The Association Between Muscle Contraction Ratings from Manual Muscle Testing Performed by Pre-physical Therapy Students and Electromyography Readings Obtained from Isometric Contractions

Abstract

INTRODUCTION: Manual muscle testing (MMT) is utilized in different fields like physical therapy and other fields that require diagnosis of a person’s muscular strength and progression over time. MMT involves stabilization of a certain part of the body while external resistance is provided by the manual muscle tester. Muscular activity is graded on a 0 to 5 scale. Another way to measure muscle activation is by electromyography (EMG). EMG uses electrodes to record electrical activity produced by a muscle. PURPOSE: The purpose of the study was to determine the relationship between ratings of muscular activity by pre-physical therapy students and actual EMG readings on the peroneus longus. METHOD: Eight subjects (4 males and 4 females) from the Kinesiology department at UTA volunteered to participate in this study. Subjects practiced MMT of the peroneus longus on one another and completed an isokinetic contraction test on the Biodex on the first day of the study. During the second day, subjects were asked to perform a MMT and rate the contraction either 25%, 50%, 75%, or 100%. The subject contracting the peroneus longus was contracting by attempting to match the reference line on the computer. Without looking at the computer where the percent of contraction was displayed, the manual muscle tester rated the contraction. RESULTS: Mean values for the peak torque, average power, and agonist/antagonist ratio on the Biodex were 10.7 ± 2.88, 14.4 ± 3.82, and 85.6 ± 16.09 respectively. Alpha level was set at .05 to test for significance between EMG readings and manual muscle tester ratings. Data were analyzed with SPSS 21 by using intraclass correlation coefficient (ICC) using a two factor mixed effects model and absolute agreement. With the Wilcoxon Signed Rank Test, a p value of 1.00 was established. Since the p value was greater than .05, significant difference in ratings from EMG and manual muscle testers were not found. CONCLUSION: The results of this study indicated that there was no significant difference in EMG readings and manual muscle tester ratings performed by pre-physical therapy students on the peroneus longus.