Beneath the cuff: Often overlooked and under-reported blood flow restriction device features and their potential impact on practice—A review of the current state of the research

Abstract

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.

Autoregulated and Non-Autoregulated Blood Flow Restriction on Acute Arterial Stiffness

“…Our study reported high RPD in both BFR conditions compared to No-BFR with equal RPE. Lastly, our results conflict with a recent study investigating autoregulation of applied pressures using another commercially available BFR training device [26], indicating that acute responses to a BFR training program with autoregulation are possibly device-specific [20].…”

“…As BFR becomes more widely implemented in different practice settings [1], the availability of BFR equipment for consumer purchase has increased. However, there is a dearth of research available on the different types of BFR devices used, as well as features marketed to enhance its safety, tolerability, and/or efficacy during application [20]. One of those features is autoregulation of applied BFR pressures, whereby the applied pressure to the exercising limb from the BFR cuff is kept relatively constant compared to a manu-ally inflatable (non-autoregulated) cuff that does not adjust and, therefore, may heighten cardiovascular and perceptual exercise responses [21].…”

Impacts of Varying Blood Flow Restriction Cuff Size and Material on Arterial, Venous and Calf Muscle Pump-Mediated Blood Flow

“…To the authors' knowledge, the current study is interestingly the first to reliably and consistently assess narrow-elastic cuff AOP; the preponderance of preceding studies utilizing similarly designed Kaatsu bands have operated with a single standardized (i.e., arbitrary) pressure or were unable to dependably determine arterial occlusion amongst all participants [12,13,19,21,[38][39][40][41]. Moreover, employing arbitrary pressures may result in excessive arterial blood flow restriction and subsequently deleterious cardiovascular complications [5][6][7]42]. While these aforementioned investigations rarely exceed prescribed pressures of 300 mmHg, the current study illustrates that four participants reached or exceeded their AOP threshold (as high as 120% AOP) using the cuff manufacturer's arbitrary recommended pressure of 300 mmHg [38][39][40][41].…”

Important Methodological Concern Regarding the Article “Effect of Leg Half-Squat Training With Blood Flow Restriction Under Different External Loads on Strength and Vertical Jumping Performance in Well-Trained Volleyball Players”: A Letter to the Editor

“…Multichambered bladder devices are designed to reduce the potential for full arterial occlusion 7 and are not an appropriate device for integrating the AOP equation as it will likely greatly underestimate the applied pressure given its construction is designed to avoid the potential for such personalization of pressure. 8 Prior research has shown that the multi-chambered bladder system is unable to personalize pressures and has difficulty in modulating resting blood flow-factors that are likely important to inducing some of the beneficial effects of BFR exercise. Citherlet et al 7 showed that femoral blood flow was unaltered from resting conditions with pressures as high as 300 mmHg, a pressure that is almost double to that used in the current study (180 mmHg).…”

“…Multi-chambered bladder devices are designed to reduce the potential for full arterial occlusion 7 and are not an appropriate device for integrating the AOP equation as it will likely greatly underestimate the applied pressure given its construction is designed to avoid the potential for such personalization of pressure. 8…”