Abstract

The measurement of everyday physical activity by accelerometry has gained in recent years a large role in the medical, sports and psychology science research. The purpose of this study was to validate the accuracy of the Move II (movisens GmbH, Karlsruhe, Germany) activity sensor for measuring steps during different everyday life walking activities and compare it with GT3X (ActiGraph Manufacturing Technology Inc., FL, USA), a widely used activity monitor. Eight females (30.8 ± 8.6 yrs.) and 11 males (30.2 ± 9.0 yrs.) (Mean ± SD) ranging in BMI from 19.43 to 33.31 kg·m-2 were equipped with the Move II as well as the GT3X activity sensor and where asked to perform different everyday life walking activities. An ankle-mounted acceleration sensor which delivers raw data was used as reference for the manual annotation of steps during the free-living environment activities. Move II revealed a high accuracy in counting steps with a mean percent error of 0.6 ± 1.1 % for all the activities. GT3X displayed a mean percent error of 4.7 ± 3.7 %. The least accurate results for both devices were observed during stair walking; 1.8 ± 3.2 % and 13.7 ± 10.4 % for Move II and GT3X respectively. The greatest accuracy for both Move II and GT3X was found during walking fast; 0.0 ± 0.1 % and 0.0 ± 0.2 % of errors respectively. Our data suggest that both devices are appropriate for measuring step counts in everyday life. Verf.-Referat