title: Localized fatigue effects on quiet standing control by fractional Brownian motion.
abstract: In this work, the anterior-posterior displacement of the center of pressure was modeled as a fractional Brownian motion to analyze the effect of fatigue of plantar flexor muscles by isometric contraction. A sample of 17 young, healthy adults was evaluated by stabilometric test, 2 min before and after a plantar flexion, sustained until exhaustion. For each test, the model was applied to four consecutive periods of 30 s and then averaged to estimate the parameters. The fatigue increased the stochastic activity in both persistent and antipersistent controls, and also increased the Hurst exponent of the long-term mechanism. As a conclusion, the used model suggests that peripheral fatigue increases the body sway and reduces the gain of the antipersistent mechanism. However, these changes are detectable only when more than one 30 s data segment is considered for analysis.
authors.affiliation: Sport and Physical Education Department, Naval School, Brazilian Navy, Brazil. rogerfisiologia@ig.com.br
authors.forename: Roger G T
authors.initials: RG
authors.lastname: Mello
authors.forename: Liliam F
authors.initials: LF
authors.lastname: Oliveira
authors.forename: Jurandir
authors.initials: J
authors.lastname: Nadal
mesh_terms: D000328:Adult; D000465:Algorithms; D001703:Biophysics / Q000379:methods; D005221:Fatigue / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009038:Motion; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D004856:Postural Balance; D011187:Posture / Q000502:physiology; D013997:Time Factors