The Effects of Shoulder Position on Bicep Brachii Activation

Abstract

Record ID: 264

Award(s): Excellence in Undergraduate Research Mentorship

Program Affiliation: Capstone

Presentation Type: Poster

Abstract: Our study aims to investigate how different shoulder positions affect the activation of the biceps brachii muscle during bicep flexion resistance exercises. Limited research shows that shoulder position from extended to neutral to flexed changes biceps activations. Here we use electromyography (EMG) to identify which shoulder position elicits the greatest relative activation (i.e., electrical activity produced by the muscle). The EMG of the biceps brachii will be measured in shoulder extension, anatomical position, and shoulder flexion. The EMG data will be derived from an elbow flexion curl exercise and a metronome will be used to keep consistent speed of repetitions. We anticipate that performing a bicep curl with the shoulder in an extended position will produce the greatest EMG activation due to the reduced force generating capabilities in an extended position. This extended position would have increased biceps activations from having to recruit more muscle fibers to complete the biceps curl with the relative external load and the induced stretch of the biceps from the initial starting position.  Results of this study can be used to inform strength training and rehabilitation programs.