Protective nervous system tone, contracture, guarding of muscle describes which concept?

• A. Mobility
• B. Passive tension
• C. Active tension
• D. Flexibility

Answer: (C)

The idea being tested is how muscle force in guarding or protective posturing comes from the muscle actively contracting. When the body detects potential injury or threat, the nervous system increases motor drive to the surrounding muscles, causing them to shorten and stiffen to protect the area. That active contraction generates active tension—the force produced by muscle fibers during activation—rather than relying on passive stretch or tissue elasticity.

Passive tension would be the resistance you feel when a muscle is stretched without activating it, coming from non-contractile tissues. Flexibility and mobility describe range of movement, but guarding and a protective tone reflect the muscle’s active contraction to stabilize, not just the passive properties of the tissue.