ROM and MMT-Biomechanics (2)

When measuring Range of Motion (ROM), it is important to palpate bony landmarks and use proper positioning. The bony landmarks serve as a reference point for where the therapist should place the goniometer in order to have good accuracy and reliability. The goniometer has three parts: the stationary arm, the moving arm, and the axis. If the therapist changes the reference point, the values will neither be accurate nor reliable. For example: when measuring ROM for elbow flexion, the axis/fulcrum of the goniometer is placed on the lateral epicondyle, the stationary arm is placed on the lateral midline of the humerus in line with the acromion process, and the moving arm is placed on the lateral midline of the radius in line with the radial styloid process. If the therapist didn't palpate before placing the goniometer the first time measuring ROM for the patient, the measurements would be off. The next time she measured Range of motion, the numbers would not be consistent. This example shows how not palpating bony landmarks affects accuracy and intra-rater reliability.  While intra-rater reliability is higher than interrater reliability for measuring ROM, not using bony landmarks as a point of reference would affect both. In the same way, the proper positioning of the patient's body is needed for the measurements to be consistent and accurate.  In different positions, the ROM will show different measurements due to the relaxing and tightening of different muscle groups in different positions. If the patient is not placed in the proper position, they also may be at a mechanical disadvantage. Inaccurate and unreliable results would affect paperwork, billing, and insurance claims. They could also put the patient in danger if the patient is given the wrong therapy treatments based on the results.



Manual Muscle Testing (MMT)  is used to evaluate a patient's muscle(s) strength/function. When using MMT, it is important that the patient is placed in the proper test position so that the right muscles are activated during the test. It is also important so that the patient is at a mechanical advantage and can produce the most force possible from the specific isolated muscle or muscle groups. Usually, MMT is completed in against gravity position. However, in certain circumstances, the patient may need to be placed in a gravity-eliminated position. This is a resistant-free position and means that the force of gravity is no longer contributing to the resistance placed on that muscle/muscle group.  In this position, the patient's body is placed so that their action is parallel to the ground and the therapist is not applying resistance. The therapist uses a gravity-eliminated position when muscles are weaker and are unable to withstand the resistance of the four second MMT in an against gravity position with or without resistance from the therapist. The scoring for a gravity-eliminated position is less than 2+ according to the MMT grading chart. If there is almost no Range of Motion but the therapist can sense a small contraction from feeling the muscle, the patient score will be a  1 on the MMT grading scale. If there is no palpable or observable muscle contraction, the patient score will be 0.

Picture from: https://www.scranton.edu/faculty/kosmahl/courses/gonio/upper/pages/elbow-flex.shtml