The Science behind Eforto

Eforto measures WHO recommended biomarkers for vitality capacity

Neuromuscular function

Grip strength

Energy & metabolism

Muscle fatigability
Self-perceived fatigue
Physical exhaustion (CPV-ratio)

Validation & Reliability of Eforto®:

Eforto®’s grip strength and fatigability measurements align with gold standards, offering accurate, consistent, and highly replicable results with strong test-retest reliability. By also capturing fatigue resistance, it provides a crucial insight traditional tools miss for nuanced muscle health monitoring.
Eforto® Matches Gold Standard While Adding Fatigue Insights
De Dobbeleer et al., 2023—Aging Clinical & Experimental Research
Key Finding: Eforto®’s self-monitoring system for grip strength and muscle fatigability achieved and maintained high test–retest reliability. This allows older adults to track decline remotely with clinical-grade accuracy—including fatigue resistance, which static devices cannot capture.

Clinical Sensitivity of Eforto®: A Superior Vigorimeter

Pneumatic bulb–based dynamic grip strength (Vigorimeter) detects functional changes and disease-related decline earlier and more accurately than isometric clamp–based dynamometers.
Dynamic Grip Testing Detects Functional Decline Earlier
De Dobbeleer et al., 2023—Aging Clinical & Experimental Research
Key Findings: The pneumatic bulb-based vigorimeter (Eforto’s tech) detected muscle fatigability loss in older adults even when the traditional dynamometer showed no change, capturing subtle endurance declines essential for identifying early frailty and making it a superior tool for monitoring functional reserve.
Dynamic Grip Strength Outperforms Isometric in Sensitivity
Sipers et al., 2016—Journal of the American Medical Directors Association
Key Finding: The pneumatic vigorimeter is more reproducible, reliable, and practical than the traditional dynamometer for assessing grip strength in geriatric patients. suggesting that for frail or recovering patients, dynamic testing offers a more responsive and geriatric-friendly alternative for tracking functional capacity
Protocol and Device Choice Affect Fatigue Detection
De Dobbeleer et al., 2023 – Gerontology
Key Finding: Vigorimeter-based dynamic testing (measuring pressure over time) was more sensitive in detecting changes in both endurance and strength than traditional static dynamometer testing, which measures only a single maximum squeeze.
Dynamic Grip Strength Mirrors Disease Activity in Arthritis
Coppers & L., 2024 – Ann Rheum Dis
Key Finding: In rheumatoid and psoriatic arthritis, reduced performance on the Vigorimeter strongly correlated with higher disease activity scores, suggesting that dynamic grip testing can serve as a quick, functional biomarker for monitoring inflammatory disease.
Vigorimeter is Unaffected by Hand Geometry
Lee et al., 2024 – Reliability & Validity Study
Key Finding: Vigorimeter measurements remained accurate regardless of hand size or shape, unlike dynamometer, making it a more reliable choice for assessing grip strength in diverse populations where anatomical differences can bias and skew results significantly.

Eforto® Detects Fatigability & Self-Perceived Fatigue Detection in Early Stages

Muscle fatigability and self-perceived fatigue emerge as early, sensitive indicators of declining physical reserve, often preceding measurable strength loss. Recognizing these signs allows for earlier intervention to slow or prevent progression to frailty and sarcopenia.
Early Fatigue Signals Predict Pre-Frailty in Geriatric Patients
Knoop et al., 2021—Experimental Gerontology
Key Findings: In community-dwelling adults aged 80+, lower grip work and higher self-perceived fatigue were strongly linked to pre-frailty status, even before clinical frailty was diagnosed.

The study highlights that muscle fatigability is more sensitive than static strength for detecting early functional decline—allowing preventive interventions before frailty worsens.
Muscle Fatigability Detects Decline Earlier than Maximal Strength
De Dobbeleer et al., 2018—Experimental Gerontology
Key Finding: Comparing the vigorimeter with the dynamometer, researchers found that fatigability measures captured subtle declines in neuromuscular performance that standard grip-strength tests missed. This enhanced early detection of sarcopenia risk in older adults, improving the window for early treatment.
Fatigue as an Early Marker of the Aging Process
Avlund, 2010—Aging Clinical and Experimental Research
Key Finding: Longitudinal evidence shows that self-reported fatigue predicts later onset of disability, frailty, and mortality in older adults, sometimes years before measurable physical limitations appear.

This highlighted that fatigue assessment could thus serve as a low-cost, early-screening tool for aging-related decline.
Clinical Relevance of Fatigability in Older Adults
Eldadah, 2010—PM&R
Key Finding: Fatigability, as the measurable decline in performance over sustained activity, was shown to be a more precise and clinically relevant marker than fatigue alone. It offers a physiological lens into early muscle decline, complementing subjective fatigue reports to guide early sarcopenia interventions.
Capturing Fatigability in Mobility-Intact Older Adults
Simonsick et al., 2014—Journal of the American Geriatrics Society
Key Finding: Even among older adults with preserved mobility, performance-based fatigability tests identified those at high risk for functional decline. This supports its role as a “hidden” early detector for sarcopenia and frailty, well before mobility loss becomes obvious.

Beyond Maximal Strength: Eforto® Adds Fatigability Metrics to the Equation

Maximal strength is only part of the story. By adding fatigability measurements, Eforto® gives a fuller picture of muscle health and can better predict who might struggle with daily activities soon.
Self-Perceived Fatigue, Endurance & Inflammation—Population Evidence (CAMB)
Bautmans, I.; Knoop, V.; Beyer, I.; et al., 2024—European Review of Aging and Physical Activity (CAMB cohort)
Key Findings: Across middle-aged and older adults, self-reported fatigue and muscle endurance consistently correlated with inflammatory markers, indicating their combined use can enhance early detection of physiological decline and inflammatory risk.
Muscle Endurance & Fatigue Predict 1-Year Gait and ADL Decline (BUTTERFLY)
Knoop, V., et al., 2023 — The Journals of Gerontology: Series A
Key Finding: In the BUTTERFLY study, baseline muscle endurance and self-perceived fatigue predicted 1-year declines in gait speed and daily function, even when maximal grip strength did not, highlighting their value in identifying functional risk missed by peak-force testing alone.
Grip Work + Perceived Fatigue Classify Pre-Frailty in Octogenarians
Knoop, V., et al., 2021—Experimental Gerontology
Key Finding: In community-dwelling adults around age 80, combining grip work (strength × endurance) with self-perceived fatigue outperformed maximal grip strength in identifying pre-frailty, correlating with subtle activity limitations and enabling earlier, targeted interventions.
Celecoxib Improves Fatigue Resistance and Mobility in Inflamed Elderly
Mets, T., et al., 2004 — Am J Geriatr Pharmacother
Key Finding: In elderly patients with active inflammation, celecoxib improved muscle fatigue resistance and mobility, supporting fatigability as an early, sensitive endpoint for tracking functional gains from anti-inflammatory therapy.

Beyond Maximal Strength: Eforto® Adds Fatigability Metrics to the Equation

Fatigability reflects not just muscle function but also underlying inflammatory activity and recovery processes. Measuring it provides a dynamic, non-invasive insight into patient health, bridging the gap between clinical symptoms and biological changes.
Muscle Endurance Linked to Fatigue and Inflammation in Elderly Nursing Home Residents
Bautmans, I., et al., 2008 — J Am Geriatr Soc
Key Findings: Muscle endurance in elderly nursing home residents correlates strongly with fatigue perception, mobility levels, and elevated inflammatory markers such as TNF-alpha, IL-6, and HSP70, emphasizing inflammation’s role in age-related muscle decline.
Acute Phase Mediators Negatively Affect Skeletal Muscle Performance in Hospitalized Elderly
Bautmans, I., et al., 2005 — J Gerontol A Biol Sci Med Sci
Key Findings: Circulating acute phase mediators inversely relate to skeletal muscle performance in hospitalized geriatric patients, underscoring the detrimental impact of systemic inflammation on muscle function during acute illness.
Handgrip Performance and IL-6 Are Linked to Fatigue in Elderly Without Active Inflammation
Bautmans, I., et al., 2007 — BMC Geriatr
Key Findings: Handgrip performance correlates inversely with self-perceived fatigue and circulating IL-6 levels in elderly individuals without active inflammation, indicating low-grade inflammation’s subtle impact on muscle function.
Peripheral Muscle Fatigue Correlates with Inflammation in Hospitalized Geriatric Patients
Arnold, P. K., et al., 2017—Experimental Gerontology
Key Findings: Peripheral muscle fatigue in hospitalized geriatric patients is closely associated with circulating inflammatory markers, suggesting systemic inflammation contributes significantly to muscle fatigue in acute geriatric illness.
Surgery-Induced Inflammation Impacts Muscle Endurance and Fatigue in Older Adults
Bautmans, I., et al., 2010 — J Gerontol A Biol Sci Med Sci
Key Findings: Surgery-induced inflammation negatively impacts muscle endurance and increases self-perceived fatigue, with effects more pronounced in older patients, underlining inflammation’s role in postoperative muscle function decline.
Inflammaging Contributes to Skeletal Muscle Decline in Elderly Men
Zembron-Lacny, A., et al., 2019 — Am J Men’s Health
Key Findings: Chronic low-grade inflammation (“inflammaging”) is linked with deteriorated skeletal muscle properties in elderly men, reinforcing the concept that age-related inflammation contributes to sarcopenia and muscle functional decline.
Grip Work as a Biomarker of Muscle Endurance and Inflammation in Elderly Persons
Bautmans, I., et al., 2011 — J Nutr Health Aging
Key Findings: Grip work during sustained maximal contraction is a valid measure linked to physical dependency and inflammation in elderly persons, supporting its use as a functional biomarker of muscle endurance.
NSAID Treatment Improves Muscle Performance in Acute Inflammation
Beyer, I., et al., 2011 — BMC Musculoskelet Disord
Key Findings: In geriatric patients with infection-related inflammation, piroxicam improved muscle performance and fatigue resistance more than placebo, highlighting fatigability metrics as a sensitive and practical outcome for monitoring short-term treatment effects in acute care.
Circulating Acute-Phase Mediators Link to Skeletal Muscle Performance
Bautmans, I., et al., 2005 — J Gerontol A Biol Sci Med Sci
Key Findings: In hospitalized geriatric patients, acute inflammation was linked to poorer muscle performance and greater fatigability, independent of strength measures, supporting fatigability testing as a non-invasive proxy for inflammatory burden.

Eforto related publications

The Eforto protocol, its methods and unique bulb form factor, is grounded in scientific and clinical evidence, reflecting our deep commitment to research.

Ongoing Clinical Research With Eforto®:

Several clinical trials across Europe are already leveraging Eforto®’s innovative measurement technology to explore resilience, recovery, and healthy aging.

Advance Your Research with Eforto®

Contact us to discover how our validated technology can elevate your study design and enhance outcome sensitivity.

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