A patient can undergo physical therapy to rehabilitate a musculoskeletal condition. The success of the rehabilitation relies in part on whether the patient uses an exercise band with the correct resistance for their condition. In order to select the correct resistance, a controller can instruct the patient to perform a directed movement with an exercise band, receive exercise data from at least one sensor (e.g., a camera, like a front-facing camera, that records the patient, a plurality of sensors on or near the patient's skin, etc.) as the subject performs the directed movement, and calculate a pull force exerted by the patient on the exercise band based on at least a portion of the exercise data. The adequacy of an exercise with the exercise band for the patient is determined based on the pull force can be determined based on the calculated pull force.