Pain during PROM is not due to the active shortening (contracting) of muscle and the resulting pull on tendon and bone attachments . By comparing active and passive motions that cause pain, and noting the location of the pain, the therapist gains important information about which injured tissues are involved . For example, on examination a patient is found to have limited and painful active knee flexion . this pain and limitation may be due to a lesion in the hamstring muscles (including tendons and bone attachments), the quadriceps muscles (including patella tendon and bone attachments), tibiofemoral and patellofemoral joint surfaces, meniscus, joint capsule, collateral and cruciate ligaments, or various anterior and posterior bursa. If the patient had similar pain and limitation during passive ROM, the quadriceps muscles, tibiofemoral and patellofemoral joint surfaces, meniscus, joint capsule, collateral and cruciate ligaments, or various anterior bursa may be involved . the hamstring muscles would not be implicated as these structures are put on slack and relieved of tension during passive knee flexion. Careful consideration of patient history, observation and palpation findings, and the results of additional tests and measurements such as end-feel determination , capsular versus non-capsular joint limitation patterns, accessory joint motion tests, and ligament stress tests will help to isolate the involved structures . however , passive knee flexion ROM were now normal and pain free as compared to painful during active flexion , a lesion in the hamstring muscles would be likely. the performance of resisted isometric muscle contractions would be used to confirm the presence of a lesion in the hamstring muscles . In the clinical setting, PROM is usually measured with universal goniometers or less frequently with inclinometers tape measures, and flexible rulers . With the exception of screening examinations , visual estimates are not used because they are less accurate than measurements taken with goniometers . ROM measurements of UE joints have been found to be more reliable than measurements of the LE and spine