Nicholas Rolnick

Between the two pressure regulation settings, indicating that regulation of applied pressure may not be necessary to maximize physiological and neuromuscular responses during non-failure BFR resistance exercise. Akçay et al. (Akçay et al., 2026) performed the first longitudinal resistance-training trial that sought to determine whether there were any muscle hypertrophy and strength differences between regulated and unregulated pressures over 8 weeks in a withinsubject design using the Fitcuffs 4.0 BFR cuffs. Their findings extend on the acute findings of Moghaddam et al. to a chronic training context indicating that the autoregulatory feature of a BFR cuff may not provide additional benefit on muscle-related outcomes that justify its higher price point. These two studies provide practical takeaways for the BFR practitioner, offering initial insights into features that may not necessarily be required for optimizing acute or longitudinal responses to BFR exercise.The third theme within this special topic is showcasing BFR's broad efficacy across diverse populations, prescriptions, and exercise contexts. These papers highlight the real benefits of BFR against low-and high-load comparators but also illuminate that some of the uneven benefits observed may be due to methodological aspects of the BFR application and implementation parameters across different studies. For example, He et al. (He et al., 2025)'s review on BFR resistance training modalities in athletes outlines the mechanisms of BFR-induced adaptations as well as the common application schemes employed in the literature, providing a conceptual framework for classifying BFR training approaches in athletic contexts. Brown et al. (Brown et al., 2025) aimed to determine differences between continuous and intermittent BFR pressure applications in low-intensity aerobic exercise. Their findings show different acute cardiovascular, perceptual, and muscle oxygenation responses between pressure approaches, offering practical guidance on programming with BFR in populations with lower tolerances to occlusive-based exercise. Cerqueira et al. (Cerqueira et al., 2025) performed a pilot trial in knee osteoarthritis patients that compared occlusion pressure and blood pressure responses over 9 weeks between low-intensity (10% 1RM) and moderate-intensity (60% 1RM) exercise. They found no changes in blood pressure or occlusion pressure over the trial period, indicating the stability of both and supporting less frequent LOP assessments within this population, potentially reducing the burden of BFR's implementation over a training period by reducing the number of assessments performed. Xia et al. (Xia et al., 2026) performed a pilot study looking at whether a 4-week exercise program performed with BFR could positively affect task-related surface electromyography activation and functional performance transfer versus a control exercise. Their findings indicate a short-term BFR program may enhance neuromuscular efficiency before functional gains emerge, highlighting that the duration and outcomes selected for BFR exercise trials may significantly influence whether meaningful changes are observed or not. Wang et al. (Wang et al., 2026) compared 6 weeks of unilateral low-load BFR training against high-load non-BFR training using Bulgarian split-squats in resistance-trained men, looking to determine strength, hypertrophy, and performance-related outcomes in addition to cross-education. Their findings agree with the literature at large, further supporting low-load BFR as an alternative to high-load exercise, as no differences were observed in any outcome measures. Ahmad et al. (Ahmad et al., 2026) performed a single-blind, two-arm randomized 6-week training trial in inactive university-aged adults. Each group performed an identical low-load multi-component exercise program including sprints, jumps, squats, limb flexion and extension, pull-ups, curls, and grip work, increasing from 30% 1RM to 40% 1RM using 50% LOP. They found BFR produced significantly greater gains in most outcome measures (10 of 18), indicating the effectiveness of integrating BFR into low-load exercise paradigms. Qu et al. (Qu et al., 2026) looked at the impact of a low-load BFR resistance training program on lower-limb morphology and sport-relevant functional performance in male collegiate table tennis athletes. Their findings extend the evidence on BFR training to a trained, understudied athletic population, supporting its use during in-season training or supplemental conditioning where reduced joint loading or systemic stress is desired.The papers in this special topic continue to highlight the growth of BFR in exercise science, rehabilitation, and sports performance, and further examine how the method of application, assessment, and the technologies embedded within the cuff itself affect acute and long-term responses. As BFR research continues to grow, we call on researchers to pay close attention to how these methodological features may alter the BFR stimulus, and to adopt sound reporting practices for all trials (Hughes et al., 2025).

Objective. To evaluate the validity, reliability, agreement, and operational feasibility of an automated arterial occlusion pressure (AOP) assessment system compared with a manual Doppler-based assessment. Approach. Forty healthy adults (20 men and 20 women) completed upper- and lower-limb (LL) AOP assessments using automated and MDA methods in a randomized and counterbalanced design. Concurrent validity, agreement, intraday and interday reliability, operational feasibility, perceptual responses, and procedure-related symptoms were evaluated. Exploratory analyses examined whether sex modified the difference between automated and MDA-derived AOP measurements. Main results. MDA demonstrated good-to-excellent reliability (ICC = 0.84–0.98; CV = 1.38%–3.25%). The automated system demonstrated moderate-to-good intraday reliability (ICC = 0.74–0.85) but poor LL interday reliability (ICC = 0.36). Compared with MDA, automated AOP showed systematic bias and wide limits of agreement. No evidence of a sex-related difference in the between-method discrepancy was observed for either upper- or LL AOP. Although automated assessment reduced testing time by 81.9%–86.7%, frequent upper-limb (UL) measurement failures reduced the automated measurement success rate to approximately 57%, substantially increasing adjusted assessment time and limiting operational feasibility, while discomfort and affective responses were more favorable than with MDA. Significance. The automated AOP system improved assessment efficiency and participant experience but demonstrated less favorable reliability estimates, limited agreement, and frequent upper-limb measurement failures. Consequently, automated and MDA should not be considered interchangeable for individualized AOP prescription.

Objective . Accurate arterial occlusion pressure (AOP) measurement is essential for individualized blood flow restriction (BFR) prescription, but no automated BFR device has been validated across the range of body positions commonly used in practice. This study evaluated the validity, tolerability, and feasibility of automated algorithm-based AOP measurement compared to pulsed-wave Doppler ultrasound across supine, seated, and standing positions. Approach . Forty-six healthy adults completed AOP measurements on the dominant lower limb using both automated and Doppler ultrasound methods at three body positions in randomized order. Validity was assessed using intraclass correlation coefficients (ICC), Bland–Altman analysis, and proportional bias testing. Tolerability was evaluated through measurement duration, pain perception (0–10), and adverse event surveillance. Feasibility was assessed by the first-attempt success rate. Main results . The automated method demonstrated good agreement with Doppler ultrasound in supine (ICC = 0.76), seated (ICC = 0.87), and standing (ICC = 0.83) positions. However, 95% limits of agreement ranged from −38 to +48 mmHg across positions, and a significant negative proportional bias was observed in supine ( p = 0.031). Automated measurements required significantly longer duration than Doppler across all positions ( p < 0.001), while pain perception was comparable between methods. A single participant withdrew during standing automated measurement due to intolerable pain. The first-attempt success rate was significantly lower for automated measurement in standing compared to Doppler (87% vs 100%, p = 0.041) but comparable in supine and seated. Significance . The automated device demonstrates good validity and acceptable tolerability for AOP assessment in healthy young adults during seated and standing positions. Clinicians should consider manual ultrasound verification for supine measurements or when prescribing high-percentage AOP protocols, and provide postural support during standing measurements to improve first-attempt success.

Blood flow restriction exercise is increasingly used in rehabilitation and sport because it can improve muscular and cardiovascular outcomes at low intensities, yet optimal cuff-pressure prescription remains debated. This point–counterpoint article evaluates whether arterial occlusion pressure (AOP)–based prescription is necessary, practical, and important for research and clinical practice. The Point argues that AOP offers a physiologically grounded reference that reduces the risk of supra-occlusive pressures, improves reproducibility across individuals and devices, and supports safer use in clinical and at-risk populations. The Counterpoint contends that serious adverse events are rare across diverse prescription methods; that AOP varies with posture, time of day, and measurement technique; and that resting AOP may not reflect hemodynamic responses during exercise. It further argues that favorable adaptations occur across a wide range of pressures, making usability, tolerability, and adherence central to real-world effectiveness.

Objectives This systematic review and meta-analysis evaluated the efficacy of low-load exercise with blood flow restriction (LLE-BFR) compared with low-load exercise (LLE) and high-load exercise (HLE) in individuals with musculoskeletal (MSK) conditions on muscle strength, disability and pain intensity. Method Systematic review and meta-analysis of randomised clinical trials (RCTs). Methodological quality and risk of bias were assessed using the Physiotherapy Evidence Database (PEDro) scale and the Cochrane Risk of Bias 2 (RoB 2) tool. Data source Six databases were searched without language restrictions from inception to November 2025, with additional studies identified from reference lists. Eligibility criteria for selecting studies RCTs evaluating LLE-BFR versus LLE or HLE on muscle strength, pain intensity, disability and adverse events in people with MSK conditions. Results We included 45 RCTs (1652 participants), with 44 RCTs (1607 participants) contributing to meta-analyses (mean PEDro score=6.55; most of the included trials were rated as ‘some concerns’ across one or more RoB 2 domains). Low-certainty evidence indicated LLE-BFR was superior to LLE for muscle strength (standardised mean difference (SMD)=0.82, 95% CI 0.40 to 1.23) and disability (SMD=0.63, 95% CI 0.36 to 0.89). Moderate-certainty evidence showed no clear difference between LLE-BFR and HLE for muscle strength (SMD=0.08, 95% CI −0.20 to 0.35), and very-low certainty evidence showed no clear difference for disability (SMD=0.66, 95% CI −0.16 to 1.47). Moderate- and low-certainty evidence indicated small, unimportant differences favouring LLE-BFR over LLE (MD=4.45, 95% CI 1.21 to 7.71) and HLE (MD=7.71, 95% CI 1.62 to 13.8) for pain intensity, respectively. Very-low and low-certainty evidence suggested no difference in adverse events between LLE-BFR and LLE (risk ratio, RR=0.92) or HLE (RR=1.08); however, adverse-event monitoring and reporting were inconsistent across trials. Conclusion Low-certainty evidence indicates that LLE-BFR improves muscle strength and disability compared with LLE. Moderate-certainty evidence showed no clear difference in muscle strength compared with HLE, while evidence for disability was very low certainty, precluding firm conclusions. Prediction intervals were wide for several outcomes. Although pain reductions favoured LLE-BFR, these effects were small and unlikely to be clinically meaningful, and evidence regarding adverse events remains limited. PROSPERO registration number CRD42023423638.

To synthesize evidence from systematic reviews on the effects of blood flow restriction (BFR) training on muscle strength, hypertrophy, and functional performance in older adults. An umbrella review was conducted after a comprehensive search in PubMed, Scopus, SPORTDiscus, and Web of Science until June 17, 2025. Eligible studies were systematic reviews, with or without meta-analyses, examining low-load BFR training in adults aged ≥ 50 years. Outcomes included muscle strength, hypertrophy, and physical function. Study selection and data extraction were performed independently by two reviewers, and methodological quality was assessed using AMSTAR 2. Twenty-three systematic reviews comprising 53 unique trials were included. Meta-analyses consistently indicated that BFR training promotes hypertrophy comparable to high-load resistance training (HL-RT) and superior to low-load training without BFR. Evidence on strength is mixed: some meta-analyses found gains similar to HL-RT, others reported inferior or superior results. Nevertheless, the majority of evidence suggests that BFR provides greater strength improvements compared to low-load training without BFR. Findings on functional performance were inconsistent. All reviews were rated as low or critically low in methodological quality. Across comparisons, heterogeneity and recurring methodological limitations-such as inadequate blinding and allocation concealment-were noted in primary studies. BFR training is a promising approach to enhance muscle strength and hypertrophy in older adults, but evidence certainty is limited by methodological weaknesses in both trials and reviews. Well-designed, high-quality studies are needed to confirm these effects and support clinical implementation.

As device features continue to evolve for use in BFR research and practice, it is critical for researchers and clinicians to understand how the existing literature supports -or fails to support -device-specific responses to BFR training. Rolnick (2024a) reported that multi-chambered bladder cuff designs largely prevent meaningful arterial occlusion and therefore cannot reliably individualize applied pressure relative to an individual's arterial occlusion pressure (AOP) (Rolnick, 2024a). Consequently, these cuffs may lead to systematic overestimation of the effective pressure experienced by participants when implemented in research settings or in those attempting to determine a pressure-dependent relationship on physiological outcomes such as cortical activation and cerebral oxygenation (Rolnick, Clarkson, et al., 2024). This limitation becomes particularly problematic when studies attempt to relativize pressure using limbcircumference-based algorithms developed for single-chambered cuffs, potentially producing a BFR stimulus that is substantially lower than intended.To illustrate the potential differences in acute physiologic stress associated with multichambered cuffs, Rolnick et al. (2024) compared fatiguability, central stiffness responses, and perceptual demands during lower-body BFR exercise with a single-chambered BFR cuff inflated to 60% supine AOP versus a multi-chambered bladder inflated to 300 mmHg (Rolnick, de Queiros, et al., 2024). The findings demonstrated that bladder design materially alters performance, perceptual, and vascular responses to BFR exercise and should be considered in BFR methodologies (Rolnick, de Queiros, et al., 2024). Stray-Gundersen and Stampley (2025) further discuss nuances associated with this multi-chambered cuff design in a narrative review and provide practical application guidelines informed by the existing body of research utilizing these systems (Stray-Gundersen & Stampley, 2025). Rolnick (2024b) additionally describes how autoregulation of applied BFR pressures by the device system itself may alter the acute BFR stimulus, drawing on divergent exercise performance outcomes observed in cohorts training with two different autoregulating BFR cuffs (Rolnick, 2024b). Importantly, the accompanying editorial cautions against making blanket statements regarding autoregulation, as the limited available evidence suggests that responsiveness may vary, thereby influencing acute physiological and performance responses to BFR exercise. Ogrezeanu et al. (2025) added clinical context by comparing autoregulated and non-autoregulated BFR at 50% AOP in patients with hemophilia (Ogrezeanu et al., 2025). Their findings showed trends towards more favorable acute cardiovascular and neuromuscular responses, including hypotensive and hypoalgesic effects with autoregulated BFR pressures, indicating that there may be benefit to implementing autoregulation when applying BFR within this cohort of patients.Finally, Rolnick, Stray-Gundersen, and de Queiros (2025) describe how the pressure set for BFR exercise does not always equal the pressure applied at the limb-cuff interface and outline the potential ramifications of this discrepancy for interpreting and implementing BFR training (Rolnick et al., 2025). Swain et al. (2025) provided empirical data on four commercially available BFR cuffs and reported that most were unable to consistently maintain interface pressure during exercise, with only the Delfi Personalized Tourniquet System maintaining set pressure within ±10% for most of the exercise bout (Swain et al., 2025). Further, despite targeting 80% AOP, some cuffs transiently applied pressures exceeding 100% AOP for up to 55% of the set, highlighting device-specific safety and dosage concerns. Bommasamudram et al. (2025) compared agreement between five different BFR devices for AOP values in supine and standing positions and found that no device demonstrated consistent agreement with the Zimmer surgical-grade cuff. However, posture-dependent changes in AOP underscore the need to consider body position when assessing and prescribing AOP (Bommasamudram et al., 2025). Lastly, Zhu et al. (2025) investigated the impact of varying percentages of AOP on muscle activation, post-exercise blood lactate, and perceptual demands. Their findings suggest pressure-dependent changes with increasing applied pressures and indicate that moderate pressures (~70% AOP) may elicit comparable physiological responses to higher pressures while imposing lower perceived exertion (Zhu et al., 2025). Rolnick, McEwen et al. (2024) provided critical commentary on a study with insufficient reporting of BFR methodology, emphasizing that when investigating the effects of pressure on physiological responses, comprehensive device reporting and appropriate study design are essential for valid interpretation (Rolnick, McEwen, et al., 2024).Other studies within this collection examined safety screening and pressure application, autonomic responses to varying pressures, cardiovascular responses in animal models, the integration of BFR with variable resistance training, and multiple systematic reviews and metaanalyses. Collectively, these works help contextualize how BFR and BFR-related methodological decisions influence both acute physiological responses and chronic training adaptations. Wedig et al. (2025a) reported on a web-based BFR implementation tool designed to assist practitioners with safety screening and reduce barriers to clinical and applied use (Wedig, Petushek, et al., 2025). The authors observed high usability with minimal errors and reported that users demonstrated greater confidence in BFR and an increased likelihood of implementation when using the tool, largely because it addressed previously identified barriers related to screening, equipment selection, and pressure determination (Rolnick et al., 2021). Additionally, Wedig et al. (2025b) investigated predictors of lower-limb AOP...

It is recommended to prescribe sets to volitional muscular failure (e.g., 4 sets) or a fixed repetition scheme of 75 repetitions (1 × 30, 3 × 15) in low-load resistance exercise with blood flow restriction (BFR-RE). While prior studies suggest both protocols may elicit similar muscular adaptations, the extent to which this is explained by matched exercise volume remains unclear. This systematic review and meta-analysis evaluated the number of repetitions performed during four sets of low-load BFR-RE to volitional muscular failure and compared these with the fixed 75-repetition scheme. The goal was to determine whether the two protocols yield similar total and per-set repetition volumes. On 10/31/2024, two databases (PubMed® and Scopus) were used to identify studies that applied a protocol of four sets to volitional muscular failure in BFR-RE with a load of ≤ 50% of one repetition maximum (1RM), regardless of the outcome investigated. Mean repetition data were pooled using a random-effects meta-analysis. One-sample t-tests compared per-set and total volumes to the reference scheme (1 × 30, 3 × 15). Across 25 studies (47 means; n = 678), the estimated total repetitions performed to failure was 73.1 (95% CI: 61.1 to 85.2). Per-set means were 36.0 (95% CI: 30.5 to 41.4), 14.7 (95% CI: 12.2 to 17.1), 11.5 (95% CI: 9.2 to 13.8), and 10.4 repetitions (95% CI: 8.1 to 12.7) for sets 1 through 4, respectively. Four sets of BFR-RE to volitional muscular failure produce similar total repetition volume compared to the commonly implemented fixed 75-repetition scheme, though the distribution of repetitions per set differs. These findings provide insight into the mechanical equivalence of two widely used BFR-RE prescriptions. This study demonstrates that performing four sets of low-load BFR-RE to volitional muscular failure yields similar total repetition volumes as the commonly studied and traditionally recommended fixed 75-repetition protocol (1 × 30, 3 × 15), despite meaningful differences in per-set repetition counts. Lower external loads and higher occlusion pressures were associated with slightly greater total repetitions—likely reflecting study design choices rather than physiological effects. Personalized pressure strategies affected repetitions achieved, with notable performance declines across later sets. These findings highlight the flexibility of BFR-RE prescription while underscoring the importance of fatigue management and set progression. The fixed 75-rep protocol may offer a more tolerable and practical option for many populations, particularly in rehabilitation or clinical settings where adherence is a key concern.

Blood flow restriction (BFR) training-defined as the use of external pressure to partially restrict arterial inflow and intermittently occlude venous return during low-load exercisecontinues to expand in both clinical and athletic settings (Scott et al., 2023). While continuing to evolve, there is increased attention being paid to how the BFR stimulus itself is impacted with different device features. Early literature focused on device features such as cuff width (Laurentino et al., 2016) and cuff material (Buckner et al., 2017) and their impact on acute responses and longitudinal adaptations to BFR exercise. Newer focus has shifted to autoregulation of applied BFR training pressures (Jacobs et al., 2023;Rolnick, De Queiros, et al., 2024;Rolnick, Licameli, et al., 2024), bladder design (Rolnick et al., 2025;Rolnick, de Queiros, et al., 2024), and cuff shape (Vehrs et al., 2024).However, one feature that is often not recognized but is receiving a growing amount of attention is the set/interface pressure capabilities of a BFR cuff (Hughes et al., 2018(Hughes et al., , 2024;;Neal et al., 2023). This BFR device feature focuses on the stability through which pressure is delivered to the limb and monitored during BFR exercise. The "set pressure" is the pressure that is set by the user whereas the "interface pressure" is the actual pressure exerted by the cuff on the surface of the limb (Rolnick et al., 2023). For example, the set pressure prescribed during BFR exercise could be measured at 200 mmHg which could equate to 80% of the intended limb occlusion pressure (LOP) -the minimum amount of pressure to fully occlude blood flow to a limb and is the typically recommended way single-chambered non-elastic BFR cuffs apply pressure in BFR exercise (Jessee et al., 2016;Patterson et al., 2019). All commercially available BFR devices report the applied pressure to the limb in the units of mmHg, making these units the most accessible to providers and researchers to measure the set pressure. On the other hand, interface pressure has not been reported outside of methodological studies (Hughes et al., 2018(Hughes et al., , 2024) ) as it requires specialized equipment such as pressure sensors embedded within the BFR cuff or fastened to the underlying limb (Hughes et al., 2018(Hughes et al., , 2024;;Neal et al., 2023). Therefore, counter to set pressure, those practicing BFR do not have access to interface pressure data other than what can be inferred by one of three existing studies (Hughes et al., 2018(Hughes et al., , 2024;;Neal et al., 2023).It could be reasonably hypothesized that the interface pressure, rather than set pressure, more closely relates to the physiological stimulus imposed by BFR as it is more representative of the force exerted upon the limb during exercise, whereas set pressure is a resting value that is dependent on material, width, ability to autoregulate, bladder design etc. (Hughes et al., 2024). A non-elastic BFR cuff capable of maintaining a consistent set/interface pressure could be advantageous in research settings to decrease intra-and inter-participant variability to a BFR intervention, mitigate vascular or nervous system stress, and possibly, enhance longitudinal responses.To date, three publications have implemented some form of set/interface pressure monitoring into their methodology (Hughes et al., 2018(Hughes et al., , 2024;;Neal et al., 2023) (Table 1). Two of them investigated the impact of different BFR cuffs on both physiological and perceptual (Hughes et al., 2018) and maintenance of set/interface pressure prior to, during, and postexercise (Hughes et al., 2018(Hughes et al., , 2024)). The third employed a strap-based BFR cuff and sought to determine the relative magnitude of pressure applied to the limb under different strap settings (Neal et al., 2023). Evidence from Hughes et al. (2018Hughes et al. ( ,2024) ) indicates that only one BFR device -the Delfi Personalized Tourniquet System (PTS) -has the capability to regulate the set pressure effectively to allow for a consistent interface pressure at rest, during exercise, and immediately post-exercise 100% of the time (Hughes et al., 2018(Hughes et al., , 2024)). Other cuffs have shown large variations in their capacity to maintain a consistent pressure on the limb throughout exercise and have exhibited pressure drifts between the set/interface settings (Hughes et al., 2018(Hughes et al., , 2024)). In a recent study, only one other cuff -Suji BFR -was able to maintain mean pressure on the limb post-exercise, albeit with higher variability than the Delfi PTS (Hughes et al., 2024). Other commercially available cuffs including SmartCuffs, B Strong, and Saga Fitness were under pressurized post-exercise and were only able to maintain set/interface pressure consistently 43-68% of the exercise duration (Hughes et al., 2024). Neal et al. (2023) reported on the average applied pressure using the Hytro BFR wearable clothing with mostly mild variability (< 15 mmHg) in applied pressure in all 5 strap settings. However, the absence of understanding the set pressure due to the elastic, practical-based nature of the BFR cuff limits its applicability in the current discussion. Collectively, these findings suggest that interface pressure regulation may play a critical role in the consistency, safety, and physiological effectiveness of BFR application and warrants greater consideration in both research design and practical implementation.Insert Table 1 HereDespite limited evidence, considering the large variability between set and interface pressures that has been identified across devices, calls for improved stability between these variables seems reasonable, particularly as BFR is increasingly used in more and more clinical contexts (Hughes et al., 2024). Interface pressure is recognized as an important component of BFR application, yet consensus on how it should be measured remains lacking. Across the available studies,...