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Background: Lower extremity bone stress injuries (BSI) are common injuries among athletes and military members. Typical management involves a period of restricted weightbearing which can have rapid detrimental effects upon both muscle and bone physiology. Few studies have investigated the effect of blood flow restriction (BFR) training on bone in the rehabilitative setting. Purpose: The purpose of this study was to investigate the effects of lower extremity exercise with the addition of BFR upon bone mineral density, bone mineral content, and lean body mass in military members with tibial BSIs. Study Design: Case series. Methods: Twenty military members with MRI-confirmed tibial BSI were recruited to complete lower extremity exercise with the addition of BFR twice per week for four weeks. The BFR cuff was applied proximally to the participant's involved limb while they performed gluteal, thigh, and leg resistance exercises. Outcomes were assessed at baseline and four weeks. The primary outcomes were whole leg bone mineral density (BMD), bone mineral content (BMC), and lean body mass (LM) as measured by dual-energy x-ray absorptiometry. Secondary outcomes included thigh and leg circumference measures and patient-reported outcomes, including the Lower Extremity Functional Scale (LEFS), Patient-Reported Outcomes Measurement Information System 57 (PROMIS-57), and Global Rating of Change (GROC). Results: No significant differences were found in BMD (p=0.720) or BMC (p=0.749) between limbs or within limbs over time. LM was generally less in the involved limb (p=0.019), however there were no significant differences between or within limbs over time (p=0.404). For thigh circumference, significant main effects were found for time (p=0.012) and limb (p=0.015), however there was no significant interaction effect (p=0.510). No significant differences were found for leg circumference (p=0.738). Participants showed significant mean changes in LEFS (15.15 points), PROMIS physical function (8.98 points), PROMIS social participation (7.60 points), PROMIS anxiety (3.26 points), and PROMIS pain interference (8.39 points) at four weeks. Conclusion: The utilization of BFR in the early rehabilitative management of tibial BSI may help mitigate decrements in both bone and muscle tissue during periods of decreased physical loading. Level of Evidence: 4.

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Purpose: The aim was to investigate the immediate effects of high-intensity resistance training with blood flow restriction (HIRT-BFR) on rectus femoris (RF) muscle activity, reaction time, muscular performance, and delayed onset muscle soreness (DOMS) in healthy young adults. Methods: Twenty-four healthy young adults were randomized into the HIRT-BFR group or HIRT group. Both groups performed a single session of training with 80% of 1RM, 8 repetitions, 2 sets, and 3 minutes rest to RF muscle. The activity and reaction time of the dominant extremity RF muscle were evaluated by superficial electromyography (sEMG), muscular performance by single-leg squat test, and DOMS by the Visual Analog Scale. Results: Single-leg squat performance was significantly increased in HIRT-BFR (p = .001) and HIRT group (p = .04). Additionally, in HIRT group resting average (p = .03), resting maximal voluntary contraction % (p = .04), and relaxation minimum (p = .02) values of RF were significantly increased. DOMS level decreased significantly in HIRT-BFR (p < .001) and HIRT group (p = .019). The differences were similar in the groups for sEMG parameters, muscle performance, and DOMS level. Conclusion: We observed that HIRT-BFR and HIRT were similar in terms of muscle activation, reaction time, muscular performance of the RF, and DOMS level.Trial registration number: This study is registered at www.clinicaltrails.gov (NCT05274542).

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Blood flow restriction pressures are set relative to the lowest pressure needed to occlude blood flow with that specific cuff. Due to pressure limitations of some devices, it is often not possible to occlude blood flow in all subjects and apply a known relative pressure in the lower body with a 5 cm wide cuff.Objective. To use a device capable of generating high pressures (up to 907 mmHg) to create and validate an estimation equation for the 5 cm cuff in the lower body using a 12 cm cuff.Approach. 170 participants had their arterial occlusion pressure (AOP) with a 5 cm and 12 cm cuff and their thigh circumference measured in their right leg. The sample was randomly allocated to a prediction group (66%) and validation group (33%). Thigh circumference and 12 cm AOP were used as predictors. A Bland-Altman plot was constructed to assess agreement between measured and predicted values.Main results. The mean difference (95% confidence interval) between the observed (336.8 mmHg) and the predicted (343.9 mmHg) 5 cm AOP was 7.1 (-11.9, 26.1) mmHg. The 95% limits of agreement were -133.6 to 147.8 mmHg. There was a negative relationship between the difference and the average of predicted and measured 5 cm AOP (B= -0.317,p= 0.000043).Significance. Although this was the first study to quantify AOP over 600 mmHg with a 5 cm cuff, our equation is not valid across all levels of pressure. If possible, larger cuff widths should be employed in the lower body.

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Resistance training (RT) with blood flow restriction (BFR) or high intensity (HI) are effective to increase muscle mass. To understand this effect, techniques known as "omics" are used to identify possible biomarkers. This study analyzed the salivary proteomic profile of healthy individuals trained before and after two RT protocols both designed with eight exercises for upper- and lower-limbs, one performed at low percentage of one-maximum repetition (%1RM) with BFR technique, and other at high %1RM (HI) without BRF technique. Four healthy males between 18 and 28 years participated in the study. Stimulated saliva was collected before (BBFR/BHI) and immediately after (ABFR/AHI) the two RT protocols. All protein-related processing was performed using label-free proteomic. The difference in expression between groups was expressed as p < .05 for downregulated proteins and 1-p > .95 for upregulated proteins. There was difference in salivary flow between ABFR and BBFR (p = .005). For HI, 87 proteins were found after the practice and 119 before. Three hemoglobin isoforms were increased in AHI compared with BHI. In the BFR comparison, 105 proteins were identified after (ABFR) and 70 before (BBFR). Among those increased ABFR, we highlight five hemoglobin isoforms and Deleted in malignant brain tumors 1 protein. Between ABFR and AHI, 17 isoforms of histones, Transaldolase, Transketolase, Glyceraldehyde-3-phosphate dehydrogenase, and Antileukoproteinase were decreased ABFR. For HI, there was an increase in proteins related to oxidative stress and metabolism of the musculoskeletal system, compared with BFR. HI seems to induce higher anabolic signaling to muscle mass increase and antiatherosclerotic effects.

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INTRODUCTION: Previous investigators have developed prediction equations to estimate arterial occlusion pressure (AOP) for blood flow restriction (BFR) exercise. Most equations have not been validated and are designed for use with expensive cuff systems. Thus, their implementation is limited for practitioners. PURPOSE: To develop and validate an equation to predict AOP in the lower limbs when applying an 18 cm wide thigh sphygmomanometer (SPHYG18cm). METHODS: Healthy adults (n = 143) underwent measures of thigh circumference (TC), skinfold thickness (ST), and estimated muscle cross-sectional area (CSA) along with brachial and femoral systolic (SBP) and diastolic (DBP) blood pressure. Lower-limb AOP was assessed in a seated position at the posterior tibial artery (Doppler ultrasound) using a SPHYG18cm. Hierarchical linear regression models were used to determine predictors of AOP. The best set of predictors was used to construct a prediction equation to estimate AOP. Performance of the equation was evaluated and internally validated using bootstrap resampling. RESULTS: Models containing measures of either TC or thigh composition (ST and CSA) paired with brachial blood pressures explained the most variability in AOP (54%) with brachial SBP accounting for majority of explained variability. A prediction equation including TC, brachial SBP, and age showed good predictability (R2 = 0.54, RMSE = 7.18 mmHg) and excellent calibration. Mean difference between observed and predicted values was 0.0 mmHg and 95% Limits of Agreement were ± 18.35 mmHg. Internal validation revealed small differences between apparent and optimism adjusted performance measures, suggesting good generalizability. CONCLUSION: This prediction equation for use with a SPHYG18cm provided a valid way to estimate lower-limb AOP without expensive equipment.

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The purpose of this systematic review and meta-analysis was to compare changes in explosive power between blood flow restriction training and traditional resistance training protocols. Searches of PubMed, Scopus, Web of Science, and OVID Medline were conducted for studies. Inclusion criteria were: (a) healthy people; (b) randomized controlled or controlled trials; (c) outcome measures of explosive performance (peak power, rate of force development, jump performance, sprint performance, etc.); (d) involving a comparison between blood flow restriction training and traditional resistance training. Quality assessment was conducted using the Physiotherapy Evidence Database (PEDro) scale. A total of 12 studies (262 subjects) were finally included for analysis. The PEDro scale score had a median of 5 of 10 points (range: 3-6 points). Significant small to moderate improvements were observed in blood flow restriction training [jump: standard mean difference (SMD) of 0.36 (95% CI: 0.02; 0.69); sprint: SMD of 0.54 (95% CI: 0.00; 1.07); power: SMD of 0.72 (95% CI: 0.17; 1.27)] when compared to traditional resistance training. The findings indicate that blood flow restriction training is more effective in improving explosive power of lower limbs compared to traditional resistance training in healthy people. In addition, blood flow restriction with a wide cuff (≥ 10 cm) during training improved explosive power better than with a narrow cuff or during the rest interval. Blood flow restriction training is very suitable for athletes in short competitive seasons and those who are not able to tolerate high loads (i.e., rehabilitators and the elderly).

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OBJECTIVE: To compare the effect of low-load blood flow restricted resistance training (BFR-RT) versus high-load resistance training (HL-RT) on muscle strength, muscle mass, physical function, patient-reported outcomes, and adherence to training in clinical musculoskeletal populations. DATA SOURCES: Web of Science, Cochrane Central, Medline, Embase, SportDiscus was searched on the 30th May 2022. REVIEW METHODS: This study was conducted as a systematic review and meta-analysis. Randomized Controlled Trials (RCTs) were included if they (i) included patients, (ii) comprised of a BFR-RT intervention protocol and a group who performed HL-RT (≥ 70%1RM) for at least eight exercise sessions, and (iii) involved at least 1 exercise that targeted the lower limbs. The Cochrane Risk of Bias tool was used to evaluate the risk of bias. The meta-analyses were performed using a random effects model with an adjustment to the confidence interval. RESULTS: Seven RCTs comprising 303 participants (BFR-RT: n = 151; HL-RT: n = 152) were identified. HL-RT and BFR-RT showed similar gains in dynamic (1-10RM) knee extensor strength and leg press strength, quadriceps cross sectional area, sit-to-stand performance, and patient reported pain and function. There was a moderate effect favoring BFR-RT for increasing maximal isometric knee extensor strength. The grading of certainty in evidence was low-to-very low for all outcome variables. CONCLUSION: This systematic review and meta-analysis extends our current knowledge about BFR-RT and HL-RT as equally effective exercise methods for inducing gains in maximal muscle strength in healthy populations, by now also comprising patients suffering from various clinical musculoskeletal conditions. The certainty in the estimates was low-to-very low, prompting the inclusion of future higher-quality trials. TRIAL REGISTRATION: PROSPERO ID (CRD42022337173). Registered June 18th 2022.

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Objective: Measurement of arterial occlusion pressure (AOP) is essential to the safe and effective use of blood flow restriction during exercise. Use of a Doppler ultrasound (US) is the "gold standard" method to measure AOP. Validation of a handheld Doppler (HHDOP) device to measure AOP could make the measurement of AOP more accessible to practitioners in the field. The purpose of this study was to determine the accuracy of AOP measurements of the brachial and femoral arteries using an HHDOP. Methods: We simultaneously measured AOP using a "gold standard" US and a HHDOP in the dominant and non-dominant arms (15 males; 15 females) and legs (15 males; 15 females). Results: There were no differences in limb circumference or limb volume in the dominant and non-dominant arms and legs between males and females or between the dominant and non-dominant arms and legs of males and females. The differences between US and HHDOP measures of AOP in the dominant and non-dominant arms and legs were either not significant or small (<10 mmHg) and of little practical importance. There were no sex differences in AOP measurements of the femoral artery (p > 0.60). Bland-Altman analysis yielded an average bias (-0.65 mmHg; -2.93 mmHg) and reasonable limits of agreement (±5.56 mmHg; ±5.58 mmHg) between US and HHDOP measures of brachial and femoral artery AOP, respectively. Conclusion: HHDOP yielded acceptable measures of AOP of the brachial and femoral arteries and can be used to measure AOP by practitioners for the safe and effective use of blood flow restriction. Due to the potential differences in AOP between dominant and non-dominant limbs, AOP should be measured in each limb.

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Accumulating evidence indicates that some COVID-19 survivors display reduced muscle mass, muscle strength, and aerobic capacity, which contribute to impairments in physical function that can persist for months after the acute phase of illness. Accordingly, strategies to restore muscle mass, muscle strength, and aerobic capacity following infection are critical to mitigate the long-term consequences of COVID-19. Blood flow restriction (BFR), which involves the application of mechanical compression to the limbs, presents a promising therapy that could be utilized throughout different phases of COVID-19 illness. Specifically, we hypothesize that: 1) use of passive BFR modalities can mitigate losses of muscle mass and muscle strength that occur during acute infection and 2) exercise with BFR can serve as an effective alternative to high-intensity exercise without BFR for regaining muscle mass, muscle strength, and aerobic capacity during convalescence. The various applications of BFR may also serve as a targeted therapy to address the underlying pathophysiology of COVID-19 and provide benefits to the musculoskeletal system as well as other organ systems affected by the disease. Consequently, we present a theoretical framework with which BFR could be implemented throughout the progression from acute illness to outpatient rehabilitation with the goal of improving short- and long-term outcomes in COVID-19 survivors. We envision that this paper will encourage discussion and consideration among researchers and clinicians of the potential therapeutic benefits of BFR to treat not only COVID-19 but similar pathologies and cases of acute critical illness.

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Introduction: The efficacy of low-intensity blood flow restriction (LI-BFR) training programs in bone metabolism remains unclear compared to low-intensity (LI) training and high-intensity (HI) training. The aim of this review was to quantitatively identify the effects of LI-BFR training on changes in bone formation markers (i.e., bone-specific alkaline phosphatase, BALP), bone resorption (i.e., C-terminal telopeptide of type I collagen, CTX) and bone mineral density (BMD) compared with conventional resistance training programmes. Additionally, the effectiveness of walking with and without BFR was assessed. Methods: PubMed, Scopus, SPORTDiscus, Web of Science and Google Scholar databases were searched for articles based on eligibility criteria. Review Manager Version 5.4 was used for Meta-analysis. Physiotherapy Evidence Database (PEDro) was applied to assess the methodological quality of studies. Results: 12 articles were included in the meta-analysis, with a total of 378 participants. Meta-results showed that compared with LI training, LI-BFR training induced greater increments in BALP (young adults: MD = 6.70, p < 0.001; old adults: MD = 3.94, p = 0.002), slight increments in BMD (young adults: MD = 0.05, p < 0.00001; old adults: MD = 0.01, p < 0.00001), and greater decrements in CTX (young adults: MD = -0.19, p = 0.15; old adults: MD = -0.07, p = 0.003). Compared with HI training, LI-BFR training produced smaller increments in BALP (young adults: MD = -6.87, p = 0.24; old adults: MD = -0.6, p = 0.58), similar increments in BMD (MD = -0.01, p = 0.76) and similar decrements in CTX (young adults: MD = 0, p = 0.96; old adults: MD = -0.08, p = 0.13). Although there were only two studies on walking training intervention, walking training with BFR had a better effect on bone metabolism than training without BFR. Discussion: In conclusion, LI-BFR training induces greater improvements in bone health than LI training, but is less effective than HI training. Therefore, LI-BFR training may be an effective and efficient way to improve bone health for untrained individuals, older adults, or those undergoing musculoskeletal rehabilitation. Clinical Trial Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42023411837].

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Low-load resistance training combined with blood flow restriction (BFR) is known to result in muscle hypertrophy and strength similar to that observed with higher loads. However, the effects of resistance training with BFR on cardiac structure and cardiac function remain largely unknown. Therefore, the purpose of this randomized study was to compare the effects of conventional high-load resistance training (HL-RT) with the effects of low-load resistance training with BFR (LL-BFR) on muscle strength and left ventricular function. Sixteen young swimmers (mean ± standard deviation: age = 19.7 ± 1.6 years, body mass = 78.9 ± 9.7 kg, body height = 180.8 ± 5.8 cm) were randomly allocated to a conventional HL-RT group (n = 8) or a LL-BFR group (n = 8) with a pressure band (200 mmHg) placed on both thighs of participants for 4 weeks (3 days•week-1). Outcome measures were taken at baseline and after 4 weeks of training, and included body composition, one-repetition maximum (1RM) back squat, and echocardiography measures. The 1RM back squat significantly improved (partial eta squared (È 2) = 0.365; p = 0.013) in HL-RT (mean difference (Δ) = 6.6 kg; [95% confidence interval (CI) -7.09 to 20.27]) and LL-BFR groups (Δ = 14.7 kg; [95% CI 3.39 to 26.10]), with no main effect of group or group × time interaction (p > 0.05). Interventricular septum end-systolic thickness showed a slight but statistically significant increase in LL-BFR and HL-RT groups (È 2 = 0.253; p = 0.047), yet there was no main effect of group or group × time interaction (p > 0.05). There were no statistically significant changes (p > 0.05) in other cardiac structure or function parameters (e.g., left ventricular (LV) mass, LV cardiac output, LV ejection fraction, LV stroke volume) after the training programs. Results suggest that 4 weeks of HL-RT and LL-BFR improve muscle strength similarly with limited effects on left ventricular function in young swimmers.

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BACKGROUND: Muscle atrophy, muscle weakness and localised pain are commonly reported following musculoskeletal injury (MSKI). To mitigate this risk and prepare individuals to return to sport or physically demanding occupations, resistance training (RT) is considered a vital component of rehabilitation. However, to elicit adaptations in muscle strength, exercise guidelines recommend lifting loads ≥ 70% of an individual's one repetition maximum (1-RM). Unfortunately, individuals with persistent knee pain are often unable to tolerate such high loads and this may negatively impact the duration and extent of their recovery. Low load blood flow restriction (LL-BFR) is an alternative RT technique that has demonstrated improvements in muscle strength, hypertrophy, and pain in the absence of high mechanical loading. However, the effectiveness of high-frequency LL-BFR in a residential rehabilitation environment remains unclear. This study will compare the efficacy of high frequency LL-BFR to 'conventional' heavier load resistance training (HL-RT) on measures of physical function and pain in adults with persistent knee pain. METHODS: This is a multicentre randomised controlled trial (RCT) of 150 UK service personnel (aged 18-55) admitted for a 3-week residential rehabilitation course with persistent knee pain. Participants will be randomised to receive: a) LL-BFR delivered twice daily at 20% 1-RM or b) HL-RT three-times per week at 70% 1-RM. Outcomes will be recorded at baseline (T1), course discharge (T2) and at three-months following course (T3). The primary outcome will be the lower extremity functional scale (LEFS) at T2. Secondary outcomes will include patient reported perceptions of pain, physical and occupational function and objective measures of muscle strength and neuromuscular performance. Additional biomechanical and physiological mechanisms underpinning both RT interventions will also be investigated as part of a nested mechanistic study. DISCUSSION: LL-BFR is a rehabilitation modality that has the potential to induce positive clinical adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits who are unable to tolerate heavy load RT. Consequently, results from this study will have a direct clinical application to healthcare service providers and patients involved in the rehabilitation of physically active adults suffering MSKI. TRIAL REGISTRATION: ClinicalTrials.org reference number, NCT05719922.

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BACKGROUND: To evaluate the effects of recumbent sprint interval exercise with and without blood flow restriction and body cooling on interference control and whether the changes in interference control can be explained by the changes in blood lactate. METHODS: 85 participants (22 SD 3 years old) completed 1 familiarization visit and then 5 experimental visits in a randomized order: exercise only (Ex), exercise with blood flow restriction (ExB), exercise with cooling (ExC), and exercise with blood flow restriction and cooling (ExBC), and non-exercise control (Con). Measurements of blood lactate and the Stroop Color Word Test were performed before and after exercise. Each bout began with a 15-minute low-moderate intensity warm-up, followed by five 20-second "all out" sprints separated by 40 s of active recovery. Bayes Factors (BF10) quantified evidence for or against the null hypothesis. Within-subject mediation analysis quantified the indirect effect of changes in blood lactate (mediator) on the change in interference control (each exercise condition vs. Con). RESULTS: Bayesian pairwise comparisons found that only ExC [σ: -0.37 (-0.59, -0.15)] and ExBC [σ: -0.3 (-0.53, -0.09)] produced changes in incongruent reaction time different from that of Con. There was also evidence that all exercise conditions increased blood lactate (BF10 = 8.65e+29 - 1.9e+32) and improved congruent reaction time (BF10 = 4.01 - 15.371) compared to that of Con. There was no evidence to show that changes in lactate mediated the change in incongruent reaction time. CONCLUSIONS: Both exercise with body cooling and when body cooling was combined with blood flow restriction presented favorable changes in incongruent reaction time (a marker of interference control), which might not be explained by the changes in systemic blood lactate concentration.

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Persistent dysphagia is a major predictor of prolonged ventilation weaning and unsuccessful attempts at decannulation. Due to the high incidence of dysphagia in tracheotomized patients, tracheal cannula management and dysphagia treatment must be coordinated. A central element of tracheal cannula management in dysphagia treatment is the establishment of physiological airflow. This enables voluntary clearing functions, such as coughing and throat clearing and significantly reduces aspiration. A distinction is made between spontaneous and staged decannulation pathways with expansion of cuff unblocking times and occlusion training. Other therapeutic measures include secretion and saliva management, cough function training with improvement of strength and sensitivity, pharyngeal electrical stimulation, adaptation of tracheal tubes to optimize respiratory and swallowing function, control and treatment of airway stenosis, and standardization of processes for quality assurance.

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Training with blood flow restriction (BFR) has been shown to be a useful technique to improve muscle hypertrophy, muscle strength and a host of other physiological benefits in both healthy and clinical populations using low intensities [20%-30% 1-repetition maximum (1RM) or <50% maximum oxygen uptake (VO2max)]. However, as BFR training is gaining popularity in both practice and research, there is a lack of awareness for potentially important design characteristics and features associated with BFR cuff application that may impact the acute and longitudinal responses to training as well as the safety profile of BFR exercise. While cuff width and cuff material have been somewhat addressed in the literature, other cuff design and features have received less attention. This manuscript highlights additional cuff design and features and hypothesizes on their potential to impact the response and safety profile of BFR. Features including the presence of autoregulation during exercise, the type of bladder system used, the shape of the cuff, the set pressure versus the interface pressure, and the bladder length will be addressed as these variables have the potential to alter the responses to BFR training. As more devices enter the marketplace for consumer purchase, investigations specifically looking at their impact is warranted. We propose numerous avenues for future research to help shape the practice of BFR that may ultimately enhance efficacy and safety using a variety of BFR technologies.

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Lateral elbow tendinopathy (LET) is a common overuse injury with complex underlying pathophysiological mechanisms. Although several modes of exercise with or without passive interventions have been recommended as the first-line treatment option of the condition, their effectiveness remains inconclusive. The aim of this case report is to evaluate the effect of wrist extensor exercises with blood flow restriction (BFR) as an add-on intervention to a multi-modal physiotherapy programme to improve outcomes in a patient with LET. A 51-year-old male patient presented with a history of right LET for six months. Interventions included wrist extension exercise with BFR, a two-stage progressive loading training programme of the upper limb, soft-tissue massage, education and a home exercise programme for six weeks (12 visits). A substantial improvement in pain intensity, pain-free grip strength, Patient Rated Tennis Elbow Evaluation score and self-perceived recovery was reported at three-, six-, and 12-week follow-up measurements. A 21% reduction in pressure pain thresholds at the lateral epicondyle was found immediately after wrist extensor exercise with BFR. Based on our findings, adding wrist extensor exercises with BFR to a multimodal physiotherapy programme seems a promising approach to improve the treatment outcome in LET. Nonetheless, further research is needed to confirm the present results.

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Low-intensity exercise with blood flow restriction (LIE-BFR) has been proposed as an effective intervention to induce hypoalgesia in both healthy individuals and patients with knee pain. Nevertheless, there is no systematic review reporting the effect of this method on pain threshold. We aimed to evaluate the following: (i) the effect of LIE-BFR on pain threshold compared to other interventions in patients or healthy individuals; and (ii) how different types of applications may influence hypoalgesic response. We included randomized controlled trials assessing the effectiveness of LIE-BFR alone or as an additive intervention compared with controls or other interventions. Pain threshold was the outcome measure. Methodological quality was assessed using the PEDro score. Six studies with 189 healthy adults were included. Five studies were rated with 'moderate' and 'high' methodological quality. Due to substantial clinical heterogeneity, quantitative synthesis could not be performed. All studies used pressure pain thresholds (PPTs) to assess pain sensitivity. LIE-BFR resulted in significant increases in PPTs compared to conventional exercise at local and remote sites 5 min post-intervention. Higher-pressure BFR results in greater exercise-induced hypoalgesia compared to lower pressure, while exercise to failure produces a similar reduction in pain sensitivity with or without BFR. Based on our findings, LIE-BFR can be an effective intervention to increase pain threshold; however, the effect depends on the exercise methodology. Further research is necessary to investigate the effectiveness of this method in reducing pain sensitivity in patients with pain symptomatology.

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This study examined the acute effects of high-intensity resistance exercise with blood flow restriction (BFR) on performance and fatigue, metabolic stress, and markers of inflammation (interleukin-6 (IL-6)), muscle damage (myoglobin), angiogenesis (vascular endothelial growth factor (VEGF)). Thirteen resistance-trained participants (four female, 24.8 ± 4.7 years) performed four sets of barbell back-squats (75% 1RM) to failure under two conditions: blood flow restriction (BFR, bilateral 80% occlusion pressure) and control (CTRL). Completed repetitions and pre-post-exercise changes in maximal voluntary isometric contractions, countermovement jump, barbell mean propulsive velocity, and surface electromyography were recorded. Pre-post blood lactate (BLa) and venous blood samples for analysis of IL-6, myoglobin, and VEGF were collected. Ratings of perceived exertion (RPE) and pain were recorded for each set. Fewer repetitions were performed during BFR (25.5 ± 9.6 reps) compared to CTRL (43.4 ± 14.2 reps, p < 0.001), with greater repetitions performed during sets 1, 2, and 4 (p < 0.05) in CTRL. Although RPE between conditions was similar across all sets (p > 0.05), pain was greater in BFR across all sets (p < 0.05). Post-exercise fatigue was comparable between conditions. BLa was significantly greater in CTRL compared to BFR at two minutes (p = 0.001) but not four minutes post-exercise (p = 0.063). IL-6 was significantly elevated following BFR (p = 0.011). Comparable increases in myoglobin (p > 0.05) and no changes in VEGF were observed (p > 0.05). BFR increases the rate of muscular fatigue during high-intensity resistance exercise and acutely enhances IL-6 response, with significantly less total work performed, but increases pain perception, limiting implementation.

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OBJECTIVES: Explore the feasibility of lower-limb garment-integrated BFR-training. DESIGN: Observational study. SETTING: Human performance laboratory. PARTICIPANTS: Healthy males with no experience of BFR-training. MAIN OUTCOME MEASURES: Feasibility was determined by a priori thresholds for recruitment, adherence, and data collection. Safety was determined by measuring BFR torniquet pressure and the incidence of side effects. Efficacy was determined by measuring body anthropometry and knee isokinetic dynamometry. Feasibility and safety outcomes were reported descriptively or as a proportion with 95% confidence intervals (95% CI), with mean change, 95% CIs, and effect sizes for efficacy outcomes. RESULTS: Twelve participants (mean age 24.8 years [6.5]) were successfully recruited; 11 completed the study. 134/136 sessions were completed (adherence = 98.5%) and 100% of data were collected. There was one event of excessive pain during exercise (0.7%, 95% CI 0.0%, 4.0%), two events of excessive pain post-exercise (1.5%, 95% CI 0.4%, 5.5%), and one event of persistent paraesthesia post-exercise (0.7%, 95% CI 0.0%, 4.0%). Mean maximal BFR torniquet pressure was <200 mmHg. We observed an increase in knee extension peak torque (mean change 12.4 Nm), but no notable changes in body anthropometry. CONCLUSIONS: Lower-limb garment-integrated BFR-training is feasible, has no signal of important harm, and could be used independently.

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