Effect of body composition on the validity and reliability of an electronic pedometer

This paper examines the effect of body composition and pedometer position on the validity and reliability of a pedometer. 52 adults (24F, 28M, BMI range 21-52kg/m) participated. Body composition was measured by BMI, waist to hip ratio and percentage body fat and categorised as: 1.) normal, 2.) overweight, 3.) obese I, and 4.) obese II (BMI only). Participants wore 4 pedometers (front (2), side and back) on their right side at waist level. Participants completed a 40 metre walking course at a slow, moderate and brisk walk on two occasions. Pedometer steps were compared to steps recorded by direct observation. For normal weight participants no differences were found between observed and pedometer steps (p>0.01). Among overweight participants, there was a difference (p<0.01) between observed and pedometer steps during slow walking in the back position. Obese I and II participants had differences (p<0.01) between observed and pedometer steps during slow (and moderate for obese I) walking in the side position. No differences were found between pedometer steps recorded during test 1 and 2. In conclusion, no significant differences were found across all body compositions, and for all walking speeds, between observed and pedometer-measured steps when the pedometer was worn in the front position.