Perception and Intentionality of Gait Adaptations Following Exercise-Induced Muscle Fatigue In Older Adults

Exercise-induced muscle fatigue can aject older people's gait and hence their fall risk. However, non-homogeneous gait adaptations have been shown (1), questioning whether these are caused by a direct eject of fatigue or by compensatory strategies to account for (perception of) fatigue. This study aimed to determine if older adults, when their gait changes as a result of exercise-induced muscle fatigue, perceive gait alterations, and whether these alterations are (un)intentional.

We conducted a convergent mixed-methods study with eighteen healthy older adults (>65 year, 13 females). Participants performed a paradigm of twenty repetitive sit-tostand exercises, alternated by in-between 15-m walking trails until fatigued. Gait parameters were measured using THEIA Markerless motion capture. Directly after the increasingly fatiguing walking trails, participants were interviewed on perception of gait adaptations. Gait parameters were analysed on individual level using independent samples tests. Further analysis focussed on whether older adults’ perceived gait adaptations were congruent with objective gait parameter data, and if adaptations were (un)intentional.

In most individuals, gait speed, step length, and anterior-posterior margin of stability significantly changed with exercise-induced fatigue. Participants most frequently perceived slower gait speed and decreased stability. Furthermore, only a few adaptations were intentional. Convergent analysis showed that the majority of participants did not accurately perceive the alterations in gait.

Although gait changes when fatigued, and older adults do perceive adaptations, they do not seem to congruently match their perception with actual changes. This misalignment could play a role and should be addressed in older adults’ risk for falling when fatigued.