Detecting and quantifying global instability during a dynamic task using kinetic and kinematic gait parameters

Eytan M. Debbi*, Alon Wolf, Amir Haim

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Objectives: Instability during gait can be identified in many different ways. Recent studies have suggested utilizing spatiotemporal parameters to detect instability during gait. Detecting instability using kinetic and kinematic gait parameters has not yet been examined fully. In addition, these studies have not yet identified measures that are capable of assessing the magnitude of instability. The objective of the present study was to identify kinetic and kinematic gait parameters that can best identify instability and quantify its magnitude. Methods: Ten healthy men underwent successive gait analysis testing under three controlled settings: (1) Stage 0 instability (control setting), (2) Stage 1 instability and (3) Stage 2 instability. The levels of instability were precisely applied with the use of a controlled perturbation device (AposTherapy System). Differences between all stages and between stages were identified using Friedman and Wilcoxon tests. Results: Stride-to-stride variability (STSV) in kinetic and kinematic measures increased significantly between stages 0 and 1 or between stages 0 and 2 for almost all parameters (all P<0.05). A significant increase between stage 0 and both stages 1 and 2 was found for knee flexion moment, knee varus moment, knee flexion angle and hip adduction angle. The increase between stages 1 and 2 was variable. Only the knee varus moment parameter showed a significant increase in STSV between stages 1 and 2 (P=0.026). Conclusions: Almost all kinetic and kinematic gait parameters are sensitive to changes in global instability in a dynamic task. The most sensitive are parameters measured at the knee. Of these, STSV in knee varus moment can be used to quantify the magnitude of dynamic instability.

Original languageEnglish
Pages (from-to)1366-1371
Number of pages6
JournalJournal of Biomechanics
Volume45
Issue number8
DOIs
StatePublished - 11 May 2012
Externally publishedYes

Keywords

  • Gait analysis
  • Gait variability
  • Instability
  • Perturbation
  • Quantification of instability

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