Validity and reliability of pedometers in habitual activity research.

In 12--18 year old boys actual steprate on a treadmill was compared to the scores of two types of mechanical pedometers (Russian and German), attached to the waist. Both types show deviations from actual steprate in running at speeds of 8 and 10 km - h-1 of ca. 5% (+/- 9%). In walking or running at 6 km - h-1 and in running at 14 km - h-1 both types give an overestimation of ca. 8.5% (+/- 8%). In walking at a speed of 2 and 4 km - h-1 the scores are not reliable because of the big standard deviation of ca. 34%. Oxygen uptake (ml - kg-1) and heart rate (beats - min-1) increase more in running than in walking, actual steprate (steps - min-1) however increases less in running compared to walking. If pedometers register only during running they reflect actual steprate fairly good and give a good estimation of the change in oxygen uptake as speed gathers.