Which term describes continuous resistance to stretching by a muscle due to abnormally increased tone?

Which term describes continuous resistance to stretching by a muscle due to abnormally increased tone?

• A. Rigidity
• B. Spasticity
• C. Dystonia
• D. Hypertrophy

Answer: (B)

Spasticity is the velocity-dependent increase in resistance to passive stretch caused by an overactive stretch reflex after an upper motor neuron injury. This means the muscle feels more resistant to being moved quickly, due to heightened neural reflexes, and is often accompanied by hyperreflexia and, at times, clonus. The key distinction is that the resistance rises with faster movement, rather than being uniform across the range. Rigid movement, by contrast, shows a constant resistance throughout the entire range and is not dependent on how fast you move the limb; that pattern is typical of rigidity seen in conditions like Parkinson’s disease. Dystonia involves sustained, abnormal muscle contractions that cause twisting or repetitive postures, not just a steady resistance to passive stretching. Hypertrophy is an increase in muscle size, not an abnormal resistance to stretch. So the term that best fits continuous resistance to stretching due to abnormally increased tone in this context is spasticity.

Spasticity is the velocity-dependent increase in resistance to passive stretch caused by an overactive stretch reflex after an upper motor neuron injury. This means the muscle feels more resistant to being moved quickly, due to heightened neural reflexes, and is often accompanied by hyperreflexia and, at times, clonus. The key distinction is that the resistance rises with faster movement, rather than being uniform across the range.

Rigid movement, by contrast, shows a constant resistance throughout the entire range and is not dependent on how fast you move the limb; that pattern is typical of rigidity seen in conditions like Parkinson’s disease. Dystonia involves sustained, abnormal muscle contractions that cause twisting or repetitive postures, not just a steady resistance to passive stretching. Hypertrophy is an increase in muscle size, not an abnormal resistance to stretch.

So the term that best fits continuous resistance to stretching due to abnormally increased tone in this context is spasticity.