Effect of initial foot position on postural responses to lateral perturbations during standing in younger and older adults

Maintaining balance stability while turning in a quasi-static stance and/or in dynamic motion requires proper recovery mechanisms to manage sudden center-of-mass displacement. Furthermore, falls during turning are among the main concerns of community-dwelling elderly population. This study investigates the effect of aging on reactive postural responses to continuous yaw perturbations on a cohort of 10 young adults (mean age 28 ± 3 years old) and 10 older adults (mean age 61 ± 4 years old). Subjects underwent external continuous yaw perturbations provided by the RotoBit1D platform. Different conditions of visual feedback (eyes opened and eyes closed) and perturbation intensity, i.e., sinusoidal rotations on the horizontal plane at different frequencies (0.2 Hz and 0.3 Hz), were applied. Kinematics of axial body segments was gathered using three inertial measurement units. In order to measure reactive postural responses, we measured body-absolute and joint absolute rotations, center-of-mass displacement, body sway, and inter-joint coordination. Older adults showed significant reduction in horizontal rotations of body segments and joints, as well as in center-of-mass displacement. Furthermore, older adults manifested a greater variability in reactive postural responses than younger adults. The abnormal reactive postural responses observed in older adults might contribute to the well-known age-related difficulty in dealing with balance control during turning.

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Postural Responses to a Suddenly Released Pulling Force in Older Adults with Chronic Low Back Pain: An Experimental Study

PLoS ONE ◽

10.1371/journal.pone.0162187 ◽

2016 ◽

Vol 11 (9) ◽

pp. e0162187 ◽

Cited By ~ 2

Author(s):

Pei-Yun Lee ◽

Sang-I Lin ◽

Yu-Ting Liao ◽

Ruey-Mo Lin ◽

Che-Chia Hsu ◽

...

Keyword(s):

Older Adults ◽

Experimental Study ◽

Low Back Pain ◽

Back Pain ◽

Chronic Low Back Pain ◽

Low Back ◽

Postural Responses ◽

Pulling Force

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Inefficient Postural Responses to Unexpected Slips During Walking in Older Adults

The Journals of Gerontology Series A ◽

10.1093/gerona/53a.6.m471 ◽

1998 ◽

Vol 53A (6) ◽

pp. M471-M480 ◽

Cited By ~ 135

Author(s):

P.-F. Tang ◽

M. H. Woollacott

Keyword(s):

Older Adults ◽

Postural Responses

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Different visual manipulations have similar effects on quasi-static and dynamic balance responses of young and older people

PeerJ ◽

10.7717/peerj.11221 ◽

2021 ◽

Vol 9 ◽

pp. e11221

Author(s):

Daniel Schmidt ◽

Felipe P. Carpes ◽

Thomas L. Milani ◽

Andresa M.C. Germano

Keyword(s):

Older Adults ◽

Balance Control ◽

Dynamic Balance ◽

Visual Deprivation ◽

Elderly Persons ◽

Eyes Closed ◽

Balance Tests ◽

Postural Responses ◽

Eyes Open ◽

Visual Conditions

Background Studies demonstrated that the older adults can be more susceptible to balance instability after acute visual manipulation. There are different manipulation approaches used to investigate the importance of visual inputs on balance, e.g., eyes closed and blackout glasses. However, there is evidence that eyes open versus eyes closed results in a different organization of human brain functional networks. It is, however, unclear how different visual manipulations affect balance, and whether such effects differ between young and elderly persons. Therefore, this study aimed to determine whether different visual manipulation approaches affect quasi-static and dynamic balance responses differently, and to investigate whether balance responses of young and older adults are affected differently by these various visual conditions. Methods Thirty-six healthy participants (20 young and 16 older adults) performed balance tests (quasi-static and unexpected perturbations) under four visual conditions: Eyes Open, Eyes Closed, Blackout Glasses, and Dark Room. Center of pressure (CoP) and muscle activation (EMG) were quantified. Results As expected, visual deprivation resulted in larger CoP excursions and higher muscle activations during balance tests for all participants. Surprisingly, the visual manipulation approach did not influence balance control in either group. Furthermore, quasi-static and dynamic balance control did not differ between young or older adults. The visual system plays an important role in balance control, however, similarly for both young and older adults. Different visual deprivation approaches did not influence balance results, meaning our results are comparable between participants of different ages. Further studies should investigate whether a critical illumination level may elicit different postural responses between young and older adults.

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Aging changes in protective balance and startle responses to sudden drop perturbations

Journal of Neurophysiology ◽

10.1152/jn.00431.2018 ◽

2019 ◽

Vol 122 (1) ◽

pp. 39-50 ◽

Cited By ~ 6

Author(s):

Ozell Sanders ◽

Hao Yuan Hsiao ◽

Douglas N. Savin ◽

Robert A. Creath ◽

Mark W. Rogers

Keyword(s):

Older Adults ◽

Impact Force ◽

Medial Gastrocnemius ◽

Whole Body ◽

Electromyographic Activity ◽

Younger Adults ◽

Sudden Drop ◽

Postural Responses ◽

Landing Impact ◽

Associated Abnormalities

This study investigated aging changes in protective balance and startle responses to sudden drop perturbations and their effect on landing impact forces (vertical ground reaction forces, vGRF) and balance stability. Twelve healthy older (6 men; mean age = 72.5 ± 2.32 yr, mean ± SE) and 12 younger adults (7 men; mean age = 28.09 ± 1.03 yr) stood atop a moveable platform and received externally triggered drop perturbations of the support surface. Electromyographic activity was recorded bilaterally over the sternocleidomastoid (SCM), middle deltoid, biceps brachii, vastus lateralis (VL), biceps femoris (BF), medial gastrocnemius (MG), and tibialis anterior (TA). Whole body kinematics were recorded with motion analysis. Stability in the anteroposterior direction was quantified using the margin of stability (MoS). Incidence of early onset of bilateral SCM activation within 120 ms after drop onset was present during the first-trial response (FTR) for all participants. Co-contraction indexes during FTRs between VL and BF as well as TA and MG were significantly greater in the older group (VL/BF by 26%, P < 0.05; TA/MG by 37%, P < 0.05). Reduced shoulder abduction between FTR and last-trial responses, indicative of habituation, was present across both groups. Significant age-related differences in landing strategy were present between groups, because older adults had greater trunk flexion ( P < 0.05) and less knee flexion ( P < 0.05) that resulted in greater peak vGRFs and decreased MoS compared with younger adults. These findings suggest age-associated abnormalities of delayed, exaggerated, and poorly habituated startle/postural FTRs are linked with greater landing impact force and diminished balance stabilization. NEW & NOTEWORTHY This study investigated the role of startle as a pathophysiological mechanism contributing to balance impairment in aging. We measured neuromotor responses as younger and older adults stood on a platform that dropped unexpectedly. Group differences in landing strategies indicated age-associated abnormalities of delayed, exaggerated, and poorly habituated startle/postural responses linked with a higher magnitude of impact force and decreased balance stabilization. The findings have implications for determining mechanisms contributing to falls and related injuries.

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