Blood Flow Restriction Therapy for Stimulating Skeletal Muscle Growth: Practical Considerations for Maximizing Recovery in Clinical Rehabilitation Settings

Abstract

Inactivity following injury and surgery due to pain, instability, or immobilization results in loss of muscle mass and function. As a result, both risk of reinjury and overall recovery time are a prime concern for clinicians and therapists trying to minimize these deleterious effects. While resistance exercise has been demonstrated to be highly effective in combating loss of muscle mass and function, it is often not advised for postoperative or injured patients because of elevated risk of injury or exacerbating existing injury sites. Low-intensity resistance exercise (<30% 1 repetition-maximum) performed with mild to moderate blood flow restriction (BFR) has been observed to elicit beneficial anabolic and functional responses in skeletal muscle that are governed by mechanisms that regulate muscle protein metabolism and myogenesis similar to the responses following high-intensity resistance exercise. On the basis of these findings, practical applications of BFR in clinical and sport settings have been developed to mitigate skeletal muscle loss following injury and accelerate rehabilitation. However, many aspects of the physiological effects of BFR therapy in rehabilitation settings remain unclear. This review provides current information regarding skeletal muscle responses to BFR with a focus on skeletal muscle protein metabolism, anabolic signaling, applied outcomes, and applications in the clinical setting.

The effect of low‐load resistance training with blood flow restriction on chronic patellar tendinopathy — A case series

“…Lately, the use of low-intensity (20-40% 1RM) resistance training in combination with blood flow restriction (BFR) has been advocated as a clinically relevant rehabilitation tool for patients not tolerating high muscle-tendon loads 17,18 . Of note, prospective studies have reported similar or improved clinical outcomes after BFR exercise compared to conventional rehabilitation following various types of knee injury [19][20][21][22] .…”

Blood Flow Restriction Training for the Shoulder: A Case for Proximal Benefit

“…12,29,40,56 Although many of the mechanisms by which BFR may act on skeletal muscle remain under investigation, In-Depth previous reports indicate that performing low-intensity exercise under occluded conditions acutely stimulates muscle anabolism primarily via mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin complex 1 (mTORC1) intramuscular signaling pathways; these pathways regulate skeletal muscle responses to metabolic and mechanical stress as well as signaling via the sensing of effectors released from contracting muscle or systemically that act in an autocrine, paracrine, or systemic fashion. 22,23,25,26,36 When performing low-intensity exercise with BFR, muscles are often exercised to fatigue in a manner that, due to the partial occlusion, temporarily prevents the removal of lactate, calcium, and other metabolites that may reduce intracellular and local blood pH and contribute to stress signaling. 36 This occurrence combined with increased muscle fiber recruitment due to fatigue, structural strain from muscle cell swelling, and release of signaling effectors from muscle (eg, myokines, local insulin-like growth factors [IGFs], microRNA) has been hypothesized to directly and indirectly stimulate muscle anabolism via the aforementioned signaling pathways in concurrence with other mechanisms involved in the regulation of cell growth and degradation.…”

“…22,23,25,26,36 When performing low-intensity exercise with BFR, muscles are often exercised to fatigue in a manner that, due to the partial occlusion, temporarily prevents the removal of lactate, calcium, and other metabolites that may reduce intracellular and local blood pH and contribute to stress signaling. 36 This occurrence combined with increased muscle fiber recruitment due to fatigue, structural strain from muscle cell swelling, and release of signaling effectors from muscle (eg, myokines, local insulin-like growth factors [IGFs], microRNA) has been hypothesized to directly and indirectly stimulate muscle anabolism via the aforementioned signaling pathways in concurrence with other mechanisms involved in the regulation of cell growth and degradation. 1,20,25,39,55,60 Because metabolic and mechanical stress is primarily experienced by muscles distal to the site of occlusion, one may speculate that proximal muscles (where blood flow is not occluded) may not experience the same stimulatory effects with regard to changes in strength and muscle mass.…”

“…However, it has been postulated that BFR can provide benefits to muscle groups directly proximal to the site of occlusion via local paracrine or systemic action as well as elevated muscle fiber recruitment. 19,36 Although BFR therapy is becoming popular in sports and military rehabilitation, current therapy protocols are based on limited data from short-term investigations, and adequate longitudinal studies are lacking. 36 Importantly, rehabilitation and injury prevention protocols for the upper extremities (particularly the shoulder) are currently underdeveloped, and hard data regarding the efficacy of BFR beyond anecdotal reporting are extremely limited.…”

“…19,36 Although BFR therapy is becoming popular in sports and military rehabilitation, current therapy protocols are based on limited data from short-term investigations, and adequate longitudinal studies are lacking. 36 Importantly, rehabilitation and injury prevention protocols for the upper extremities (particularly the shoulder) are currently underdeveloped, and hard data regarding the efficacy of BFR beyond anecdotal reporting are extremely limited. 36 Although promising results have been reported for the use of BFR for upper body rehabilitation, controlled studies on the effects of BFR for rehabilitation or preventive training on the rotator cuff or shoulder musculature as a whole are insufficient.…”