Comparisons of a) the absolute base of support (BOS) velocity, b) the absolute COM velocity, c) the relative COM position, d) the relative COM velocity, e) COM stability, and f) the hip height during Group B’s first (B_S1) and 16th (B_S16) slip trial and Group A’s first (A_S1) slip trial during over-ground walking. Because these measurements are taken at recovery foot liftoff approximately 150 ms after the slip onset, they are reflective of the reactive control. The first slip was completely novel to all subjects in Groups A and B, who did not know how, when or where it would occur. Group B’s B_S1 (Pre) training was therefore served as the control trial to A_S1, which took place after Group A’s treadmill training. Group B’s 16th slip trial (B_S16) was included here to assess the (Post) training effect from repeated slips induced during over-ground walking.