Date of Award


Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Advisor

Thomas Mohr


Electromyography; Lifting; Muscles -- physiology


PURPOSE: The purpose of this study was to assess if there was a change in electromyography (EMG) activity in the back or leg muscles when performing a dependent sit-to-stand lift before and after a brief proper lifting intervention.

SUBJECT: The subjects in this study included 10 female third-year doctoral physical therapy students from the University of North Dakota that were all in good health with no significant pathology of either their backs or lower extremities.

INSTRUMENTATION: The EMG activity was recorded by the Noraxon ™ TeleMyo 2400R G2 transmitter and a TeleMyo 2400 SG150 unit. Knee flexion was recorded via a Biometrics ™ Ltd Goniometer SG150.

PROCEDURE: The EMG activity was measured using surface electrodes over the right paraspinals, right quadriceps, and right hamstrings. An electrogoniometer was placed over the lateral portion of joint line of the right knee to capture knee flexion. Participants were instructed to perform a dependent sit-to-stand lift with no education on proper body mechanics to establish a baseline reading of muscle activity. EMG electrodes collected muscle activity that was generated during the dependent lift. Following education of proper body mechanics the procedure was repeated using the same dependent lift.

DATA ANALYSIS: MyoResearch XP computer software was used to analyze the EMG activity of each muscle group. The EMG software was given a theoretical maximum voluntary contraction via each muscle group. The EMG data was analyzed in comparison to this maximum voluntary contraction. The EMG data is analyzed through the entire lift.

RESULTS: The noteworthy results for this study conclude that on average the baseline maximum voluntary contraction of quadriceps was 41.60%, while the baseline maximum voluntary contraction of paraspinals was 93.07%. Following intervention, the maximum voluntary contraction of the quadriceps was 52.39%, while the maximum voluntary contraction of the paraspinals was 77.52%.

CLINICAL IMPLICATIONS: The results of this study indicate that following a brief training session on proper lifting technique, third-year physical therapy students demonstrated reduced EMG activity in paraspinal muscles and increased activity in the quadriceps muscles as compared to pre-training lifting.