One of the most common joint disorders is hand osteoarthritis, which affects about 70% of people over the age of 35. The thumb accounts for a significant portion of the hand, and the carpometacarpal (CMC) joint is one of the most critical joints in the thumb. Recent research has shown that osteoarthritis (OA) can be seen as the end of a disease that begins with the loss of function and strength of the muscles surrounding the affected joint. To combat OA, re-education of the thumb muscles supporting the CMC joint can be used to increase stability. Prior studies have focused on separating muscle activation from range of motion or looked only at rehabilitation techniques for pain and strength without recording muscle activity. Our study aims to incorporate both aspects. Through the use of surface electromyography (sEMG), we can identify the activation of the First Dorsal Interosseous (FDI), the Abductor Pollicis Brevis (APB), the Abductor Pollicis Longus (APL), the Extensor Pollicis Brevis (EPB), and the Flexor Pollicis Brevis (FPB), key muscles in the function of the CMC joint. Our experiments explore the activation of these hand and forearm muscles during acts of daily living (ADLs) and through rehabilitation exercises. We have partnered with Kristina Miller, COTA/L OTS, who designed a dynamic exercise ball for rehabilitation to improve the symptoms of OA in the CMC joint. In future work, we hope to incorporate a motion capture system (MOCAP) to study the impact of OA and rehabilitation on the CMC joint range of motion. Overall, our research aims to use sEMG and MOCAP to measure the activation levels of the CMC joint supporting muscles and range of motion during ADLs. We also plan to use these techniques to evaluate the effectiveness of Miller’s rehabilitation device.