Novel use of radio frequency identification (RFID) provides a valid measure of indoor stair-based physical activity

This study sought to test the validity of radio frequency identification (RFID) technology to measure indoor stair walking. RFID and Bluetooth sensors (accelerometers with the proximity function) were placed at landings across three floors within a stairwell. Participants (n = 29) were randomized to stair walking or sedentary control and concomitantly wore RFID tags at the hip, chest and neck. An accelerometer worn at the hip captured criterion physical activity data. RFID devices detected sedentary control and stair walking participants (mean RFID detections: 15.50, 47.33 respectively). Neck lanyard RFID tags were detected most frequently. RFID correctly classified all participants in both groups. RFID-based energy expenditure estimates were strongly correlated with accelerometer estimates (r = 0.78-0.94). Percent agreement for floor detection between the Bluetooth and RFID readers (38.6%) was consistent with known limitations of Bluetooth proximity sensing. It is concluded that, during self-paced stair walking in young adults, RFID devices provide valid data on participant movement and estimated energy expenditure.