OBJECTIVE: Recently, handgrip, knee extensor and respiratory muscle strength were proposed as candidate biomarkers to assess the neuromuscular function of vitality capacity in older persons. This umbrella review aims to provide an overview of the available instruments and their measurement properties to assess these biomarkers.
METHODS: The databases PubMed, Web of Science and Embase were systematically screened for systematic reviews and meta-analyses reporting on handgrip, knee extensor or respiratory muscle strength assessments, resulting in 7,555 articles. The COSMIN checklist was used to appraise psychometric properties and the AMSTAR for assessing methodological quality.
RESULTS: Twenty-seven systematic reviews were included in this study. Some of the identified reviews described the psychometric properties of the assessment tools. We found five assessment tools that can be used to measure neuromuscular function in the context of healthy ageing. Those are the handheld dynamometer for handgrip strength, the dynamometer for knee extensor strength and regarding respiratory muscle strength, the sniff nasal inspiratory pressure, maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP).
CONCLUSIONS: The handheld dynamometer for hand grip strength, the dynamometer for knee extensor strength, sniff nasal inspiratory pressure, MIP and MEP were identified. Therefore, these assessments could be used to identify community-dwelling older adults at risk for a declined neuromuscular function in the context of vitality capacity.

Vitality capacity (VC) is a key domain of intrinsic capacity (IC) and is the underlying biophysiological aspect of IC. Energy and metabolism (E&M) is one of the domains of VC. Fatigue is one of the main characteristics of E&M.
The aims of this umbrella review are (i) to identify the available instruments suitable for measuring fatigue in community-dwelling older adults and (ii) to critically review the measurement properties of the identified instruments.
Umbrella review.
Healthcare.
Community-dwelling older adults.
PubMed and Web of Knowledge were systematically screened for systematic reviews and meta-analysis reporting on fatigue instruments resulting in 2,263 articles (last search 5 December 2022). The COSMIN checklist was used to appraise psychometric properties and the AMSTAR for assessing methodological quality. Data on fatigue instruments, construct, reference period, assessment method, validated population, reliability, validity, responsiveness and predictive validity on negative health outcomes were extracted.
10 systematic reviews and 1 meta-analysis were included in this study. 70 fatigue instruments were identified in the literature and 21 were originally designed for fatigue. The Fatigue Severity Scale (FSS), Pittsburgh Fatigability Scale (PFS) and Visual Analogue scale (VAS-F), Fatigue Impact Scale (FIS) and the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) presented good psychometric properties.
The FSS, FIS, FACIT-F, PFS and the VAS-F presented good psychometric properties in various conditions. Therefore, these instruments could be used to quantify trajectories in the domain E&M in the context of VC in community-dwelling older adults.