Accuracy of a Pedometer and an Accelerometer in Women with Obesity

Aim: The main purpose of this study was to examine the accuracy of a specific pedometer (Silva model Pedometer Plus 56013-3) and accelerometer (Silva model Ex3 plus 56026) in women suffering from obesity. The second aim was to study the impact of BMI, waist and hip circumference and waist-hip ratio on different pedometer and accelerometer positions on the body. Methods: Forty women with a BMI > 30 kg/m wore two pedometers and two accelerometers during a standardized 6 minute walk test. Accelerometer 1 (A1) was placed around the neck. Accelerometer 2 (A2) was attached to the waistband of the woman’s trousers in line with left hip, Pedometer 1 (P1) in line with right hip and pedometer 2 (P2) behind back in line with the spine. During the test an assistant manually counted number of steps, using a hand counter as reference for step accuracy. Results: Steps registered with the pedometer were significantly different from actual steps counted. The intra class correlations for the actual steps counted compared with the steps registered were P1 = 0.13, P2 = 0.20, A1= 0.99 and A2 = 0.41. All correlations between the tested pedometer and accelerometer at the different locations and BMI, waist circumference, hip circumference and hip-to waist ratio were little (if any) or low. Conclusions: The accelerometer is more accurate than the pedometer in measuring steps in women suffering from obesity. The location, which gave the most accurate results, was found to be around the neck.