Six healthy subjects were studied to determine the optimal size, shape and placement of stimulating electrodes during the application of electrical stimulation (ES) to the biceps, quadriceps, and tibialis anterior muscles. Subjects were recruited to allow for diversity in age, sex, and skin pigmentation. Subjects sat in a custom designed multi-positional chair, which allowed precise positioning of each extremity. After determining the maximal voluntary contraction (MVC) of the muscle and careful determination of the motor point, ES, with a biphasic square wave of 300 ms duration and a frequency of 30 Hz, was used to bring the muscle to 10% MVC. Subject tolerance to ES was recorded using a visual analogue pain scale (VAS) and autonomic measures of heart rate, blood flow, galvanic skin resistance, and skin temperature. The electrical current required (ESi) and VAS pain scores were analyzed using a repeated measure ANOVA. Autonomic measures were correlated with VAS pain scores using Pearson’s correlation coefficients. The analysis revealed significant increases in ESi and VAS scores for placements away from the motor point, but no significant differences in ESi and VAS scores with electrode size and shape. Specifically, there was a significant increase in ESi and or pain values when the electrode was moved medially and laterally on the biceps, distally and medially on the quadriceps, and distally and laterally on the TA. Autonomic functions showed no significant correlations with current requirements or VAS scores. This data supports the importance of determining the motor point before placing the stimulating electrode pad for the administration of ES.
Key Words: Electrical stimulation, motor point, FES, pain, strength, training.
School of Allied Health Professions
Jerrold S. Petrofsky
Grenith J. Zimmerman
Doctor of Physical Therapy (DPT)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Electrodes -- therapeutic use; Electric Stimulation Therapy.
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Forrester, Bonnie J., "Effect of Electrode Size, Shape, and Placement on Electrical Current and Subject Comfort During Electrical Stimulation" (2002). Loma Linda University Electronic Theses, Dissertations & Projects. 794.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives