The forearm support band is hypothesized to reduce force, and thus inflammation, at the extensor carpi radialis brevis (ECRB) origin. Very little published evidence supports an actual effect on the forces at the ECRB origin, however. The authors describe a cadaveric study in which forces at the ECRB origin were measured while various pressures were applied to the forearm support band and the ECRB tendon was loaded distally. The results reveal an increased effect with increased band pressure and a decreased relative effect with increased force applied distally. For clinical correlation, application pressure was also measured in nine patients using a counterforce brace. While further clinical evaluation is necessary to determine the most appropriate clinical indications for use of a forearm support band, these results suggest that the forearm support band may be most effective when applied at a force of 40 to 50 mmHg and used during light-duty activities.