Article

To our knowledge, the effect of instructions limiting the number of steps on the
threshold of balance recovery has not been quantified, which could make
comparisons between studies difficult. We determined the maximum forward lean
angles from which 28 younger adults could be suddenly released and still recover
balance using: (i) only a single step, (ii) no more than two steps and (iii) no
limit on the number of steps. Results showed that instructions limiting the
number of steps significantly affected the maximum lean angle but only by a
maximum of 1 degree. At the maximum lean angles, they also significantly affected
reaction time, first weight transfer time, first stride velocity, first stride
length and second stride velocity but only by 8% on average. However, they did
not affect muscular latencies, first stride time, first stride height, first
stride width or other second step variables. Moreover, at lean angles larger than
their maximum, participants were able to respect the instructions but unable to
recover balance without safety harness assistance. Given that the effect was too
small to be pertinent, we can state that, between the three limits on the number
of steps, not only were the maximum lean angles similar but the first steps were
nearly identical and the additional steps did not help to increase the maximum
lean angle. Therefore, we have demonstrated that instructions limiting or not
limiting the number of steps appear to be equally valid to study the threshold of
balance recovery in younger adults.

Langue : ANGLAIS