Pedometer response when riding in a vehicle: Does it count?

Studies incorporating the use of pedometers intend to count steps, but potentially respond to all ambulatory activity. Wearing a pedometer while riding in a vehicle has the potential to add substantial counts to the daily number of "steps" that are logged by the pedometer. This potential error in data collection has not been quantified. The purpose of this study was to determine the number of steps added to a pedometer worn while riding in an automobile (small sport utility vehicle). There are many confounding variables that can contribute to such error: e.g. type of pavement, type of suspension on the vehicle, kilometers (km) driven, etc. Therefore, an attempt was made to establish a representative sample of riding conditions. Fifteen subjects wore a pedometer at the waist on a belt in line with the toes of the right foot. Subjects rode in groups in a medium-sized sport utility vehicle. A 32.2-km course, approximately 50% in-town driving and 50% country driving, was followed. Total pedometer steps recorded for the 32.2-km course were 87 plus or minus 45 (Mean plus or minus Std. Dev.) "steps" [range: 28 - 156 "steps"], or 2.7 plus or minus 1.4 "steps" per km. Both values were significantly greater than zero (p