Cystic Fibrosis (CF)NCT07135869
Muscle Fatigue in People With Cystic Fibrosis: Insight From a Mobile App
An observational study of Cystic Fibrosis (CF), run by Universidad Católica San Antonio de Murcia at 1 site in Spain.
Trial summary
Muscle fitness is an important component of health. For instance, the ability to resist to muscle fatigue development is important for daily functioning. Previous studies have suggested altered muscle function in people with cystic fibrosis. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Cystic Fibrosis (CF)
- What is being tested?
- One minute sit-to-stand test
- How many people
- 100 participants
- Where
- 1 siteSpain
- Study dates
- 1 Sep 2025to 12 May 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Individuals diagnosed with cystic fibrosis, recruited from the registry of the Cystic Fibrosis Association of Murcia, and healthy control participants matched by age and sex.
Who may be able to join
- Clinically stable.
- No changes in medication or pulmonary exacerbations within the two weeks prior to inclusion.
- Not requiring oxygen therapy during the test.
- No history of lung or liver transplants.
Who cannot join
- Any musculoskeletal conditions that could limit or influence test performance.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Reliability and Discriminant Validity of a Mobile App for Detecting Muscle Fatigue in People With Cystic Fibrosis
Muscle fitness is an important component of health. For instance, the ability to resist to muscle fatigue development is important for daily functioning. Previous studies have suggested altered muscle function in people with cystic fibrosis. However, it is unclear whether such findings still apply in the modern era of CF. Several studies suggested that recent improvements in therapeutics, including CFTR modulators, may have positive effects on the skeletal muscles, potentially normalizing the ability to resist to muscle fatigue. However, no studies to date compared muscle fatigue between people with cystic fibrosis and healthy controls in a large sample of patients. One difficulty is that muscle fatigue assessment requires high-cost dynamometric instruments, which also leads to a gap between research and clinical practice. Our research group has created a mobile application based on video analysis of the chair rising test that reports values of time, velocity and power as reliable as devices found in a laboratory environment. The application has been shown to be valid and reproducible for measuring muscle fatigue in healthy people. However, a validation is necessary before recommending its use in people with cystic fibrosis.
Read the detailed description
Objectives: To evaluate the reliability of a mobile app to detect muscle fatigability as decrease in performance after 1minSTS test in people with cystic fibrosis, and to analyze whether muscle fatigability is still increased in people with cystic fibrosis compared to healthy controls.
Methods: A discriminant validity and reliability study designed in accordance with the Guidelines for Reporting Reliability and Agreement Studies will be carried out. The study will include at least 34 participants diagnosed with cystic fibrosis and 34 healthy participants matched for age, sex, and physical activity level. A fatigue protocol will be carried out that will consist of chair rising as many times as possible for 60 seconds. A measurement will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol through the mobile application (Sit to Stand App). The time, velocity and power values derived from the application will be used as fatigability indicators. The differences between the Pre and Post measurements will be indicative of performance fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. Heart rate will be recorded during the fatigue protocol and Post1min, as well as muscle and respiratory effort using the Borg CR10 scale. This experimentation will be repeated twice with a difference of 30 minutes in order to analyze the reliability of the measurements.
The sample size estimation was calculated using G*Power 3.1 software. An estimation was performed for each study objective, and the estimation requiring the largest sample size was selected for the study.
To analyze whether the level of muscle fatigability is reproducible, a minimum acceptable reliability of ρH0 ≥ 0.5 and an expected reliability of ρH1 ≥ 0.8 were selected. For a two-tailed test with a statistical power ≥ 80% and an alpha error of 0.05, the minimum required sample size was reported as 29 participants. To analyze whether mobile application detects muscle fatigability induced by the fatigue test, an expected moderate effect size (d ≥ 0.7) with a statistical power ≥ 80% and an alpha error of 0.05 was selected, resulting in a minimum desirable sample size of 34 participants per group.
- Conditions
- Cystic Fibrosis (CF)
- Being tested
- One minute sit-to-stand test
- Keywords
- Cystic Fibrosis, Fatigue, Fatigability, Mobile app, Validity, Reliability, Muscle power, Strength, Peripheral muscle function
- Medical subject headings
- Cystic Fibrosis, Fatigue
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
One minute sit-to-stand testDiagnostic test
The one minute sit-to-stand test will be used as acute fatigue protocol to generate fatigue.
| Study group | Role | What they receive |
|---|---|---|
| Fatigue protocol for cystic fibrosis | The one minute sit-to-stand test will be used as fatigue protocol. Receives: Diagnostic Test: One minute sit-to-stand test | |
| Fatigue protocol for healthy controls | The one minute sit-to-stand test will be used as fatigue protocol Receives: Diagnostic Test: One minute sit-to-stand test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rising Time
Rising time derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
Measured: Twice separated by 30 minutes to assess reliability.
Sit to Stand Velocity
Velocity derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
Measured: Twice separated by 30 minutes to assess reliability.
Sit to Stand Power
Power derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
Measured: Twice separated by 30 minutes to assess reliability.
One minute sit-to-stand test
The one minute sit-to-stand test will be carried out according to the Guidance and standard operating procedures for functional exercise testing in cystic fibrosis (https://doi.org/10.1183/16000617.0029-2023). The number of repetitions performed during the test will be collected.
Measured: Twice separated by 30 minutes to assess reliability.
Secondary outcomes (4)
Heart rate
Heart rate will be recorded at rest, during the fatigue protocol, and after 1 minute of recovery.
Measured: Twice separated by 30 minutes to assess reliability.
Muscle effort
Muscle effort will be recorded at rest, and after the fatigue protocol using the Borg CR10 scale.
Measured: Twice separated by 30 minutes to assess reliability.
Respiratory effort
Respiratory effort will be recorded at rest, and after the fatigue protocol using the Borg CR10 scale.
Measured: Twice separated by 30 minutes to assess reliability.
Oxygen saturation
Oxygen saturation (SpO2) will be recorded at rest, and after the fatigue protocol (Nadir SpO2).
Measured: Twice separated by 30 minutes to assess reliability.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Aug 2025
- Study start1 Sep 2025
- Primary completion12 May 2026
- Study completion12 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for Cystic Fibrosis (CF)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 100 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidad Católica San Antonio de Murcia
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Juan Diego Ruiz-Cárdenas, Universidad Católica San Antonio de Murcia
- Investigators
- Juan D Ruiz-Cárdenas, PhD, Principal investigator, Universidad Católica San Antonio de Murcia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07135869
- Sponsor's protocol ID
- CE042404
- Status last verified
- May 2026
- First submitted
- 14 May 2025
- Last updated
- 22 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Saynor ZL, Gruet M, McNarry MA, Button B, Morrison L, Wagner M, Sawyer A, Hebestreit H, Radtke T, Urquhart DS; European Cystic Fibrosis Society Exercise Working Group. Guidance and standard operating procedures for functional exercise testing in cystic fibrosis. Eur Respir Rev. 2023 Aug 9;32(169):230029. doi: 10.1183/16000617.0029-2023. Print 2023 Sep 30.
PubMed 37558263Ruiz-Cardenas JD, Rodriguez-Juan JJ, Smart RR, Jakobi JM, Jones GR. Validity and reliability of an iPhone App to assess time, velocity and leg power during a sit-to-stand functional performance test. Gait Posture. 2018 Jan;59:261-266. doi: 10.1016/j.gaitpost.2017.10.029. Epub 2017 Oct 31.
PubMed 29102856Martinez-Garcia MDM, Rodriguez-Juan JJ, Ruiz-Cardenas JD. Influence of sex gap on muscle strength and functional mobility in patients with cystic fibrosis. Appl Physiol Nutr Metab. 2020 Apr;45(4):387-392. doi: 10.1139/apnm-2019-0484. Epub 2019 Sep 17.
PubMed 31526325Ruiz-Cardenas JD, Montemurro A, Del Mar Martinez-Garcia M, Rodriguez-Juan JJ. Concurrent and discriminant validity and reliability of an Android App to assess time, velocity and power during sit-to-stand test in community-dwelling older adults. Aging Clin Exp Res. 2023 Aug;35(8):1631-1640. doi: 10.1007/s40520-023-02451-6. Epub 2023 Jun 12.
PubMed 37306926Souron R, Ruiz-Cardenas JD, Gruet M. The 1-min sit-to-stand test induces a significant and reliable level of neuromuscular fatigability: insights from a mobile app analysis. Eur J Appl Physiol. 2024 Nov;124(11):3291-3301. doi: 10.1007/s00421-024-05537-9. Epub 2024 Jun 20.
PubMed 38900202Gruet M, Troosters T, Verges S. Peripheral muscle abnormalities in cystic fibrosis: Etiology, clinical implications and response to therapeutic interventions. J Cyst Fibros. 2017 Sep;16(5):538-552. doi: 10.1016/j.jcf.2017.02.007. Epub 2017 Mar 2.
PubMed 28262570
Study at a glance
From the registry record, last updated by the sponsor on 22 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Reliability and Discriminant Validity of a Mobile App for Detecting Muscle Fatigue in People With Cystic Fibrosis
- ClinicalTrials.gov ID
- NCT07135869
- Acronym / sponsor ID
- CE042404
- Conditions
- Cystic Fibrosis (CF)
- Keywords
- Cystic Fibrosis, Fatigue, Fatigability, Mobile app, Validity, Reliability, Muscle power, Strength
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 100 participants (actual)
- Lead sponsor
- Universidad Católica San Antonio de MurciaUniversity, hospital or other
- Study start
- 1 Sep 2025 (actual)
- Primary completion
- 12 May 2026 (actual)
- Study completion
- 12 May 2026 (actual)
- First posted
- 22 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Muscle fitness is an important component of health. For instance, the ability to resist to muscle fatigue development is important for daily functioning. Previous studies have suggested altered muscle function in people with cystic fibrosis. However, it is unclear whether such findings still apply in the modern era of CF. Several studies suggested that recent improvements in therapeutics, including CFTR modulators, may have positive effects on the skeletal muscles, potentially normalizing the ability to resist to muscle fatigue. However, no studies to date compared muscle fatigue between people with cystic fibrosis and healthy controls in a large sample of patients. One difficulty is that muscle fatigue assessment requires high-cost dynamometric instruments, which also leads to a gap between research and clinical practice. Our research group has created a mobile application based on video analysis of the chair rising test that reports values of time, velocity and power as reliable as devices found in a laboratory environment. The application has been shown to be valid and reproducible for measuring muscle fatigue in healthy people. However, a validation is necessary before recommending its use in people with cystic fibrosis.
Detailed description
Objectives: To evaluate the reliability of a mobile app to detect muscle fatigability as decrease in performance after 1minSTS test in people with cystic fibrosis, and to analyze whether muscle fatigability is still increased in people with cystic fibrosis compared to healthy controls.
Methods: A discriminant validity and reliability study designed in accordance with the Guidelines for Reporting Reliability and Agreement Studies will be carried out. The study will include at least 34 participants diagnosed with cystic fibrosis and 34 healthy participants matched for age, sex, and physical activity level. A fatigue protocol will be carried out that will consist of chair rising as many times as possible for 60 seconds. A measurement will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol through the mobile application (Sit to Stand App). The time, velocity and power values derived from the application will be used as fatigability indicators. The differences between the Pre and Post measurements will be indicative of performance fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. Heart rate will be recorded during the fatigue protocol and Post1min, as well as muscle and respiratory effort using the Borg CR10 scale. This experimentation will be repeated twice with a difference of 30 minutes in order to analyze the reliability of the measurements.
The sample size estimation was calculated using G*Power 3.1 software. An estimation was performed for each study objective, and the estimation requiring the largest sample size was selected for the study.
To analyze whether the level of muscle fatigability is reproducible, a minimum acceptable reliability of ρH0 ≥ 0.5 and an expected reliability of ρH1 ≥ 0.8 were selected. For a two-tailed test with a statistical power ≥ 80% and an alpha error of 0.05, the minimum required sample size was reported as 29 participants. To analyze whether mobile application detects muscle fatigability induced by the fatigue test, an expected moderate effect size (d ≥ 0.7) with a statistical power ≥ 80% and an alpha error of 0.05 was selected, resulting in a minimum desirable sample size of 34 participants per group.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Fatigue protocol for cystic fibrosis | – | Diagnostic Test: One minute sit-to-stand testThe one minute sit-to-stand test will be used as fatigue protocol. |
| Fatigue protocol for healthy controls | – | Diagnostic Test: One minute sit-to-stand testThe one minute sit-to-stand test will be used as fatigue protocol |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Individuals diagnosed with cystic fibrosis, recruited from the registry of the Cystic Fibrosis Association of Murcia, and healthy control participants matched by age and sex.
Key inclusion criteria (4 listed)
- Clinically stable.
- No changes in medication or pulmonary exacerbations within the two weeks prior to inclusion.
- Not requiring oxygen therapy during the test.
- No history of lung or liver transplants.
Key exclusion criteria (1 listed)
- Any musculoskeletal conditions that could limit or influence test performance.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| One minute sit-to-stand testThe one minute sit-to-stand test will be used as acute fatigue protocol to generate fatigue. | Diagnostic test | Fatigue protocol for cystic fibrosis, Fatigue protocol for healthy controls |
Primary outcome
Rising Time
Time frame: Twice separated by 30 minutes to assess reliability.
Rising time derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
Sit to Stand Velocity
Time frame: Twice separated by 30 minutes to assess reliability.
Velocity derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
Sit to Stand Power
Time frame: Twice separated by 30 minutes to assess reliability.
Power derived from the mobile application (Sit to Stand App) will be carried out before (Pre), immediately after (Post) and one minute after (Post1min) the fatigue protocol. The differences between the Pre and Post measurements will be indicative of fatigability, while the differences between the Post and Post1min measurements will be indicative of recovery. We will follow the protocol published previously (https://doi.org/10.1007/s00421-024-05537-9).
One minute sit-to-stand test
Time frame: Twice separated by 30 minutes to assess reliability.
The one minute sit-to-stand test will be carried out according to the Guidance and standard operating procedures for functional exercise testing in cystic fibrosis (https://doi.org/10.1183/16000617.0029-2023). The number of repetitions performed during the test will be collected.
4 secondary outcomes
Heart rate
Time frame: Twice separated by 30 minutes to assess reliability.
Muscle effort
Time frame: Twice separated by 30 minutes to assess reliability.
Respiratory effort
Time frame: Twice separated by 30 minutes to assess reliability.
Oxygen saturation
Time frame: Twice separated by 30 minutes to assess reliability.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 May 2026.
- Background: PubMed 37558263Saynor ZL, Gruet M, McNarry MA, Button B, Morrison L, Wagner M, Sawyer A, Hebestreit H, Radtke T, Urquhart DS; European Cystic Fibrosis Society Exercise Working Group. Guidance and standard operating procedures for functional exercise testing in cystic fibrosis. Eur Respir Rev. 2023 Aug 9;32(169):230029. doi: 10.1183/16000617.0029-2023. Print 2023 Sep 30.
- Background: PubMed 29102856Ruiz-Cardenas JD, Rodriguez-Juan JJ, Smart RR, Jakobi JM, Jones GR. Validity and reliability of an iPhone App to assess time, velocity and leg power during a sit-to-stand functional performance test. Gait Posture. 2018 Jan;59:261-266. doi: 10.1016/j.gaitpost.2017.10.029. Epub 2017 Oct 31.
- Background: PubMed 31526325Martinez-Garcia MDM, Rodriguez-Juan JJ, Ruiz-Cardenas JD. Influence of sex gap on muscle strength and functional mobility in patients with cystic fibrosis. Appl Physiol Nutr Metab. 2020 Apr;45(4):387-392. doi: 10.1139/apnm-2019-0484. Epub 2019 Sep 17.
- Background: PubMed 37306926Ruiz-Cardenas JD, Montemurro A, Del Mar Martinez-Garcia M, Rodriguez-Juan JJ. Concurrent and discriminant validity and reliability of an Android App to assess time, velocity and power during sit-to-stand test in community-dwelling older adults. Aging Clin Exp Res. 2023 Aug;35(8):1631-1640. doi: 10.1007/s40520-023-02451-6. Epub 2023 Jun 12.
- Background: PubMed 38900202Souron R, Ruiz-Cardenas JD, Gruet M. The 1-min sit-to-stand test induces a significant and reliable level of neuromuscular fatigability: insights from a mobile app analysis. Eur J Appl Physiol. 2024 Nov;124(11):3291-3301. doi: 10.1007/s00421-024-05537-9. Epub 2024 Jun 20.
- Background: PubMed 28262570Gruet M, Troosters T, Verges S. Peripheral muscle abnormalities in cystic fibrosis: Etiology, clinical implications and response to therapeutic interventions. J Cyst Fibros. 2017 Sep;16(5):538-552. doi: 10.1016/j.jcf.2017.02.007. Epub 2017 Mar 2.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Juan D Ruiz-Cárdenas, PhD principal investigator
Universidad Católica San Antonio de Murcia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cystic Fibrosis (CF), run by Universidad Católica San Antonio de Murcia at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rising Time (time frame: Twice separated by 30 minutes to assess reliability.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07135869, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2026.