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Comparing two methods to quantify physical resilience
Heather E Whitson1, Marissa Ashner2, Virginia B Kraus3
1Duke Aging Center, Duke University School of Medicine, Durham, NC, USA; Department of Medicine, Duke University School of Medicine, Durham, NC, USA; Geriatrics Research Education and Clinical Center (GRECC), Durham Veterans Administration Medical Center, Durham NC, USA.
The Journal of Frailty & Aging
|June 20, 2026
Summary
This study compared two methods for measuring physical resilience in older adults after surgery. Both methods showed similar results for individuals with very high or very low recovery, but varied for moderate recovery.
Area of Science:
- Gerontology
- Biomedical Engineering
- Rehabilitation Science
Background:
- Physical resilience, the ability to recover after a health stressor, is crucial in aging and frailty research.
- Quantifying physical resilience often involves repeated measures of health or function post-stressor.
- Existing methods for measuring resilience have varying approaches and interpretations.
Purpose of the Study:
- To directly compare two distinct methods for quantifying physical resilience: the recovery trajectory (RT) and the expected recovery differential (ERD).
- To evaluate the concordance of RT and ERD in measuring resilience in older adults following a health stressor.
Main Methods:
- Utilized data from 170 older adults undergoing elective knee replacement surgery.
- Assessed physical resilience using repeated measures of pain interference over six months post-surgery.
- Applied both the recovery trajectory (RT) and expected recovery differential (ERD) methods to quantify individual resilience.
Main Results:
- High concordance was observed between RT and ERD for individuals classified at the extremes of high or low recovery.
- The expected recovery differential (ERD) scores showed greater variability among individuals categorized with moderate resilience by the recovery trajectory (RT) method.
- A significant majority (85.9%) of individuals classified as low resilience by RT also demonstrated worse-than-expected recovery using ERD.
Conclusions:
- Both the recovery trajectory (RT) and expected recovery differential (ERD) methods offer valuable approaches for quantifying physical resilience after a health stressor.
- The choice of method for quantifying physical resilience may depend on the specific research question and the expected recovery patterns of the population.
- Further discussion is warranted regarding factors influencing method selection and the interpretation of results in physical resilience research.
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