Learning to suppress a balance recovery step: implications for improving behavioral flexibility in a balance recovery stepping task

Background
Research shows compensatory balance responses can be improved with training. The present study is a coincidental finding from a registered report that provides insight into trainability of response inhibition in a balance recovery stepping task.

Research question
Can suppression of response inhibition in a rapid balance recovery step be improved with training?

Methods
Young, healthy participants (N = 20) were released from a supported, forward lean to prompt a rapid balance recovery step. In most trials, participants were instructed to recover balance by quickly stepping forward (i.e., GO trials). However, in 20 % of the trials, a high-pitch tone was randomly played immediately after postural perturbation, signaling participants to suppress a step and relax into a catch harness (i.e., STOP). This balance recovery task was repeated on two separate days. Force plates measured GO reaction time post-perturbation and stepping errors on STOP trials.

Results
Task performance improved on the second day of testing, including faster steps (321 ± 37 ms vs. 348 ± 40 ms; p < 0.001) and more successful inhibition (46 ± 19% vs. 36 ± 19%; p = 0.005). Also, stop signal reaction time was faster on day two (286 ± 41 ms vs. 308 ± 46 ms; p = 0.041), suggesting the cognitive ability to suppress a highly prepotent action was directly influenced.

Significance
Our results build from past studies where balance reactions improve with practice and we now demonstrate that outright action cancellation within a balance recovery stepping task can be trained, suggesting behavioral flexibility can be improved without compromising response speed.