The Elbow-EpiTrainer: a method of delivering graded resistance to the extensor carpi radialis brevis.

Tennis elbow or lateral epicondylopathy (LE) is experienced as the lateral elbow has a reported prevalence of 1.3%, with symptoms persisting for as long as 18 months. LE is most often attributed to tendinopathy involving the extensor carpi radialis brevis (ECRB) tendon. The goal of tendinopathy management is to alleviate symptoms and restore function that initially involves relative rest followed by progressive therapeutic exercise. This study was to assess the effectiveness of two prototype exercises using widely available clinical equipment to progressively increase resistance and activity of the ECRB. Eighteen healthy participants performed two exercise progressions. Surface electromyography was used to record ECRB activity during the two progressions, involving eccentric exercises of the wrist extensors and elbow pronation exercises using a prototype device. The two progressions were assessed for their linearity of progression using repeated ANOVA and linear regression analysis. Five participants repeated the study to assess reliability. The exercise progressions led to an increase in ECRB electromyographic (EMG) activity (p<0.001). A select progression of exercises combining the two protocols increased EMG activity in a linear fashion (p<0.001). The ICC values indicated good reliability (ICC>0.7) between the first and second tests for five participants.

The study found that manipulation of resistance and leverage with the prototype exercises was effective in creating significant increases of ECRB normalised EMG activity in a linear manner that could, with additional research, become useful to clinicians treating LE. In addition, between trial reliability for the device to generate a consistent load was acceptable.