As the global population ages, preserving healthspan, functional independence, and resilience has become a major priority in aging research. Understanding why some older adults maintain function while others experience persistent physical or cognitive decline, particularly after physiological stressors such as infection, surgery, hospitalization, or critical illness, requires robust and translatable research methods.

This Topical Collection will highlight experimental and clinical methods for assessing healthspan, functional decline, and resilience across model systems and human populations. We also welcome studies aimed at understanding the etiology, physiology, and molecular mechanisms that contribute to the heterogeneity of aging outcomes and resilience, as well as innovative approaches that link these biological processes to clinically meaningful measures of function. Relevant topics may include functional phenotyping, frailty assessment, physical and cognitive function, skeletal muscle health, biomarker discovery, imaging, multi-omics, and longitudinal approaches that connect biological mechanisms of aging with clinically meaningful outcomes.

By bringing together reproducible translational methods and mechanistic insights, this collection will provide practical tools for the aging research community, improve cross-study comparability, and accelerate the translation of biological discoveries into strategies that promote resilience, functional recovery, and healthy aging.