The effect of walking speed on quality of gait in older adults

•Measured 3D trunk accelerations while older adults walked at four treadmill speeds.•Estimated gait quality characteristics to elucidate the effect of speed.•All gait characteristics were affected by speed, except AP sample entropy.•Higher speed led to qualitatively better gait for most characteristics.•Speed may underlie differences in gait quality among older fallers and non-fallers. Gait quality characteristics can contribute to the identification of individuals at risk of falls. Since older adults with high fall risk tend to walk slower than older adults with a lower fall risk, walking speed may underlie differences in gait quality characteristics. How does walking speed affect gait quality characteristics in older people? We investigated the effect of walking speed on gait characteristics in 11 older adults (aged 69.6 ± 4.1 years). Trunk accelerations (Dynaport MoveMonitor) were recorded during 5 min of treadmill walking at four different speeds. From these trunk accelerations we calculated step frequency, root mean square, harmonic ratio, index of harmonicity, sample entropy and logarithmic divergence rate per stride. Our results showed that all gait characteristics were affected by walking speed, except for sample entropy in antero-posterior (AP) direction. An increase in walking speed resulted in a higher step frequency, higher standard deviation, more symmetric gait, more smooth vertical (VT) accelerations, less smooth accelerations in medio-lateral (ML) and AP directions, less regular dynamics in ML direction, more regular dynamics in VT direction, and a more stable gait pattern overall. These findings suggest that, within a range of 0.5–1.4 m/s, a lower walking speed results in a lower gait quality, which may underlie differences in gait quality between older fallers and non-fallers.