Rotator cuff (RC) tendinopathy remains one of the most persistent and prevalent musculoskeletal disorders encountered in orthopaedic practice. While exercise therapy is the gold standard for management, clinicians often face a dilemma: how to load the tendon adequately for remodeling and strengthening without exacerbating pain. Recently, Blood Flow Restriction (BFR) training has surged in popularity as a potential solution, allowing for hypertrophy and strength gains at lower mechanical loads. A 2024 randomized controlled trial by Kara et al., published in the Clinical Journal of Sport Medicine, investigates whether low-load BFR offers superior outcomes compared to standard non-BFR training.
Study Protocol: Low-Load BFR vs. Standard Care
The study was designed as a randomized, assessor-blinded, controlled trial involving 28 participants diagnosed with rotator cuff tendinopathy. The patients were divided into two distinct groups for an 8-week rehabilitation protocol, attending sessions twice a week. One group engaged in low-load BFR training, while the control group performed the same exercise regimen without vascular occlusion.
The researchers utilized a comprehensive set of outcome measures, including ultrasound imaging to assess muscle thickness (supraspinatus, infraspinatus, deltoid, scapular retractors, and biceps), isokinetic dynamometry for internal (IR) and external rotation (ER) strength, and standardized questionnaires for shoulder pain and function.
Biceps Hypertrophy and Internal Rotation Strength: Where BFR Shines
The most distinct finding of this trial was the specific impact of BFR on the biceps brachii and shoulder internal rotation mechanics. The BFR group demonstrated a statistically significant greater increase in biceps muscle thickness (P = 0.002) compared to the non-BFR group. Additionally, the BFR group showed superior gains in shoulder internal rotation strength at 60 degrees/s (P = 0.040).
For physiotherapists, this is a clinically relevant finding. Given the role of the long head of the biceps as a dynamic stabilizer of the glenohumeral joint, the ability to preferentially hypertrophy this muscle group with low loads could be advantageous in specific rehabilitation phases, particularly when high-load internal rotation is provocative.
Pain and Function: Equivalent Clinical Improvements
While BFR demonstrated specific morphological benefits, it is crucial to note the outcomes regarding pain and general function. Both the BFR and the non-BFR groups experienced significant improvements in supraspinatus and infraspinatus muscle thickness, as well as External Rotation strength over the 8-week period.
Furthermore, shoulder pain decreased and functional scores improved significantly in both groups, with no statistical superiority observed in the BFR group. This suggests that while BFR is a potent tool, standard exercise therapy remains highly effective for the primary complaints of RC tendinopathy—pain and functional limitation.
Clinical Implications for the Physiotherapist
The results of this RCT suggest that low-load BFR is a viable, safe, and effective alternative to standard rehabilitation, particularly for patients who may not tolerate higher mechanical loads. While it may not drastically outperform standard care regarding pain reduction, its superior ability to improve biceps thickness and IR strength suggests it may be the modality of choice for patients exhibiting specific deficits in these areas. Clinicians should consider integrating BFR when traditional loading is limited by pain or when anterior shoulder stability (via biceps strengthening) is a priority.
References
Kara, D., Ozcakar, L., Demirci, S., Huri, G., & Duzgun, I. (2024). Blood Flow Restriction Training in Patients With Rotator Cuff Tendinopathy: A Randomized, Assessor-Blinded, Controlled Trial. Clinical Journal of Sport Medicine, 34(1). https://pubmed.ncbi.nlm.nih.gov/37706671/
