acceleration RMS of body COM (normalized by gait velocity)
in ML direction (P=0.038), while no difference was found
between these two groups (P=0.336). (Fig.2)
In AP direction, middle-aged adults (0.562 1/s) and young
(0.534 1/s) had a lower value of acceleration RMS than older
ones (0.695; P=0.024)