PL18

EMG ANALYSIS OF 4 MUSCLES DURING 3 PRESCRIBED CORE STABILIZATION EXERCISES

Brajuha DA, Nitz AJ, Uhl TL, Mattacola CG

University of Kentucky, Department of Rehabilitation Sciences, Lexington, KY
Session A, Thursday, February 13, 2003 4:15 PM-4:30 PM

     Purpose: Great emphasis is given in rehabilitation to enhancing core strength, stability, and control though limited research is available to document the efficacy of such efforts. The purpose of this study was to determine the effectiveness of 3 prescribed exercises in activating 4 known core-stabilizing muscles: external abdominal oblique, gluteus medius, multifidus, and erector spinae.

    Methods: Fifteen healthy college students with pain-free, full lumbar spine range of motion volunteered for this study. Surface bipolar electrodes were applied to the external abdominal oblique, the gluteus medius, and erector spinae while fine wire bipolar intramuscular electrodes were inserted into the multifidus muscle. Core-stabilizing muscle activation was assessed in the 4 muscles while performing specific exercises using a Swiss Physioball®, Dynamic Edge®, and a standard mat exercise. Data were analyzed by repeated measures ANOVA statistical procedures for comparison of percentage of maximum voluntary isometric contraction or higher (MVIC), percentage of time all 4 muscles were active at 25% MVIC or higher (coactivation), and the percentage of coactivation of trunk muscles alone (gluteus medius muscle excluded).

    Results: Preliminary data analysis of a subset of the participants indicates wide variability in subject response, though certain trends were identified. Specifically, the erector spinae and multifidus were more active than either the external oblique or gluteus medius across all 3 exercise conditions. Exercises using the Dynamic Edge® exercise device were more demanding for coactivation of trunk muscles than the mat exercise or those accomplished using the Swiss Physioball®. In particular, the external oblique muscle was considerably more active when subjects were performing trunk stabilization exercise using the Dynamic Edge®. As anticipated, the gluteus medius was the least active of the muscles during trunk stabilization activities examined in this study.

    Conclusion: The results of our research indicate that substantial trunk stabilization (coactivation) does occur during a variety of common exercise conditions. Certain exercises and test conditions were more demanding than others, especially for specific muscles such as the erector spinae, multifidus, and external oblique. The Dynamic Edge® device appears to be more demanding for core stabilization muscles than either the mat exercise or those accomplished using the Swiss Physioball®.

    Relevance: Documentation of trunk muscle coactivation (core stabilization) is needed to provide clinicians guidance when developing exercise regimens for patients requiring such intervention. Further research is required to establish the clinical effect of applying such exercises to patients treated with trunk stabilization exercises.

Reprinted from Orthopaedic Section Research Abstracts, Abstract #PL18. J Ortho Sports Phys Ther. 2003; 33(2):A-7, with permission of the Orthopaedic and Sports Physical Therapy Sections of the American Physical Therapy Association.