Which term describes the baseline tension present in resting muscles?

• A. Muscle tone
• B. Hypertonia
• C. Hypertrophy
• D. Hypotonia

Answer: (A)

Baseline tension present in resting muscles is muscle tone. It’s the normal level of contractile activity that keeps muscles ready and helps maintain posture even when you’re not actively contracting. This background tension comes from ongoing motor neuron input to the muscle and feedback from muscle spindles, creating a slight resistance to passive movement that keeps the limb positioned appropriately.

In clinical terms, this tone can vary within the normal range, but when it’s abnormally high, it’s described as hypertonia—often due to upper motor neuron injuries that heighten reflexes and resistance. When tone is reduced, it’s called hypotonia, resulting in a floppier, less stable muscle feel. Hypertrophy, on the other hand, refers to an increase in muscle size from training or growth, not to the level of resting tension.