Date of Award

6-2024

Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)

Department

Physical Therapy

First Advisor

Gary Schindler

Keywords

Blood flow restriction therapy (BFR), Muscular hypertrophy, Vascular occlusion, muscle electromyography (EMG), infraspinatus (INFRA),extensor carpi radialis brevis (ECRB), external rotation (ER).

Abstract

Purpose/Hypothesis: Blood flow restriction therapy (BFR) has become a popular strength training and intervention method. Research shows BFR increases muscular hypertrophy and strength, mostly attributed to vascular occlusion. The purpose of this study is to examine BFR effects on proximal and distal muscle electromyography (EMG) activity to evaluate characteristics of fatigue in the infraspinatus (INFRA) and extensor carpi radialis brevis (ECRB) during resistive side-lying shoulder external rotation (ER). Number of Subjects: 51

Materials/Methods: Fifty-one college students, 31 females, and 20 males participated in the study. Shoulder ER peak force was identified in side-lying utilizing a MicroFET. Participants completed shoulder ER at 20% of the recorded peak force. Surface EMG electrodes were placed on the INFRA and ECRB muscles. Participants completed 2 trials of shoulder ER in side-lying with and without BFR with a 30-minute rest period between trials. A trial ended upon volitional fatigue or when 2 incorrect repetitions were observed. EMG data were collected and analyzed using Noraxon MyoResearch software. A repeated measures pairwise comparison analysis was performed on the EMG frequency slope, mean frequency, and mean amplitude using SPSS.

Results: Significant differences (p < .001) were noted in average repetitions with BFR (34.5 reps) and without BFR (44.6 reps). The slope of the EMG frequency was negative for muscles in both conditions with statistical significance (p

Conclusion:This study demonstrated increased shoulder ER repetitions without BFR compared to utilizing BFR. The INFRA and ECRB muscles demonstrated similar EMG amplitude changes; however, the frequency was more negative with BFR along the ECRB. The slope of frequency was significant (p

Clinical Relevance: Research identifies the benefits of various BFR protocols on distal musculature; however, there is limited research for muscles proximal to the occlusion cuff. Determining the effects various BFR application protocols may have on proximal musculature could assist in rehabilitation programming that optimizes BFR effects in the treatment of UE pathologies.

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