Multifractal Nonlinearity Moderates Feedforward and Feedback Responses to Suprapostural Perturbations.

An adaptive response to unexpected perturbations requires near-term and long-term adjustments over time. We used multifractal analysis to test how nonlinear interactions across timescales might support an adaptive response following an unpredictable perturbation. We reanalyzed torque data from 44 yo...

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Publicado en:Perceptual & Motor Skills Vol. 130; no. 2; pp. 622 - 658
Autores principales: Kelty-Stephen, Damian G., Lee, Jinhyun, Cole, Keith R., Shields, Richard K., Mangalam, Madhur
Formato: Artículo
Publicado: Sage Publications Inc. Apr2023
Materias:
Acceso en línea:Ver este registro en EBSCOhost
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      dt: Apr2023
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        atl: Multifractal Nonlinearity Moderates Feedforward and Feedback Responses to Suprapostural Perturbations.
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        au:
          Kelty-Stephen, Damian G.
          Lee, Jinhyun
          Cole, Keith R.
          Shields, Richard K.
          Mangalam, Madhur
        affil:
          Department of Psychology, 14821 State University of New York at New Paltz, New Paltz, NY, USA
          Department of Physical Therapy and Rehabilitation Sciences, 573932 University of Iowa, Iowa City, IA, USA
          Department of Health, Human Function, and Rehabilitation Science, 50430 George Washington University, Washington, DC, USA
          Division of Biomechanics and Research Development, Department of Biomechanics, and Center for Research in Human Movement Variability, 14720 University of Nebraska at Omaha, Omaha, NE, USA
      su:
        Age distribution
        Task performance
        Anxiety
        Psychological adaptation
        Motor ability
        Knee physiology
        Torque
        Time
        Body movement
        Posture
        Descriptive statistics
        Research funding
      sug:
        subj:
          Age distribution
          Task performance
          Anxiety
          Psychological adaptation
          Motor ability
          Knee physiology
          Torque
          Time
          Body movement
          Posture
          Descriptive statistics
          Research funding
      keyword:
        cascade dynamics
        fractal
        perception and action
        perturbation
        rehabilitation
        cascade dynamics
        fractal
        perception and action
        perturbation
        rehabilitation
      ab: An adaptive response to unexpected perturbations requires near-term and long-term adjustments over time. We used multifractal analysis to test how nonlinear interactions across timescales might support an adaptive response following an unpredictable perturbation. We reanalyzed torque data from 44 young and 24 older adults who performed a single-leg squat task challenged by an unexpected mechanical perturbation and a secondary visual-cognitive task. We report three findings: (a) multifractal nonlinearity interacted with pre-perturbation torque production and task error to presage greater pre-voluntary feedforward increases and greater voluntary reductions, respectively, in post-perturbation task error; (b) multifractal nonlinearity presaged relatively smaller task error than standard deviations of both pre-perturbation torques and pre-perturbation task error; and (c) increased task demand (e.g., age-related changes in dexterity and dual-task settings) led to multifractal nonlinearity presaging reduced task error. All these results were consistent with our expectations, except that a pre-perturbation knee torque-dependent increase in post-perturbation task error appeared later for older than for younger participants. This correlational multifractal modeling offered theoretical clarity on the possible roles of nonlinear interactions across timescales, moderating both feedforward and feedback processes, and presaging greater stability when the standard deviation is relatively large and task demands are strong. Thus, multifractal nonlinearity usefully describes movement variability even when paired with classical descriptors like the standard deviation. We discuss potential insights from these findings for understanding suprapostural dexterity and developing rehabilitative interventions.
      pubtype: Academic Journal
      doctype: Article
      src: R
    language: English
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