Stride-to-stride variability and local dynamic stability of gait kinematics are promising measures to identify individuals at increased risk of falling. To explore their feasibility for clinical practice or ambulatory assessment, where usually short bouts of gait are available, we investigated whether multiple short bouts of gait could be used for their concurrently valid and reliable estimation. Twenty young adults walked 500m and 36 bouts of 20m wearing an accelerometer (DynaPort MiniMod) on the trunk. Within-day reliability was high for stride time variability, mediolateral trunk variability and local dynamic stability, while between-day reliability was low for both variability estimates and moderate for local dynamic stability. Stride time variability and mediolateral trunk variability were increased when walking short bouts and did not correlate well between the long and short bouts trials. Local dynamic stability did correlate highly between the long and short bouts trials, and 15 bouts of 8 strides appeared to be sufficient for valid estimation. These results imply task-specific differences and low reliability of variability estimates rendering them unsuitable for application to short bouts of gait, while local dynamic stability can be readily employed.