Date of Award

5-2026

Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)

Department

Physical Therapy

First Advisor

Gary Schindler

Abstract

Purpose/Hypothesis: Blood flow restriction (BFR) is a method of training that utilizes a tourniquet style cuff to limit the amount of blood flow to a working muscle during exercise. This method of training allows an individual to train at lower intensities while still gaining similar results to more traditional types of training. It has been shown in research that low intensity BFR has several benefits to structures distal to the level of the tourniquet, but minimal research has been conducted to investigate the benefits to proximal structures. This study is aimed at examining the proximal effects of BFR training on the infraspinatus muscle with respect to its cross-sectional area (CSA) and shoulder external rotation strength. It is hypothesized that the proximal effects of BFR training will show similar improvements in growth and strength as traditional training methods.

Materials/Methods: This study included 28 participants (age ranging 20 to 24 years old) that were recruited to the study and randomly assigned to one of three groups: a control group, a non-BFR training group, and a BFR training group. At the start of a 6-week period, initial CSA of the right-side infraspinatus muscle was measured using diagnostic ultrasound and peak right shoulder external rotation force was measured via handheld dynamometer. Participants in the BFR training group were assigned a weight resistance of 30% of their peak external rotation force while participants in the non-BFR group were prescribed a weight of 70% of their peak external rotation force. Control group participants did not complete any individual training for 6 weeks and were instructed to continue with their current level of activity. Participants used the Ancore portable resistance device to complete two (2) training sessions of four (4) sets (30/15/15/15 reps) per week for the 6-week time period. Participants in the BFR group used the Delphi BFR system. The Delphi system calculated each participant’s personal tourniquet pressure (PTP), which was 50% of the limb occlusion pressure in which to train. Following the training period, participants completed a post-testing of the infraspinatus CSA and shoulder external rotation force.

Results: Results of the study identified a positive relationship between BFR training and average cross-sectional area of infraspinatus muscle followed by the non-BFR and then the control group for average change. The non-BFR group demonstrated the greatest average improvement in shoulder external rotation strength, followed by the BFR group and the control group. Significant results were noted when comparing the shoulder external rotation force between the non-BFR and control group. No other significant values were observed.

Discussion: Statistically significant findings included an increase in peak force in the non-BFR group when compared to the control. In addition, the BFR group was able to elicit strength changes and a better average increase in infraspinatus CSA. These findings demonstrate that BFR training may cause similar muscle hypertrophy and strength gains as traditional resistance training, specifically when investigating structures proximal to the tourniquet cuff. However, BFR training should not be considered the lone training method when looking to increase strength and CSA muscle changes. Further studies should be conducted to further investigate the proximal and distal effects of BFR training on different joints and muscles.

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