A muscle that is weak, not being recruited as it should is described as which term?

• A. Repetitive lack of motion
• B. Underactive
• C. Overactive
• D. Kyphosis

Answer: (B)

The main idea is how actively a muscle is working during movement. A muscle that is weak and not being recruited as it should doesn’t fire enough when you perform a task—that’s described as underactive. When a muscle is underactive, it fails to contribute its share of force and control, leading to compensations by other muscles and altered movement patterns. In practice, identifying underactive muscles guides activation strategies: you design exercises to turn those muscles back on so they can help stabilize joints and improve technique, while often addressing any overactive muscles that may be taking over.

For example, if the glutes are underactive during a squat, the hips may not extend effectively and the quadriceps or lower back could take over, creating imbalances. You’d use targeted activation drills to wake up the glutes and restore proper hip function. In contrast, overactive describes muscles that are too tense or frequently over-engaged, which is the opposite situation. Kyphosis is a spinal posture condition, not a description of a muscle’s activity level, and “repetitive lack of motion” isn’t a standard term for a muscle’s recruitment.