Comparison of heel strike accelerations while walking on carpet, tile, and a motorized treadmill

The objective of this study was to investigate the validity of utilizing treadmills in human gait studies--to investigate the correlation between heel strike data obtained while walking on a treadmill to that obtained while walking on carpet and vinyl tile. The impact data were recorded using accelerometers located in the heels of tennis and casual buck shoes. Seven male subjects were tested while walking at a normal pace on the carpeted and tiled floors and then on the treadmill at that pace. Additional gait velocities were also tested on the treadmill to study the effect of velocity on heel impact. A correlation was found between heel strike accelerations on the treadmill and the ones on the tile for both shoe types. No correlation was found for the carpet. Heel strike peak accelerations increased linearly with increasing velocity on the treadmill. Results indicate that a motorized treadmill can be utilized in gait studies as long as several factors are kept in mind: the material characteristics of the shoe, the subject's stride length, the hardness of heel impact of the subject, the subject's own walking speed, and whether the subject uses a treadmill regularly.