Postural phase duration during self-generated and triggered gait initiation in patients with chronic ankle instability

Objective. - The neurophysiological mechanisms of chronic ankle instability (CAI) remain unclear, as evidence supports both feed-forward and feed-back neuromuscular control mechanisms. Assessing gait initiation under different conditions could provide insights into both mechanistic pathways. The primary objective of this study was to investigate changes in neuromuscular control of self-generated and triggered gait initiation in different directions in patients with chronic ankle instability. Equipment and methods. - Twenty-five CAI patients and 25 healthy volunteers participated. The participants were asked to initiate gait with maximum speed under two conditions; self generated (when they felt ready after hearing an "all set" signal) and triggered (immediately upon hearing an acoustic signal) in three different directions: straight ahead (0?), clockwise (30 degrees), and counter-clockwise (30 degrees). Duration of reaction and postural phases of gait initiation were assessed. Results. - A more prolonged reaction phase (P= 0.003) and shorter postural phase of gait ini-tiation (P= 0.012) were noted in the CAI group compared with the healthy individuals in both self-generated and triggered conditions. A shorter postural phase in the CAI group was also noted during the self-generated condition's 30 degrees counter-clockwise direction (P < 0.005). Conclusion. - Postural phase alterations in CAI patients during both self-generated and triggered gait initiation suggest that both feed-forward and feed-back neuromuscular control are altered and may present a potential neurophysiologic mechanism of CAI. (c) 2022 Elsevier Masson SAS. All rights reserved.