Date of Award


Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Advisor

Thomas Mohr


Electromyography -- methods; Movement Disorders -- physiopathology; Scapula -- physiopathology; Case Reports


Introduction and Purpose. The purpose of this case study was to examine the differences in muscle activation between the upper trapezius, middle trapezius, lower trapezius and serratus anterior in a participant with scapular dyskinesia.

Methods. EMG activity was recorded using a Noraxon TeleMyo DTS telemetry unit with a sampling rate of 1 kHz. EMG data was recorded during three different speeds of shoulder abduction. Four scapular muscles were monitored bilaterally during the experiment. The muscles that were monitored included the upper trapezius, middle trapezius, lower trapezius and serratus anterior. The subject was also captured on video using the NiNox 125/250 FPS camera system.

Results. In comparing UE ratios of EMG activity, it appears that the left lower trapezius showed more EMG activity than the right lower trapezius. The left serratus anterior showed decreased activity relative to the trapezius muscle activity. The decreased activity in the left serratus anterior would help explain the scapular winging that occurred in the subject during shoulder elevation .

Conclusion. The results of this study indicate that the subject showed increased EMG activity in the left lower trapezius and decreased in the left serratus anterior that might explain the scapular dyskinesia. The use of EMG and video may be a useful diagnostic tool for clinicians to identify specific muscle firing patterns.