Which of the following best describes a step in performing an MMT?

• A. Stabilize the proximal segment; apply resistance to the distal segment; apply resistance in line with the muscle orientation; watch for substitution or compensation by other muscles
• B. Stabilize the distal segment; apply resistance to the proximal segment; apply resistance in line with the muscle orientation; watch for substitution or compensation by other muscles
• C. Stabilize the proximal segment; apply resistance to the distal segment; apply resistance opposite to the muscle orientation; watch for substitution
• D. Stabilize the proximal segment only; apply resistance to the distal segment; avoid watching for substitutions

Answer: (A)

In manual muscle testing, isolating the target muscle is essential so you measure its true strength. That begins with stabilizing the proximal segment to prevent movement at the joint closest to the body, which keeps the test focused on the intended muscle rather than accessory muscles. You then apply resistance to the distal segment, directing that force along the muscle’s line of pull so the muscle fights a load in its natural vector. While doing this, you watch for substitutions or compensations by other muscles, because these indicate the test isn’t isolating the targeted muscle or that the technique needs adjustment. This combination—proximal stabilization, distal resistance in line with the muscle orientation, and vigilant observation for substitutions—best reflects a proper step in performing an MMT.

Stabilizing the distal segment or applying resistance to the proximal segment would not isolate the muscle tested. Applying resistance opposite to the muscle’s orientation would alter the test vector and recruit different muscles. And you should always monitor for substitutions rather than avoid doing so.