Comparison of temporal aspects of overground and treadmill walkings

There have been a lot of arguments concerning similarity in temporal aspect between overground (OG) and treadmill (TM) walkings. As TM walking is used as a valid simulator both in clinical exercise and assessment, equivalency in temporal aspect between them is important. We compared temporal factors of OG and TM walkings at the same velocity, using foot switches. Ten healthy subjects were instructed to walk OG and on a TM at 2 different speeds; what they considered comfortable and fast when walking OG. Mean velocities were 5.2 km/h and 6.7 km/h. TM walking presented significantly shorter stride time than OG walking, which was consistent with the results of other studies. Though some researchers have reported differences between them, both walkings presented exactly identical ratios of stance and swing times. There was equivalence between the two walking styles from the viewpoint of relative timing.