Reliability (Test-retest) of 30 Seconds Sit-to-stand and Timed Up and Go in Adults With Long Covid

Since December 2019, Covid-19 has affected millions of people worldwide, leaving many of them with symptoms such as fatigue, (muscle) weakness and dyspnoea, even months after their infection (long covid). Rehabilitation centers were established to aid this new group of patients. This study's aim is to test the reliability of 2 outcome measures for patients with long covid. 30 seconds Sit-To-Stand and Timed Up And Go tests are not specific to a disease but they evaluate functionality, mobility and endurance. They are easy to perform in a clinical setting as they do not require specific equipment. The reliability of the above tests has yet to be established in people with long covid.

A sample size of 19 people will be used. A difference in reliability of 0.9 and 0.7 at 80% power and a 5% level of significance using two ratings was set. Based on two testing sessions, an x value of 0.05, and a power of 0.80, a minimal sample size of 19 patients was identified (Karagiannis et al., 2020).

19 patients with long covid from the rehabilitation center will take both tests in a single day and 3 days later they will take the tests again with no physical therapy intervention in between the measurements.

For the statistical analysis, ICC (Intra-class correlation coefficients), SEM (standard error of measurement) and Bland-Altman plot will be used. These tests evaluate test-retest reliability, through the identification of the agreement of patient's scores between the 2 measurements and they evaluate the measurement precision (Savva et al, 2014).

Inclusion criteria

• Adults who were infected with COVID-19 virus in the last 6 months and were diagnosed with long-covid
• Patients must be willing to give written consent for participation in the study
• Negative rapid test for COVID-19

Exclusion criteria

• People under 18 years of age
• Significant cognitive and psychiatric impairments (inability to follow simple commands or give consent)
• Refuse to give consent