Validity and reliability of an inertial device (WIMU PRO™) to quantify physical activity level through steps measurement

BACKGROUND: Currently, there is an increase in the application of accelerometers to quantify physical activity level through daily steps, and therefore, it is required that the devices are valid and reliable. The current study tested the validity of the WIMU PROTM inertial device in steps detection and the inter-device reliability for steps measurement. METHODS: Ten endurance-trained men volunteered to participate in this study (height: 1.78 +/- 0.05 m; body mass: 72.96 +/- 4.2 kg). Twelve trials of 40.32 m at different speeds (four trials at each speed) were performed: 1) walking (< 5 km/h); 2) jogging (5-10 km/h) and running (10-15 km/h). The video analysis was used as criterion to assess validity, while, two WIMU PROTM inertial devices were compared to assess betweenunit reliability. RESULTS: A near-perfect validity between video analysis and WIMU PRO (TM) (ICC=0.999; bias=0.03) and a very good reliability between WIMU PROTM devices (bias=-0.01; CV=0.02%) was found. The highest values were found at walking (ICC=0.999) and the lowest values were found at running (ICC=0.995). CONCLUSIONS: WIMU PROTM is a reliable and valid device to quantify physical activity level through steps measurement.