Instrument-assisted soft tissue mobilization (IASTM) tools are used during rehabilitative care for treatment of injuries to muscles, tendons, and ligaments. Many studies have quantified treatment application forces between tools and the patient. However, the effect of force on the clinician has not been studied even though research shows that clinicians experience discomfort and fatigue during treatment. This work presents a method to accurately measure the pressure profile between the IASTM tool handle and hand of the clinician. Flexible pressure indicating film was used to measure the pressure magnitude and distribution on the hand. These tests were performed at varying treatment application forces between 15 and 60 N, normal to the treatment surface. The tests were repeated, and forces were compared between 3D-printed designs. The pressure profile on the user was explored by changing aspects of the handle design. Results are analyzed and discussed as an effect of changing handle dimensions. As the diameter of the handle increased, the pressure magnitude decreased while the pressure distribution across the hand increased. Changing the contour of the handle further decreased the magnitude and increased the distribution. This procedure is not specific to the chosen tool and can be repeated for other tools.