Reference Equations and Normative Data for Isometric Quadriceps and Handgrip Muscles STrength in Southern European Populations - RESTart: a Multicentre Study (RESTart)

June 4, 2026 updated by: Nicola S. Diciolla, University of Alcala

This observational study aims to learn about peripheral muscle strength in healthy adults and people with chronic respiratory diseases. The study aims to develop reference data for quadriceps muscle strength and handgrip in adults living in Southern Europe and to assess whether these reference data can be used in people with chronic respiratory diseases.

The main questions it aims to answer are:

  • What are the normal values for quadriceps and handgrip muscle strength in healthy adults aged 18-89 years living in Spain, Portugal and Italy?
  • Can the reference values developed in healthy adults be applied to people with chronic respiratory diseases?

Participants will attend one study visit. During this visit, researchers will:

  • Measure quadriceps muscle strength and handgrip.
  • Collect information about age, sex, height, weight and other health characteristics.
  • Perform simple functional tests related to mobility and physical performance.
  • Ask participants to complete questionnaires about symptoms, physical activity and health-related quality of life.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

The RESTart study (Reference equations and normative data for isometric quadriceps and handgrip STrength in Southern European populations) is a multicentre observational cross-sectional study conducted in Spain, Portugal and Italy.

Peripheral muscle dysfunction, particularly reduced quadriceps muscle strength and handgrip, is common in people with chronic respiratory diseases and is associated with impaired physical function, hospitalisation and mortality. Accurate interpretation of muscle strength measurements requires population-specific reference equations and normative values. However, currently available reference data may not adequately represent Southern European populations.

The primary objective of the study is to develop reference equations and normative values for isometric quadriceps muscle strength and handgrip in healthy adults aged 18-89 years. A secondary objective is to validate/assess clinical application of these reference data in people with chronic respiratory diseases, including chronic obstructive pulmonary disease, interstitial lung disease, asthma, bronchiectasis and cystic fibrosis.

Healthy participants will be recruited from community settings using proportional stratification according to age, sex and country. Participants with chronic respiratory diseases will be recruited from collaborating clinical centres.

Primary outcomes are isometric quadriceps muscle strength and handgrip assessed using standardised dynamometry protocols. Secondary outcomes include functional capacity, mobility and balance, symptoms, physical activity, health-related quality of life, and anthropometric variables; lung function and laboratory parameters only when available from medical records.

The study is expected to provide robust reference equations and normative values for Southern European populations, supporting improved identification and monitoring of peripheral muscle dysfunction in both clinical practice and research.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
2815

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Maria Torres-Lacomba, PT, Ph.D.
  • Phone Number: +34 918 85 48 28
  • Email: maria.torres@uah.es

Study Locations

  • Spain
    • Madrid
      • Alcalá de Henares, Madrid, Spain, 28805
        • University of Alcala
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Community-dwelling healthy adults and adults with chronic respiratory diseases recruited from participating centres in Spain, Portugal and Italy. Healthy participants will be recruited from the general population to develop reference equations and normative values for isometric quadriceps and handgrip strength. Participants with chronic respiratory diseases will be recruited from clinical settings to externally validate the developed reference equations and assess their clinical applicability.

Description

Healthy adults cohort

Inclusion Criteria:

  • Age between 18-89 years.
  • Spanish, Portuguese or Italian, or permanently resident in one of those countries for at least five years.
  • Be community-dwelling (i.e., not hospitalised or institutionalised).
  • Be functionally independent and capable of performing study assessments without assistance or limiting pain.
  • Be able to follow verbal instructions in the local language (Spanish, Portuguese or Italian, as appropriate).
  • Provide written informed consent.

Exclusion Criteria:

  • Acute or chronic musculoskeletal conditions affecting strength: recent fractures, severe osteoarthrosis, ligament injury, acute tendinitis in hands/knee areas, among others.
  • Recent surgery (e.g., within the past six months) in upper or lower limbs.
  • Neuromuscular disorders: Parkinson, multiple sclerosis, stroke, peripheral neuropathies, among others.
  • Non-communicable diseases affecting strength or functional status: active cancer, any unstable heart diseases; any CRD; active rheumatological diseases, obesity (BMI≥30kg/m2), uncontrolled metabolic diseases, among others (not included: controlled dyslipidaemia or arterial hypertension).
  • Cognitive impairments (e.g., dementia) or psychiatric disorders impairing following instructions.
  • Aid devices for walking or compromised functional mobility.
  • Moderate-to-severe pain during the assessment (VAS ≥4).
  • Systemic corticosteroids use for over one week in the previous six months (i.e., risk of muscle atrophy in type II fibres; or steroid myopathy).
  • Muscle relaxants use during the previous week (i.e., risk of not full muscle activation).
  • Pregnancy and postpartum (i.e., potential physiological changes which may alter muscle strength).
  • Current smoking.

Chronic respiratory disease cohort

Inclusion criteria:

  • Aged 18-89 years.
  • Clinical diagnosis of a chronic respiratory disease (e.g., COPD, interstitial lung disease, asthma, bronchiectasis, cystic fibrosis), confirmed by spirometry or clinical records.
  • Clinically stable (no exacerbation within the past four weeks).
  • Capacity to provide informed consent and complete study procedures.

Exclusion criteria:

  • Coexisting conditions which meet the exclusion criteria defined for healthy participants, apart from chronic respiratory diseases.
  • Current requirement for hospitalisation or acute medical management.
  • Severe functional limitation preventing completion of assessments.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Healthy adults cohort
Healthy community-dwelling adults aged 18-89 years recruited in Spain, Portugal and Italy for the development of reference equations and normative data for isometric quadriceps strength and handgrip.
Chronic respiratory disease cohort
Adults with stable chronic respiratory diseases recruited for external validation/clinical application of the developed reference equations and normative values. Eligible conditions include chronic obstructive pulmonary disease, interstitial lung disease, asthma, bronchiectasis and cystic fibrosis.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Isometric quadriceps muscle strength
Time Frame: Day 1
Quadricpes maximum voluntary contraction measured using a handheld dynamometer according to the standardised RESTart protocol. Strength will be recorded as the highest value obtained during the assessment and expressed in kilograms-force (kgf).
Day 1
Handgrip
Time Frame: Day 1
Handgrip mMaximum voluntary contraction measured using a hydraulic handgrip dynamometer according to standardised assessment procedures. Strength will be recorded as the highest value obtained during the assessment and expressed in kilograms-force (kgf).
Day 1

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Five-repetition sit-to-stand test
Time Frame: Day 1
Functional capacity assessed by the time required to complete five sit-to-stand repetitions according to standardised procedures. Results will be expressed in seconds. Lower values indicate better lower-limb functional capacity.
Day 1
One-minute sit-to-stand test
Time Frame: Day 1
Functional capacity assessed as the number of sit-to-stand repetitions completed in one minute according to standardised procedures. Higher values indicate better functional exercise capacity.
Day 1
Timed Up and Go test
Time Frame: Day 1
Mobility and dynamic balance assessed using the Timed Up and Go test. Results will be expressed in seconds. Lower values indicate better mobility and dynamic balance.
Day 1
Modified Medical Research Council dyspnoea scale
Time Frame: Day 1
Dyspnoea severity assessed using the modified Medical Research Council dyspnoea scale. Scores range from 0 to 4, with higher scores indicating greater breathlessness.
Day 1
Modified Borg dyspnoea scale
Time Frame: Day 1
Perceived breathlessness assessed using the modified Borg dyspnoea scale. Scores range from 0 to 10, with higher scores indicating greater breathlessness.
Day 1
Dyspnoea-12
Time Frame: Day 1
Dyspnoea assessed using the Dyspnoea-12 questionnaire. The total score ranges from 0 to 36, with higher scores indicating more severe breathlessness.
Day 1
Functional Assessment of Chronic Illness Therapy-Fatigue
Time Frame: Day 1
Fatigue assessed using the Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire. Scores range from 0 to 52, with higher scores indicating less fatigue.
Day 1
EuroQol 5-Dimension 5-Level
Time Frame: Day 1
Health-related quality of life assessed using the EuroQol 5-Dimension 5-Level (EQ-5D) questionnaire. The index score will be calculated according to the appropriate national value set. Higher scores indicate better health status. Self-rated health assessed using the EQ-5D Visual Analogue Scale. Scores range from 0 to 100, with higher scores indicating better perceived health.
Day 1
St George's Respiratory Questionnaire
Time Frame: Day 1
Respiratory-specific health-related quality of life assessed using the St George's Respiratory Questionnaire. Scores range from 0 to 100, with higher scores indicating worse respiratory health-related quality of life.
Day 1
International Physical Activity Questionnaire-short form
Time Frame: Day 1
Physical activity assessed using the International Physical Activity Questionnaire-short form. Results will be expressed as minutes per week spent in vigorous/moderate/total physical activity, time per week spent walking and hours per day spent in sedentary behaviour (sitting).
Day 1
Mini Nutritional Assessment-short form
Time Frame: Day 1
Nutritional status assessed using the Mini Nutritional Assessment-short form. Scores range from 0 to 14, with higher scores indicating better nutritional status.
Day 1

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Age
Time Frame: Day 1
Participant age recorded in completed years.
Day 1
Weight
Time Frame: Day 1
Participant weight recorded in kilograms.
Day 1
Height
Time Frame: Day 1
Participant height recorded in metres.
Day 1
Body mass index
Time Frame: Day 1
Body mass index calculated as weight divided by height squared.
Day 1
Sex
Time Frame: Day 1
Participant biological sex recorded as female or male.
Day 1
Forced expiratory volume in one second percentage predicted (FEV1%pred)
Time Frame: Day 1
Lung function measured by spirometry when available from medical records.
Day 1
Forced vital capacity percentage predicted (FVC%pred)
Time Frame: Day 1
Lung function measured by spirometry when available from medical records.
Day 1
Systemic inflammation markers
Time Frame: Day 1
CRP, IL-6, eosinophils, fibrinogen, neutrophil elastase, ESR, KL-6, SP-D, FeNO, IgE, calprotectin, if available, from medical records.
Day 1
Charlson Comorbidity Index
Time Frame: Day 1
Comorbidity burden assessed using the Charlson Comorbidity Index. Higher scores indicate greater comorbidity burden.
Day 1
Anatomical Therapeutic Chemical (ATC) Classification System
Time Frame: Day 1
Current medication use classified according to the Anatomical Therapeutic Chemical (ATC) Classification System.
Day 1
Smoking Exposure (pack-year index)
Time Frame: Day 1
Lifetime smoking exposure quantified using the pack-year index, calculated from self-reported smoking history.
Day 1
Alcohol Use Disorders Identification Test-Consumption
Time Frame: Day 1
Alcohol consumption assessed using the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C). Higher scores indicate greater alcohol consumption and increased risk of hazardous drinking.
Day 1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Alcala

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2030

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 31, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 31, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 5, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CEIP/2025/6/174

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data underlying the results reported in publications arising from this study, including demographic characteristics, anthropometric measurements, peripheral muscle strength assessments, functional capacity outcomes, patient-reported outcomes/questionnaire scores, and other variables collected according to the study protocol, upon reasonable request to the principal investigator.

IPD Sharing Time Frame

Beginning 12 months following publication of the primary study results and ending 5 years after publication.

IPD Sharing Access Criteria

Researchers who provide a methodologically sound proposal for secondary analyses consistent with the aims of the study (e.g., individual participant data meta-analyses, validation studies, methodological research, and other scientifically justified secondary analyses).

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings