Effect of standard and Aircast tennis elbow bands on integrated electromyography of forearm extensor musculature proximal to the bands

Abstract

Classic tennis elbow, or lateral epicondylitis, has been described as an overuse or misuse injury resulting in a tendinitis. The extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC) have been impli cated as primary culprits in this pathology. Tennis elbow has been treated using a constrictive band placed several centimeters distal to the origin of these two muscles. Aircast (Aircast Inc., Summit, NJ) has devel oped a new style of band that employs an air-filled bladder as the counterpressure element. This study tested the effect of both standard and Aircast bands on EMG activity of the EDC and ECRB proximal to the band compared to control values. Ten normal subjects, ranging in age from 20 to 43 years, were tested. Right upper extremities were tested in all cases. The subjects' forearms were stabilized in the CYBEX II forearm stabilization V-pad. The ECRB and EDC were then impaled with monopolar EMG needle electrodes. The CYBEX data were recorded using the HUMAC system and the EMG data were recorded and analyzed using the Cadwell 7400. EMG data were recorded at 80% of maximum voluntary isometric contraction (MVIC) with no band, the standard band, and the Aircast band. An analysis of variance (ANOVA) with repeated meas ures of integrated EMG (IEMG) and Duncan's multiple comparison tests revealed that the Aircast caused a significant reduction in IEMG of the ECRB and EDC when compared with control values and the standard band. The decrease in IEMG with the standard band was not statistically significant. This may begin to pro vide an explanation for the anecdotal reports of the clinical effectiveness of the air-bladder type of counter force bracing.