decrease in blood glucose levels between the groups suggests that BFR exercise is favorable in terms of hypoglycemia. The higher blood pressure observed during the BFR exercise remained within safe limits. These results suggest that people with T2DM can safely perform BFR aerobic exercises; however, further studies are required.

Differential training benefits and motor unit remodeling in wrist force precision tasks following high and low load blood flow restriction exercises under volume-matched conditions

BackgroundBlood flow restriction (BFR) resistance training has demonstrated efficacy in promoting strength gains beneficial for rehabilitation. Yet, the distinct functional advantages of BFR strength training using high-load and low-load protocols remain unclear. This study explored the behavioral and neurophysiological mechanisms that explain the differing effects after volume-matched high-load and low-load BFR training.MethodsTwenty-eight healthy participants were randomly assigned to the high-load blood flow restriction (BFR-HL, n = 14) and low-load blood flow restriction (BFR-LL, n = 14) groups. They underwent 3 weeks of BFR training for isometric wrist extension at intensities of 25% or 75% of maximal voluntary contraction (MVC) with matched training volume. Pre- and post-tests included MVC and trapezoidal force-tracking tests (0–75%–0% MVC) with multi-channel surface electromyography (EMG) from the extensor digitorum.ResultsThe BFR-HL group exhibited a greater strength gain than that of the BFR-LL group after training (BFR_HL: 26.96 ± 16.33% vs. BFR_LL: 11.16 ± 15.34%)(p = 0.020). However, only the BFR-LL group showed improvement in force steadiness for tracking performance in the post-test (p = 0.004), indicated by a smaller normalized change in force fluctuations compared to the BFR-HL group (p = 0.048). After training, the BFR-HL group activated motor units (MUs) with higher recruitment thresholds (p < 0.001) and longer inter-spike intervals (p = 0.002), contrary to the BFR-LL group, who activated MUs with lower recruitment thresholds (p < 0.001) and shorter inter-spike intervals (p < 0.001) during force-tracking. The discharge variability (p < 0.003) and common drive index (p < 0.002) of MUs were consistently reduced with training for the two groups.ConclusionsBFR-HL training led to greater strength gains, while BFR-LL training better improved force precision control due to activation of MUs with lower recruitment thresholds and higher discharge rates.

Blood Flow Restriction Exercise as a Novel Conservative Standard in Patients with Knee Osteoarthritis—A Narrative Review

Knee osteoarthritis is a prevalent joint disease affecting millions of individuals globally. While total knee arthroplasty is an effective treatment for advanced stages of KOA, it may not be suitable for earlier stages or younger patients. Supervised exercise therapy has proven to be the first-line treatment of preference in tackling pain and disability caused by KOA. However, the high intensities required to induce positive muscle adaptations are not indicated in this population, as this is often accompanied by pain, discomfort, and frustration, leaving low-load resistance training as the only feasible method of treatment. Recently, the use of blood flow restriction training has begun to emerge as a substitute for high-load resistance training. With BFRT, a cuff is applied around the proximal aspect of the affected limb, causing partial arterial and full venous occlusion, thereby inducing localized hypoxia and the accumulation of metabolites, mimicking the effects of high-load resistance training, albeit with low loads. Consequently, BFRT might offer a suitable and more effective alternative for KOA patients who are not (yet) eligible for TKA compared to traditional exercise therapy. This review aims to summarize the current evidence as regards the application of Blood Flow Restriction in exercise therapy for knee osteoarthritis patients, with particular consideration of the underlying mechanisms and its safety, as well as general guidelines for practical implementation in clinical practice. In doing so, this narrative review aims to create a framework for translating from theory into practice.