You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

(1) Background. The lockdown period due to the COVID-19 pandemic has drastically decreased levels of physical activity in the population. Hemophilia is characterized by hemarthrosis that leads to chronic, progressive and degenerative joint deterioration. (2) Methods. This observational study recruited 27 patients with hemophilia and arthropathy. Knee, ankle and elbow joints were assessed. The frequency of clinical hemarthrosis, pain intensity, pressure pain threshold, and joint ROM were evaluated. (3) Results. Following lockdown, a significant deterioration of joint condition, perceived joint pain and range of motion was noted in all joints. There were no changes in the frequency of knee hemarthrosis, while the frequency of ankle hemarthrosis significantly reduced. However, the frequency of elbow hemarthrosis increased. Depending on the degree of hemophilia severity, there were changes in pressure pain threshold in the elbow and in pain intensity and range of motion of the ankle joint. According to the type of treatment, i.e., prophylaxis vs. on-demand treatment, there were differences in the joint condition in elbows and the plantar flexion movement of the ankle. There were no differences in the knee joint based on the severity of the disease, the type of treatment or the development of inhibitors (4). Conclusions. Because of the COVID-19 lockdown, the musculoskeletal status of patients with hemophilia deteriorated. Joint condition, perceived pain, and range of motion were significantly affected. The frequency of clinical hemarthrosis did not increase during this period. A more active therapeutic model could prevent rapid deterioration in patients with hemophilic arthropathy during prolonged sedentary periods.
["Prevention"]