Study of finger force variability for physical therapists and untrained subjects

Physical therapy exercises often involve a patient exerting a force on an object. When a physical therapist shows a patient how much force to exert, the patient may or may not be able to accurately replicate at home what they were shown in the clinic. We study the ability of therapists and of untrained subjects to exert a steady force. Force is measured using a fingertip pressure sensor. We also study the ability to remember and repeat a force value previously maintained. In the absence of real-time visual feedback of achieved force, untrained subjects do less well than physical therapists at holding steady values and at remembering and repeating a previously held value. We introduce a measure of the rapidity of matching success, and find its relation to baseline pressure values.