Inclusion Criteria:  Undergoing unilateral TKA surgery due to knee OA, Being between the ages of 50-75, To be able to understand the verbal and written information given.  Exclusion Criteria:  To undergo revision TKA surgery. Participating in any exercise or strengthening training within the last 3 months. Having undergone major surgery on the extremity to be operated on. Having a comorbid disease such as rheumatoid arthritis, cancer. Having a neurological disease that causes functional insufficiency. Having a diagnosed psychiatric disorder. Having received anaesthesia for any reason in the last 1 month. Regularly using hypnotics or anxiolytics. Having dementia. Having a hearing or vision impairment that cannot be corrected with a hearing aid or glasses. Being morbidly obese (Body mass index> 40 kg/m2). Having implanted pacemakers or defibrillators. Having dermatological problems affecting the thigh. Having a score above 3 in the American Society of Anesthesiologists classification score.