Biomechanics- Test Positioning

When measuring for range of motion (ROM) it is important that one know the proper bony landmarks used for the goniometer and proper positioning of the patient. ROM is used to tell us the amount of motion available in a joint in degrees. First, in order for the test to be reliable and as accurate as possible you must palpate bony landmarks and use the same position each time. Locating these bony landmarks also tells the therapist things like tissue irregularities and the presence or absence of muscle contractions. Patient position is important so that we know they are moving in a way that allows them to get the full ROM possible for that joint. Proper positioning will also help expose any hyper or hypo mobility of the joints or substitute movements. In manual muscle testing (MMT) the therapist will help the clients in to test position of the patient (so if they are supine, prone, etc.) and test position of the limb (flexed, extended, etc.). Optimal test position of the limb is in midrange of the joint because this is where the most cross-bridges in the muscles are formed, and therefore allowing for maximum muscle strength. The purpose of patient position is to allow for the most and safest amount of muscle contraction. Using the proper positioning also keeps the data reliable and accurate. Having the same therapist (intrarater) is the most reliable, but data should be taken and recorded in a way that a different therapist could measure in the exact same way. This is why it is important to know these positioning. A gravity eliminated position should be used if the patient is too weak. Most movements are in the opposite position of gravity so gravity is acting as an extra resistance on the muscle. Eliminating that resistance will allow weaker muscles to exert more force and have a more optimum contraction, giving a better measurement in those weaker muscles.