Evaluation of an ankle–foot orthosis effect on gait transitional stability during ramp ascent/descent

Gait dynamic stability evaluation in patients undergoing hip joint fractures – tools to measure rehabilitation effectiveness

“…The CoP waveforms have been used earlier to evaluate gait stability during weight-loading and unloading transitions [9,14,27]. Following that, the CoP raw data was extracted from the GaitRec repository both in anterior-posterior (AP) and medial-lateral (ML) directions.…”

“…A lower-order filter was selected to avoid unnecessary time delays and over-smoothening that can diminish the difference between fractured and normal waveforms. Similar filter specs were also used earlier for cleaning CoP-velocity signals [14,27,32]. The rate-of-change (derivative) of CoP signals was computed and thereafter averaging algorithm was applied to reduce the derivative-induced noise following prior studies [9,14,27].…”

“…Similar filter specs were also used earlier for cleaning CoP-velocity signals [14,27,32]. The rate-of-change (derivative) of CoP signals was computed and thereafter averaging algorithm was applied to reduce the derivative-induced noise following prior studies [9,14,27]. The average CoP-velocity illustrated two characteristic impulses: one major impulse at the start and the other minor impulse at the end of the waveforms as shown in figure 2.…”

“…Here, the time series CoP-velocity waveforms illustrated artefacts in the data due to variations in subjects' anthropometry, lack of repeatability of trials, and adaptability to the experimental conditions. Thus, the data arranged for each variant was cleaned from artefacts by applying Principal Component Analysis (PCA); a computational tool used previously for data cleaning and linearization [14,27,28]. PCA was implemented independently for the loading and unloading phases in all variants.…”

“…Gait dynamic stability assessment methods are broadly categorised into three ways: (1) the Lyapunov exponent [19,20] and variability analysis [21,22] methods use whole gait cycle data to compute the stability metrics; (2) the margin of stability computes body's centre of mass (CoM) difference from the base of support at discrete gait events (heel contact and toeoff) [21,[23][24][25]; (3) Nyquist and Bode (N&B) methods compute critical stability margins within a sub-phase of a gait cycle [9,14,[26][27][28][29]. Among these reported techniques, stability assessment using whole gait cycle waveforms or at discrete gait events has obvious limitations of stability evaluation during gait inner phases such as weight loading and unloading.…”