Abstract
Background: Insufficient plantar flexor resistance due to plantar flexor weakness, an impairment common in patient populations, causes substantial gait deficits. The bending stiffness of passive-dynamic ankle-foot orthoses (PD-AFOs) has the capacity to replace lost plantar flexor resistance. Many patients who are prescribed PD-AFOs are older adults. While PD-AFO bending stiffness should be customized for patients, a method to objectively prescribe this stiffness does not exist. Quantifying natural plantar flexor resistance during non-pathological gait could provide a reference value for objectively prescribing PD-AFO bending stiffness. Research question: This study investigated the effect of age on plantar flexor resistance in 113 participants above the age of 65 years. We did so while also considering the confounding influence of gait speed, an aspect known to be reduced with old age. Methods: Ambulatory, community-dwelling older adult women (ages 65–91 years) with no current or recent lower-extremity injuries or surgeries underwent an instrumented gait analysis at a self-selected speed. Plantar flexor resistance was quantified via net ankle quasi-stiffness (NAS) defined as the slope of ankle joint moment-angle curve during late stance. Results: showed that NAS was not significantly influenced by age (r = −0.11, p = 0.12), and that the confounding factor of walking speed had a significant, positive relationship with NAS (r = 0.59, p < 0.001). Significance: By determining that gait speed, not age, is related to NAS in older adults, this study represents the initial step towards objectively prescribing PD-AFO bending stiffness to achieve a targeted gait speed for older adults with plantar flexor weakness.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 311-316 |
| Number of pages | 6 |
| Journal | Gait and Posture |
| Volume | 62 |
| DOIs | |
| State | Published - May 1 2018 |
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Keywords
- Aging
- Ankle-foot orthosis
- Joint stiffness
- Walking speed
ASJC Scopus subject areas
- Biophysics
- Orthopedics and Sports Medicine
- Rehabilitation
Cite this
Net ankle quasi-stiffness is influenced by walking speed but not age for older adult women. / Collins, John D.; Arch, Elisa S.; Crenshaw, Jeremy R.; Bernhardt, Kathie A.; Khosla, Sundeep; Amin, Shreyasee; Kaufman, Kenton R.
In: Gait and Posture, Vol. 62, 01.05.2018, p. 311-316.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Net ankle quasi-stiffness is influenced by walking speed but not age for older adult women
AU - Collins, John D.
AU - Arch, Elisa S.
AU - Crenshaw, Jeremy R.
AU - Bernhardt, Kathie A.
AU - Khosla, Sundeep
AU - Amin, Shreyasee
AU - Kaufman, Kenton R
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Background: Insufficient plantar flexor resistance due to plantar flexor weakness, an impairment common in patient populations, causes substantial gait deficits. The bending stiffness of passive-dynamic ankle-foot orthoses (PD-AFOs) has the capacity to replace lost plantar flexor resistance. Many patients who are prescribed PD-AFOs are older adults. While PD-AFO bending stiffness should be customized for patients, a method to objectively prescribe this stiffness does not exist. Quantifying natural plantar flexor resistance during non-pathological gait could provide a reference value for objectively prescribing PD-AFO bending stiffness. Research question: This study investigated the effect of age on plantar flexor resistance in 113 participants above the age of 65 years. We did so while also considering the confounding influence of gait speed, an aspect known to be reduced with old age. Methods: Ambulatory, community-dwelling older adult women (ages 65–91 years) with no current or recent lower-extremity injuries or surgeries underwent an instrumented gait analysis at a self-selected speed. Plantar flexor resistance was quantified via net ankle quasi-stiffness (NAS) defined as the slope of ankle joint moment-angle curve during late stance. Results: showed that NAS was not significantly influenced by age (r = −0.11, p = 0.12), and that the confounding factor of walking speed had a significant, positive relationship with NAS (r = 0.59, p < 0.001). Significance: By determining that gait speed, not age, is related to NAS in older adults, this study represents the initial step towards objectively prescribing PD-AFO bending stiffness to achieve a targeted gait speed for older adults with plantar flexor weakness.
AB - Background: Insufficient plantar flexor resistance due to plantar flexor weakness, an impairment common in patient populations, causes substantial gait deficits. The bending stiffness of passive-dynamic ankle-foot orthoses (PD-AFOs) has the capacity to replace lost plantar flexor resistance. Many patients who are prescribed PD-AFOs are older adults. While PD-AFO bending stiffness should be customized for patients, a method to objectively prescribe this stiffness does not exist. Quantifying natural plantar flexor resistance during non-pathological gait could provide a reference value for objectively prescribing PD-AFO bending stiffness. Research question: This study investigated the effect of age on plantar flexor resistance in 113 participants above the age of 65 years. We did so while also considering the confounding influence of gait speed, an aspect known to be reduced with old age. Methods: Ambulatory, community-dwelling older adult women (ages 65–91 years) with no current or recent lower-extremity injuries or surgeries underwent an instrumented gait analysis at a self-selected speed. Plantar flexor resistance was quantified via net ankle quasi-stiffness (NAS) defined as the slope of ankle joint moment-angle curve during late stance. Results: showed that NAS was not significantly influenced by age (r = −0.11, p = 0.12), and that the confounding factor of walking speed had a significant, positive relationship with NAS (r = 0.59, p < 0.001). Significance: By determining that gait speed, not age, is related to NAS in older adults, this study represents the initial step towards objectively prescribing PD-AFO bending stiffness to achieve a targeted gait speed for older adults with plantar flexor weakness.
KW - Aging
KW - Ankle-foot orthosis
KW - Joint stiffness
KW - Walking speed
UR - http://www.scopus.com/inward/record.url?scp=85044604986&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044604986&partnerID=8YFLogxK
U2 - 10.1016/j.gaitpost.2018.03.031
DO - 10.1016/j.gaitpost.2018.03.031
M3 - Article
C2 - 29609159
AN - SCOPUS:85044604986
VL - 62
SP - 311
EP - 316
JO - Gait and Posture
JF - Gait and Posture
SN - 0966-6362
ER -