Ultrasound Muscle Biomarkers as Predictors of Isometric Quadriceps Muscle Strength and Handgrip in Healthy Adults: an Observational Study
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Healthy Adult, Muscle Strength, Skeletal Muscle Ultrasound. Basic parameters: 18 years — 89 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
This observational study aims to determine whether ultrasound-derived muscle biomarkers can predict isometric quadriceps muscle strength and handgrip in healthy adults aged 18-89 years. The main questions it aims to answer are: * Which ultrasound muscle characteristics are associated with isometric quadriceps muscle strength and handgrip? * Can ultrasound-derived biomarkers be used to develop predictive models of muscle strength in healthy adults? Participants will undergo: * Ultrasound assessment of the quadriceps and forearm flexor muscles; * Measurement of isometric quadriceps muscle strength and handgrip using standardized dynamometry protocols; * Assessment of functional capacity, mobility and balance; * Completion of questionnaires related to health status, physical activity, nutrition, fatigue and health-related quality of life. The study will also assess the reliability of ultrasound measurements and explore the relationship between ultrasound variables, muscle strength, physical function and health-related factors.
Detailed description
Peripheral muscle strength is an important determinant of physical function, independence and health outcomes. Reduced quadriceps muscle strength and handgrip have been associated with functional limitations, frailty, hospitalization and mortality. Although muscle ultrasound is increasingly used to assess muscle morphology and quality, its ability to predict muscle strength remains incompletely understood.
The MUSCLE-US study is a monocentre observational study designed to investigate the relationship between ultrasound-derived muscle biomarkers and isometric quadriceps muscle strength and handgrip in healthy adults. Participants aged 18-89 years will be recruited from community settings and stratified by age and sex.
Ultrasound assessments will be performed on the quadriceps and forearm flexor muscles using standardized acquisition procedures. First-order variables (e.g., muscle thickness, cross-sectional area, pennation angle, fascicle length), second-order texture features and higher-order ultrasound biomarkers will be extracted and analysed.
Isometric quadriceps muscle strength and handgrip will be measured using standardized dynamometry protocols. Additional assessments will include functional capacity tests, mobility and balance measures, physical activity, nutritional status, fatigue, dyspnoea, health-related quality of life, lifestyle factors and comorbidity profiles.
The primary objective is to identify ultrasound biomarkers associated with quadriceps muscle strength and handgrip, and to develop predictive models of muscle strength. Secondary objectives include assessment of ultrasound measurement reliability and exploration of relationships between ultrasound biomarkers, muscle strength, physical function and health-related characteristics.
Recruitment, assessor training, ultrasound standardisation procedures and reliability analyses will be conducted during the initial phase of the project, followed by the main recruitment and data collection phase and subsequent statistical modelling and dissemination activities.
Primary outcome measures
- Isometric quadriceps muscle strength [Time frame: Day 1]
- Handgrip [Time frame: Day 1]
- Ultrasound-derived muscle biomarkers [Time frame: Day 1]
Secondary outcome measures (10)
- Five-repetition sit-to-stand test [Time frame: Day 1]
- One-minute sit-to-stand test [Time frame: Day 1]
- Timed Up and Go test [Time frame: Day 1]
- Modified Medical Research Council dyspnoea scale [Time frame: Day 1]
- Modified Borg dyspnoea scale [Time frame: Day 1]
- Dyspnoea-12 [Time frame: Day 1]
- Functional Assessment of Chronic Illness Therapy-Fatigue [Time frame: Day 1]
- EuroQol 5-Dimension 5-Level [Time frame: Day 1]
- International Physical Activity Questionnaire-short form [Time frame: Day 1]
- Mini Nutritional Assessment-short form [Time frame: Day 1]
Eligibility criteria
Inclusion criteria
- Healthy adults aged 18-89 years.
- Resident in Spain for at least 5 years.
- Living independently in the community and able to complete all study assessments.
- Able to understand and follow verbal instructions in Spanish.
- Able and willing to provide written informed consent prior to study participation.
Exclusion criteria
- Neurological, musculoskeletal, or systemic disorders affecting muscle strength or mobility.
- Recent surgery or acute injury affecting the upper or lower limbs.
- Recent use of medications affecting the musculoskeletal system (e.g., systemic corticosteroids for >1 week during the previous 6 months or muscle relaxants during the previous week).
- Cognitive or psychiatric conditions limiting participation.
- Pregnancy.
- Recent postpartum period (≤3 months after delivery).
- Presence of clinically relevant pain, fatigue, physical deconditioning, or functional limitations that may interfere with study procedures or measurement validity.
- Acute illness at the time of assessment.
- Uncontrolled hypertension (≥140/90 mmHg).
- Resting peripheral oxygen saturation ≤90%.
- Moderate-to-severe pain (Numeric Rating Scale ≥4/10).
- Any medical condition considered by the investigator to contraindicate study participation.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Observational model
- Case-only
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07647393 · CEIP/2026/2/39