Can Observational Training Substitute Motor Training in Preventing Backward Balance Loss following an Unexpected Slip during Walking?

A person's awareness of potential slippery walking conditions induces a cautious gait pattern. The purposes of this study were to determine whether neuromechanical changes associated with such cognitive conditioning are sufficient to alter the outcome of a slip and whether the effects of such conditioning are comparable to those of motor training. Prior to their own first slip exposure, 18 young subjects watched videos and slides demonstrating where and how the slip would occur and how people adapted to repeated-slip exposure (OBSERVE). The outcomes of the first slip exposure experienced by another 16 subjects who did not receive any such information were used as controls (NAÏVE). The latter subjects subsequently experienced an additional 23 slips and thus served in a dual-role as the motor training group (MOTOR). Gait stability as measured against backward loss of balance (BLOB) was obtained for pre-and post-slip instances. A protective step landing posterior to the slipping-limb identified each BLOB outcome. The OBSERVE group had a greater post-slip stability and lower slip displacement and velocity than the NAÏVE group. However, such effects were insufficient to prevent balance loss (100% BLOB). The MOTOR group showed significantly better performance on the last training slip (0% BLOB) than did the OBSERVE group. The results indicated that updating the cognitive centers of the CNS with awareness and perceptual knowledge through observational training can yield tangible benefits. Nonetheless, observation could not replace the task-specific motor training that adaptively updated the internal representations of stability limits for prevention of BLOB.