Safford Daniel W, Shah Kshamata M, Breidenbach Frederic, McClure Philip W
Physical Therapy Arcadia University.
Int J Sports Phys Ther. 2024 Jun 1;19(6):735-744. doi: 10.26603/001c.118143. eCollection 2024.
The rotator cuff (RC) plays a pivotal role in the performance and health of the shoulder and upper extremity. Blood flow restriction training (BFRT) is a modality to improve strength and muscle hypertrophy with even low-load training in healthy and injured individuals. There is minimal evidence examining its effect proximal to the occluded area, and particularly on the RC.
HYPOTHESIS & PURPOSE: The purpose of this case series is to explore the effects of low-load BFRT on RC strength, hypertrophy, and tendon thickness in asymptomatic individuals.
Case series.
Fourteen participants with asymptomatic, untrained shoulders were recruited to participate. They performed an eight-week low-load shoulder exercise regimen where BFR was applied to the dominant arm only during exercise. The dependent variables were maximal isometric strength of the shoulder external rotators(ER) and elevators (in the scapular plane in full can position) (FC) measured via handheld dynamometry, cross sectional area (CSA) of the supraspinatus and infraspinatus muscles, and supraspinatus tendon thickness measured via ultrasound imaging (US). Mean changes within and between arms were compared after training using paired t-tests. Cohen's d was used to determine effect sizes.
All participants were able to complete the BFRT regimen without adverse effects. Mean strength and CSA increased for all variables in both arms, however this increase was only significant (p<0.01) for FC strength bilaterally and CSA for the supraspinatus and infraspinatus on the BFRT side. The effect sizes for increased supraspinatus and infraspinatus CSA on the BFRT side were 0.40 (9.8% increase) and 0.46 (11.7% increase) respectively. There were no significant differences when comparing the mean changes of the BFRT side to the non-BFRT side for strength or muscle CSA. There were no significant changes to supraspinatus tendon thickness.
These results suggest variability in response of the RC musculature to low-load BFRT in asymptomatic individuals. The potential for a confounding systemic response in the study design makes determining whether low-load BFRT is more beneficial than low-load non-BFRT difficult. The hypertrophy seen on the BFRT side warrants further study.
肩袖（RC）在肩部和上肢的功能及健康方面起着关键作用。血流限制训练（BFRT）是一种即使在低负荷训练时也能提高力量和肌肉肥大的方法，适用于健康个体和受伤个体。关于其在闭塞区域近端的影响，尤其是对肩袖的影响，证据极少。
本病例系列的目的是探讨低负荷BFRT对无症状个体肩袖力量、肥大及肌腱厚度的影响。
病例系列。
招募了14名肩部无症状且未经训练的参与者。他们进行了为期八周的低负荷肩部锻炼方案，其中仅在锻炼时对优势臂施加血流限制。通过手持测力计测量的因变量包括肩部外旋肌（ER）和上举肌（在肩胛平面全罐位）（FC）的最大等长力量，通过超声成像（US）测量的冈上肌和冈下肌的横截面积（CSA）以及冈上肌腱厚度。训练后，使用配对t检验比较双臂内和双臂间的平均变化。使用科恩d值来确定效应大小。
所有参与者都能够完成BFRT方案且无不良反应。双臂中所有变量的平均力量和CSA均增加，但仅双侧FC力量以及BFRT侧冈上肌和冈下肌的CSA增加显著（p<0.01）。BFRT侧冈上肌和冈下肌CSA增加的效应大小分别为0.40（增加9.8%）和0.46（增加11.7%）。比较BFRT侧与非BFRT侧在力量或肌肉CSA方面的平均变化时，无显著差异。冈上肌腱厚度无显著变化。
这些结果表明，无症状个体的肩袖肌肉组织对低负荷BFRT的反应存在差异。研究设计中潜在的混杂全身反应使得难以确定低负荷BFRT是否比低负荷非BFRT更有益。BFRT侧出现的肥大值得进一步研究。
4级。
