Effects of age and gender on dynamic stability during stair descent.
OBJECTIVE
To determine the effects of age and sex and their interaction effects on dynamic postural stability during stair descent.


METHODS
Cross sectional.


METHODS
Laboratory.


METHODS
Healthy younger adults (N=28) and healthy older adults (N=21).


METHODS
Not applicable.


METHODS
Spatiotemporal gait parameters, displacement of center of mass (COM), instantaneous velocity of the COM, divergence between vertical projection of the COM, and center of pressure (COP).


RESULTS
Interaction effects of age and sex were found in stride duration, COM displacement, and instantaneous velocity of the COM in the mediolateral direction. Older adults demonstrated longer stride duration with shorter double-limb stance and longer single-limb stance during stair descent. Women have significantly longer stride duration than men. The effects of sex and age were significant in the data normalized by height. Older adults and women demonstrated larger peak-to-peak COM displacement, peak instantaneous velocity of the COM, and COM-COP divergence than the younger individuals and men, respectively. Peak instantaneous velocity of the COM was significant different in most pairwise comparisons, but the COM-COP divergence was significantly different in several comparisons.


CONCLUSIONS
This study examined the COM and COP parameters to quantify dynamic stability during stair descent across sex and age. Although older women descended stairs successfully, they demonstrated differences in control of instantaneous velocity of the COM compared with the other participants. Dynamic instability could be detected by examining the control of instantaneous velocity of the COM. In developing a better understanding of the balance control of stair descent in healthy older adults, aging patients with various pathologies can be better assessed, appropriately treated, and provided with proper assistive devices.
Department of Physical Therapy, National Cheng Kung University, Tainan, Taiwan.
Bih-Jen
BJ
Hsue
Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan; Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan. Electronic address: fcsu@mail.ncku.edu.tw.
Fong-Chin
FC
Su
D000328:Adult; D000367:Age Factors; D000368:Aged; D001827:Body Height; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D012737:Sex Factors; D013997:Time Factors; D016138:Walking / Q000502:physiology*; D055815:Young Adult
Aged; Gait; Postural balance; Rehabilitation