Susceptibility to walking balance perturbations in young adults is largely unaffected by anticipation

Emily K Eichenlaub; Daniel Duque Urrego; Sahaj Sapovadia; Jessica Allen; Vicki S Mercer; Jeremy R Crenshaw; Jason R Franz

doi:10.1016/j.humov.2023.103070

Susceptibility to walking balance perturbations in young adults is largely unaffected by anticipation

Hum Mov Sci. 2023 Jun:89:103070. doi: 10.1016/j.humov.2023.103070. Epub 2023 Mar 4.

Authors

Emily K Eichenlaub¹, Daniel Duque Urrego², Sahaj Sapovadia³, Jessica Allen⁴, Vicki S Mercer⁵, Jeremy R Crenshaw⁶, Jason R Franz⁷

Affiliations

¹ Joint Department of Biomedical Engineering, University of North Carolina Chapel Hill and North Carolina State University, Chapel Hill, NC, USA.
² Dept. of Chemical and Biomedical Engineering, West Virginia University, USA.
³ North Carolina School of Science and Mathematics, USA.
⁴ Dept. of Mechanical and Aerospace Engineering, University of Florida, USA.
⁵ Division of Physical Therapy, University of North Carolina Chapel Hill, USA.
⁶ Dept. of Kinesiology and Applied Physiology, University of Delaware, USA.
⁷ Joint Department of Biomedical Engineering, University of North Carolina Chapel Hill and North Carolina State University, Chapel Hill, NC, USA. Electronic address: jrfranz@email.unc.edu.

Abstract

Despite progress in understanding the mechanisms governing walking balance control, the number of falls in our older adult population is projected to increase. Falls prevention systems and strategies may benefit from understanding how anticipation of a balance perturbation affects the planning and execution of biomechanical responses to mitigate instability. However, the extent to which anticipation affects the proactive and reactive adjustments to perturbations has yet to be fully investigated, even in young adults. Our purpose was to investigate the effects of anticipation on susceptibility to two different mechanical balance perturbations - namely, treadmill-induced perturbations and impulsive waist-pull perturbations. Twenty young adults (mean ± standard deviation age: 22.8 ± 3.3 years) walked on a treadmill without perturbations and while responding to treadmill belt (200 ms, 6 m/s²) and waist-pull (100 ms, 6% body weight) perturbations delivered in the anterior and posterior directions. We used 3D motion capture to calculate susceptibility to perturbations during the perturbed and preceding strides via whole-body angular momentum (WBAM) and anterior-posterior margin of stability (MoS_AP). Contrary to our hypotheses, anticipation did not affect young adults' susceptibility to walking balance challenges. Conversely, perturbation direction significantly affected walking instability. We also found that susceptibility to different perturbation contexts is dependent on the outcome measure chosen. We suggest that the absence of an effect of anticipation on susceptibility to walking balance perturbations in healthy young adults is a consequence of their having high confidence in their reactive balance integrity. These data provide a pivotal benchmark for the future identification of how anticipation of a balance challenge affects proactive and reactive balance control in populations at risk of falls.

Keywords: Falls; Margin of stability; Proactive balance; Reactive balance; Whole-body angular momentum.

MeSH terms

Adult
Aged
Biomechanical Phenomena
Exercise Test
Gait* / physiology
Humans
Postural Balance* / physiology
Walking / physiology
Young Adult

Grants and funding

R21 AG067388/AG/NIA NIH HHS/United States