Background: Decreased muscle mass and altered joint mechanics are connected to the development, course, and severity of knee osteoarthritis. The hamstring muscles tend to shorten and contract, which increases the patello-femoral compressive force. Particularly for the hamstrings, stretches and percussive massage might help lessen the limitation of knee extension that is seen in patients with knee osteoarthritis. Purpose: Examine how utilizing a percussion massage gun affects people with knee osteoarthritis' hamstring flexibility, discomfort, range of motion, and function. Methods:  Forty two patients, ranging in age from 45 to 60 years, of both genders and mild to moderate knee OA were randomly assigned into two groups with 21 subjects in each. Group A, or the control group, underwent traditional physical therapy treatment. including stretching and strengthening of the lower limb muscles three sessions per week for four weeks, Group B (experimental group): received the same exercise as group A in addition to percussion massage gun on the hamstrings for five minutes three sessions per week for four weeks, Sit and Reach test to assess hamstring flexibility, VAS for pain., Active knee extension for knee extension ROM and WOMAC questionnaire to assess knee joint function.
Results: study results revealed significant improvement (P<0.05) in hamstrings flexibility, pain, ROM and function in group B compared to group A. Conclusions: study results confirmed the effective role of the using traditional physical therapy program in combination with the percussion massage gun on the hamstrings flexibility, pain, knee ROM and Function.