What term refers to abnormally increased muscle activity or movement?

The correct term that refers to abnormally increased muscle activity or movement is hyperkinesia. This condition is characterized by excessive movements, which may manifest as restlessness, excess motor activity, or involuntary movements that are more than typical.

In contrast, the other terms represent different movement disorders. Hypokinesia refers to decreased movement or reduced muscle activity, commonly seen in conditions like Parkinson's disease. Akinesia describes a complete absence of movement, which can also be a symptom of Parkinson's disease. Asthenia pertains to general weakness and a lack of energy, rather than a specific issue with motor function. Understanding these distinctions highlights why hyperkinesia is the appropriate choice for describing increased muscle activity.