Publication

The effects of fatigue and age on gait dynamics.

Rocha dos Santos, P. C., Hortobagyi, T., Zijdewind, I., Gobbi, L., Barbieri, F. & Lamoth, C., 2-Jul-2019, p. 257. 258 p.

Research output: Contribution to conferencePosterAcademic

Background and Aim: Declines in gait performance in older adults are related to the dynamics features of gait (time-dependent variations in gait), such as higher gait variability and lower local dynamic stability and smoothness of the temporal patterns of walking. Some conditions could limit the availability of internal resources and perturb gait, such as those induced by fatigue. Fatigue can be expressed in terms of performance fatigability (a transient decline in the capacity to perform motor actions) and perceived fatigability (psychobiological state to manifest a lack of motivation and decline in cognitive function as a result of a prolonged period of demanding mental task). An important issue is whether or not old adults could adapt their gait dynamics to fatigue-related perturbations. Therefore, the aim of this study was to determine the effects of age and performance and perceived fatigability on dynamic metrics of gait. Methods: Twelve young and 12 older adults walked at 1.2 m/s on a treadmill before and after the two fatigue conditions on two different days. Performance fatigability was induced by repetitive sit-to-stand (STS) task until exhaustion. Perceived fatigability was induced by performing mentally demanding tasks on a computer for 30 min. Fatigue conditions were randomized between days, about a week apart. We calculated: long-range correlation (r = 1.0 as maximum) between stride time intervals using detrended fluctuations analysis (DFA); multi-scale sample entropy (MSE), in which 0 represents a complete predictability of patterns of fluctuation; the maximal Lyapunov exponent (λmax), in which larger λmax represented lower local dynamic stability. The MSE and λmax were calculated based on the Center of Pressure signals in the mediolateral (ML) and anteroposterior (AP) directions. ANOVA was used with between-factor to age and within-factors to time (pre vs. post) and fatigue conditions (STS vs. mental tasks). The effect size is reported as eta square(η²). Results: The MSE of ML decreased by 5% after mental tasks but not after STS (Time vs. fatigue conditions interaction: p < .04; η² ~ .02). Time main effect indicated significative but small increase by ~11% in λmax in ML post fatigue (p < .02; η² ~ .02). Age main effect revealed that older adults presented larger λmax in AP (~48%; p < .01; η² ~ .20) and in ML (~44%; p <.01; η² ~ .20) than young adults (p < .01 for both). Conclusion: Despite the well-documented age-related decline in gait stability, we observed minimal effects of age and performance and perceived fatigability on gait dynamics. We suspect that the treadmill makes the steps uniform, minimizing any time-related variation in the gait cycle and adaptations induced by fatigue. However, we also hypothesize that age- and fatigue-related adaptations in muscle activation underlie the uniformity of gait dynamics.
Original languageEnglish
Pages257
Number of pages258
Publication statusPublished - 2-Jul-2019
EventInternational Society for Posture and Gait Research World Congress -
Duration: 30-Jun-2019 → …

Conference

ConferenceInternational Society for Posture and Gait Research World Congress
Period30/06/2019 → …

Event

International Society for Posture and Gait Research World Congress

30/06/2019 → …

Event: Conference

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