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NCT Number: NCT07157644

Exercise Capacity, Muscle Oxygenation, Respiratory Muscle Strength, and Physical Activity Level in Pediatric CF and PCD

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are genetic diseases characterized by chronic respiratory tract infections. In both diseases, impaired mucociliary clearance, recurrent respiratory infections, and persistent inflammation lead to progressive deterioration in respiratory function. This condition limits patients' activities of daily living, leading to physical inactivity and exercise intolerance. Functional exercise capacity in patients with CF and PCD is reduced due to increased respiratory load, musculoskeletal involvement, and nutritional deficiencies. In exercise tests involving the upper and lower extremities, both patient groups exhibited significantly lower performance compared to healthy individuals. Muscle oxygenation is particularly reduced in patients with cystic fibrosis and is associated with inadequate oxygen delivery to peripheral muscles, mitochondrial dysfunction, and increased muscle fatigue. Although studies on muscle oxygenation in PCD patients are limited, it is thought to be affected by similar pathophysiological mechanisms. Respiratory muscle strength is weakened in both patient groups due to chronic cough, hyperinflation, and increased respiratory effort. This is particularly evident in a significant decrease in inspiratory and expiratory muscle strength. The number of studies in the literature evaluating muscle oxygenation, respiratory muscle strength, and physical activity levels in patients with CF and PCD is limited. There are no studies comparing muscle oxygenation between patients with CF and PCD.

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Key information

Conditions

Cystic Fibrosis (CF) Abnormalities, Multiple Behavior Ciliary Motility Disorders Ciliopathies Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Cystic Fibrosis Digestive System Diseases Genetic Diseases, Inborn Infant, Newborn, Diseases Lung Diseases Motor Activity Otorhinolaryngologic Diseases Pancreatic Diseases Primary Ciliary Dyskinesia (PCD) Respiratory Tract Diseases

Age range

6 year–18 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Gazi University Faculty of Health Sciences Department of Cardiopulmonary Physiotherapy and Rehabilitation

Ankara, Çankaya, 06490, Turkey (Türkiye)

About this study

In patients with cystic fibrosis (CF) and primary ciliary dyskinesia (PCD), lower extremity exercise capacity, skeletal muscle function, respiratory muscle strength, and physical activity levels are limited by various pathophysiological mechanisms. In CF patients, lower extremity exercise capacity is significantly reduced due to ventilation limitation, respiratory muscle fatigue, and mitochondrial dysfunction. Early fatigue findings such as delayed oxygen uptake and lactate accumulation have been reported in lower extremity-specific exercise tests. In PCD patients, respiratory workload increases due to ventilation-perfusion mismatch and impaired mucociliary clearance, which can limit muscle oxygen utilization during exercise. Recent studies have shown that PCD patients have lower resting muscle oxygen saturation compared to healthy individuals, but these values are relatively maintained during exercise. In CF, respiratory muscle strength is weakened, particularly at the diaphragm and intercostal muscles, leading to a decrease in ventilatory reserve during exercise. Similarly, submaximal respiratory muscle fatigue and decreased inspiratory muscle strength have been reported in patients with PCD. Regarding physical activity levels, daily activity levels in both patient groups are significantly lower than in healthy peers, and this has been associated with disease progression, muscle dysfunction, and exercise intolerance. Objectively measured studies in children and adolescents with CF have reported that they fall below the recommended daily activity level, and this inadequacy negatively impacts muscle function over time. A similar tendency toward physical inactivity is also found in PCD patients, and this is considered directly related to exercise capacity. The number of studies in the literature evaluating muscle oxygenation, respiratory muscle strength, and physical activity levels in patients with CF and PCD is limited. There are no studies comparing muscle oxygenation in patients with CF and PCD. The aim of our study was to compare functional exercise capacity, muscle oxygenation, respiratory muscle strength, and physical activity in children with CF, PCD, and healthy children.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Cystic fibrosis patients;

  • Patients diagnosed with cystic fibrosis according to the American Cystic Fibrosis Association consensus report
  • Between the ages of 6 and 18
  • Clinically stable conditions

Primary ciliary dyskinesia patients;

  • Patients diagnosed with primary ciliary dyskinesia according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) guidelines
  • Between the ages of 6 and 18
  • Clinically stable conditions

Healthy controls;

  • Agreeing to participate voluntarily in the study
  • Between the ages of 6 and 18

Exclusion criteria

Patients;

  • Uncooperative
  • Orthopedic or neurological disorders that will affect functional capacity
  • Pneumonia or any acute infection

Healthy controls;

  • Chronic disease
  • Uncooperative
  • Orthopedic or neurological disorders that will affect functional capacity

Treatment and study plan

Primary outcomes

  1. Functional Exercise Capacity

    Time frame: First Day

    The six minute walk test (six-MWT) was used to assess functional exercise capacity. The six-MWT was administered according to the criteria of the American Thoracic Society and the European Respiratory Society. Heart rate at rest, after the test, and at the first minute of recovery were assessed using a heart rate monitor (Polar FTI00, China), blood pressure using a sphygmomanometer (Erka Perfect Aneroid, Germany), oxygen saturation using a portable pulse oximeter (Nonin Onyx Vantage 9590, Minnesota, USA), and respiratory frequency (counting the number of breaths taken per minute). The severity of dyspnea and body and leg fatigue was determined using the modified Borg Scale. The six-MWT was repeated twice. Walking distance was expressed in meters and as a percentage of the predicted value. The best walking distance result was selected for analysis. The percentage of the predicted walking distance values was calculated using the reference equation of Gibbons et al.

  2. Muscle oxygenation (Resting muscle oxygen saturation (SmO2rest))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the six-MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  3. Muscle oxygenation (Minimum muscle oxygen saturation (SmO2min))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  4. Muscle oxygenation (Maximum muscle oxygen saturation (SmO2max))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  5. Muscle oxygenation (ΔSmO2)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  6. Muscle oxygenation (SmO2averaged-min)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  7. Muscle oxygenation (SmO2averaged -max)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  8. Muscle oxygenation (ΔSmO2averaged)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  9. Muscle oxygenation (SmO2recovery)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  10. Muscle oxygenation (SmO2recovery-averaged)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  11. Muscle oxygenation (Resting total hemoglobin level (THbrest))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded

  12. Muscle oxygenation (Minumum total hemoglobin level (THbmin))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6PBRT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  13. Muscle oxygenation (Maximum total hemoglobin level (Thbmax))

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  14. Muscle oxygenation (ΔTHb)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT, the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

  15. Muscle oxygenation (THbrecovery)

    Time frame: First Day

    Muscle oxygenation was assessed using the Moxy monitor device (Moxy, Fortiori Design LLC, Minnesota, ABD). During the 6MWT the device was placed on the quadriceps muscle of the dominant leg, and measurements were recorded.

Secondary outcomes

  1. Heart rate

    Time frame: First day

    Heart rate at rest, after the test, and at the first minute of recovery were assessed using a heart rate monitor (Polar FTI00, China).

  2. Blood pressure

    Time frame: First day

    Blood pressure at rest, after the test, and at the first minute of recovery were assessed using a sphygmomanometer (Erka Perfect Aneroid).

  3. Oxygen saturation

    Time frame: First day

    Oxygen saturation at rest, after the test, and at the first minute of recovery were assessed using a portable pulse oximeter (Nonin Onyx Vantage 9590, Minnesota, USA).

  4. Breathing frequency

    Time frame: First day

    Breathing frequency at rest, after the test, and at the first minute of recovery were assessed using a counting the number of breaths taken per minute.

  5. Dyspnea

    Time frame: First day

    The severity of dyspnea was determined using the modified Borg Scale.

  6. Body and leg fatigue

    Time frame: First day

    The severity of body and leg fatigue was determined using the modified Borg Scale.

  7. Pulmonary function (Forced vital capacity (FVC))

    Time frame: First Day

    Pulmonary function was assesed with the spirometry. Dynamic lung volume measurements were made according to ATS and ERS criteria. With the device, forced vital capacity (FVC) was assessed.

  8. Pulmonary function (Forced expiratory volume in the first second (FEV1))

    Time frame: First Day

    Pulmonary function was assessed with the spirometry. Dynamic lung volume measurements were made according to ATS and ERS criteria. With the device, forced expiratory volume in the first second (FEV1) was assessed.

  9. Pulmonary function (FEV1 / FVC)

    Time frame: First Day

    Pulmonary function was assessed with the spirometry. Dynamic lung volume measurements were made according to ATS and ERS criteria. With the device, FEV1 / FVC was assessed.

  10. Pulmonary function (Flow rate 25-75% of forced expiratory volume (FEF 25-75%))

    Time frame: First Day

    Pulmonary function was assessed with the spirometry. Dynamic lung volume measurements were made according to ATS and ERS criteria. With the device, flow rate 25-75% of forced expiratory volume (FEF 25-75%) was assessed.

  11. Pulmonary function (Peak flow rate (PEF))

    Time frame: First Day

    Pulmonary function was assessed with the spirometry. Dynamic lung volume measurements were made according to ATS and ERS criteria. With the device, peak flow rate (PEF) was assessed.

  12. Respiratory Muscle Strength

    Time frame: Second Day

    Maximal inspiratory (MIP) and maximal expiratory (MEP) pressures expressing respiratory muscle strength were measured using a portable mouth pressure measuring device according to American Thoracic Society and European Respiratory Society criteria

  13. Respiratory Muscle Endurance

    Time frame: Second Day

    Incremental threshold loading test

  14. Physical Activity Level (Total energy expenditure)

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Total energy expenditure (joule / day) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  15. Physical activity (Active energy expenditure (joule / day))

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Active energy expenditure (joule / day) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  16. Physical activity (Physical activity time (min / day))

    Time frame: Second day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Physical activity time (min / day)will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  17. Physical activity (Average metabolic equivalent (MET / day))

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Average metabolic equivalent (MET / day) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  18. Physical activity (Number of steps (steps / day))

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Number of steps (steps / day) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  19. Physical activity (Time spent lying down (min / day) days))

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Time spent lying down (min / day) days) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

  20. Physical activity (Sleep time (min / day))

    Time frame: Second Day

    Physical activity will be evaluated with the Multi sensor activity monitor (SenseWear®, Inc Pittsburgh, ABD). The patient will wear the multisensor physical activity monitor over the triceps muscle of the non-dominant arm for 4 continuous days. The patient will be informed about removing the device while taking a bath. Sleep time (min / day) will be measured with the multi-sensor physical activity monitor. The parameters measured over two days will be averaged and analyzed with the "SenseWear® 7.0 Software" program.

Sponsors and collaborators

Lead sponsor

Gazi University

Other

Registry information

Official study title

Comparison of Functional Exercise Capacity, Muscle Oxygenation, Respiratory Muscle Strength, and Physical Activity Level in Pediatric Cystic Fibrosis and Primary Ciliary Dyskinesia

Important dates

Study start
2021
Primary completion
2025
Study completion
2025
First posted
Sep 5, 2025
Registry last updated
Feb 3, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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