Gait variability in younger and older adult women is altered by overground walking protocol

SIR—Measures of gait variability are now commonly used to study age-related gait changes [1–7]. Some studies have shown that older adult fallers, and those identified with an increased falls risk, exhibit greater variability in basic spatiotemporal measures of gait when compared to both older adult non-fallers [2, 4, 5] and younger adults [4]. However, other work has reported no differences in measures of gait variability between healthy younger and older adults [6], healthy and frail older adults [7] and older adult fallers and non-fallers [1, 3]. A possible reason for the ambiguous findings of the previous studies may lie in the different walking protocols used to collect the gait data. Studies that have reported no effect of age on measures of gait variability commonly used repeated single over-ground walking protocols [1, 3, 6, 7]. Conversely, studies using continuous over-ground walking protocols have reported significant age effects [2, 4, 5, 8]. Repeated single trial walking protocols generally involve repetitive periods of waiting, gait initiation in response to an auditory command, steady-state walking for several strides, followed by gait termination at the end of a short walkway. In contrast, continuous walking protocols typically involve walking without interruption over longer distances. It is possible that the frequent disruptions to the temporal locomotor rhythm of gait experienced during repeated single walking protocols may affect gait variability and thereby contribute to the ambiguous findings reported by gait variability studies [9].