Intra-Rater Reliability and Concurrent Validity of the 2-minute Step Test applied virtually to Healthy Adults: a Descriptive Study

Abstract

Background: Morbidity of cardiopulmonary diseases is heavily affected by cardiopulmonary fitness (CPF), which is correlated with physical activity and inversely correlated with all-case mortality. People with cardiopulmonary disorders often have lower CPF, due to pathological changes causing pulmonary symptoms, such as exercise intolerance. Assessment of CPF, before, during and after prescribed rehabilitation programmes is an important role of physiotherapists. This is often achieved by exercise testing using, for example, the 2-minute step test (2MST). 2MST is valid and reliable when conducted in person. In conditions such as those imposed by the COVID-19 pandemic, teleassessment can help physiotherapists to continue to monitor CPF remotely, therefore, the reliability and validity of 2MST conducted remotely, currently unknown, is important. Study aims: To determine intra-rater reliability and concurrent validity of remotely administered 2MST in healthy people. Methods: an observational study comprising three remotely administered 2MST separated by 15-minute rest intervals, followed, within a week, by a face-to-face 2MST. Remote 2MSTs were supervised by the researcher via a web-based videoconferencing tool. Achieved steps were used to estimate reliability. Scores from the second remote and face-to-face assessments were used to assess validity. Results: In a sample of ten healthy participants, eight males, mean age 25.6 (22 – 30) years, intra-rater reliability of remote 2MST was excellent (ICC = 0.924), and there was strong correlation between remote and face-to-face tests (Pearson’s r = 0.865; p < 0.01). Agreement between remote and face-to-face tests was relatively low (mean difference -1.8 steps) with wide limits of agreement (-17.92 – 14.32). Conclusions: The findings suggest that 2MST administered remotely, when used on healthy adults, with excellent relative reliability and high levels of validity. However, due to lower absolute agreement between the tests cannot be used interchangeably. further studies could overcome the limitations of this study and confirm its legitimacy.