Effect of shortwave diathermy on the electromyographic activity of the rectus femoris and vastus medialis muscles

ABSTRACT

To study the effect of deep heating produced by a 30 minute application of shortwave diathermy on the maximal electromyographic [EMG] activity of the rectus femoris and vastus medialis muscles. Twenty-one normal subjects participated in this study. They were tested before and immediately after the application of shortwave diathermy by using a dual channel surface recording EMG equipment. The testing procedure consisted of 5 consecutive repetitions of knee extension against maximal mechanical resistance. There was a significant reduction [p< 0.005] of the maximal EMG activity if the vastus medialis muscle and a non-significant reduction [p> 0.05] of the maximal EMG activity of the rectus femoris muscle. It is suggested that follow up evaluations of the quadriceps muscle strength should not be performed immediately after the application of shoetwave diathermy. It is also, advised not to do strengthening exercises for the quadriceps immediately following such treatment which is common in physical therapy practice