The inability to hop in place on each foot is most suggestive of which dysfunction?

The inability to hop in place on each foot is most suggestive of which dysfunction?

• A. cerebellar dysfunction
• B. corticospinal tract weakness
• C. proximal tract weakness
• D. weakness of the quadriceps

Answer: (A)

Coordinated, precise timing of muscle activation and dynamic balance are governed by the cerebellum. Hopping in place on a single foot requires rapid, coordinated movement with continual adjustments to maintain balance and posture. When cerebellar function is impaired, this kind of task becomes unreliable because the brain can’t fine-tune the sequencing and timing of muscle contractions in real time, leading to ataxia-like clumsiness and an inability to hop smoothly. If the issue were corticospinal tract weakness, you’d expect a primary loss of strength or weakness-dominant findings in the leg, not a coordination failure. Proximal muscle weakness would mainly show up as difficulty with movements powered by large proximal muscles, rather than a disruption of the delicate timing needed to hop. Quadriceps weakness would specifically hamper knee extension strength, making hopping mechanically hard, but that’s a strength problem rather than a coordination/problem with timing and balance.

Coordinated, precise timing of muscle activation and dynamic balance are governed by the cerebellum. Hopping in place on a single foot requires rapid, coordinated movement with continual adjustments to maintain balance and posture. When cerebellar function is impaired, this kind of task becomes unreliable because the brain can’t fine-tune the sequencing and timing of muscle contractions in real time, leading to ataxia-like clumsiness and an inability to hop smoothly.

If the issue were corticospinal tract weakness, you’d expect a primary loss of strength or weakness-dominant findings in the leg, not a coordination failure. Proximal muscle weakness would mainly show up as difficulty with movements powered by large proximal muscles, rather than a disruption of the delicate timing needed to hop. Quadriceps weakness would specifically hamper knee extension strength, making hopping mechanically hard, but that’s a strength problem rather than a coordination/problem with timing and balance.