The aim of the study was to evaluate the measurement performance of the ACTS ... test-retest reproducibility); validity (including known groups and discriminant validity); and responsiveness.

Conclusion Both versions of the new single-item measure performed as well as other short physical activity tools in terms of reliability and concurrent validity. Criterion validity testing of the ...

Despite extensive use over 40 years, physical activity questionnaires still show limited reliability and validity. Measurements have value in indicating conditions where an increase in physical ...