Fig. 13.

Example of a participant decelerating COM movement with a sudden movement of the nonstance leg. The COM can be seen to start moving towards the right (positive) side after ∼3 s in the trial, coinciding with gradual tilting of the balance board (A). After 6 s in the trial the COM is decelerated, as reflected in a negative peak in the COM acceleration (B). This peak is the result of a left, nonstance leg movement initiated after ∼6 s as illustrated in C and D, which shows the orientation of the segments after subtraction of their mean values. This movement gives rise to the negative angular momentum of the free leg (E and F), which causes the negative acceleration of the COM that limits further right COM movement.