Exercises' Effect on Muscle Strength, Aerobic Capacity and Respiratory Functions in Cystic Fibrosis

March 27, 2026 updated by: Riphah International University

Effects of Upper and Lower Limb Exercises on Muscle Strength, Aerobic Capacity and Respiratory Functions in Children With Cystic Fibrosis

This research aims to evaluate the effects of upper and lower limb exercises on muscle strength and pulmonary function in children diagnosed with CF. While aerobic training is a known component of CF management, resistance training focused on specific limb groups has gained attention for its additional benefits. Upper limb exercises may aid respiratory muscle endurance and thoracic mobility, enhancing pulmonary mechanics. In contrast, lower limb exercises (such as cycling or squats) are associated with improved oxygen consumption (VO₂ peak), enhanced mobility, and greater lower body strength.

This randomized clinical trial will be conducted using a non-probability convenience sampling technique. The study will take place at the pediatric cystic fibrosis centers of Gulab Devi Chest Hospital and The Children's Hospital, Lahore. The targeted population includes children aged 6 to 18 years who have been diagnosed with cystic fibrosis and referred to the physiotherapy department. The study duration will be ten months following the approval of the synopsis. Eligible participants will be children aged between 6 and 18 years, clinically diagnosed with cystic fibrosis, currently stable with no history of hospitalization or significant lung infection in the past month. They should be physically able to participate in exercise and capable of following instructions, with informed consent obtained from their parents or guardians. Children will be excluded if they suffer from other severe lung diseases, cardiovascular or orthopedic conditions that restrict exercise, recent surgery or hospitalization within the last month, or if they are unable to understand instructions. Those dependent on oxygen therapy or ventilator support at all times will also be excluded.

The primary outcome measures will include lung function assessed by spirometry (FVC, FEV1), sputum production recorded through a sputum diary, and aerobic capacity measured by the Incremental Shuttle Walk Test (ISWT). Muscle strength will be evaluated for both upper and lower limbs, using a handheld dynamometer for the upper limbs and the Sit-to-Stand Test for the lower limb

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Cystic fibrosis is a chronic, inherited disorder caused by mutations in the CFTR gene, which disrupt the normal function of epithelial cells involved in fluid transport. This results in the accumulation of thick and sticky mucus in multiple organs, primarily affecting the lungs and digestive system. The disease leads to chronic respiratory infections, obstructive lung disease, pancreatic insufficiency, malabsorption, and other systemic complications. Cystic fibrosis affects approximately 70,000 people globally, with the highest prevalence among individuals of Northern European descent, where approximately one in every 3,000 births is affected, and about one in 25 people are carriers of the faulty gene. Early diagnosis and advancements in treatment have significantly improved the life expectancy of individuals with this condition, with many now surviving well into adulthood.

Children with cystic fibrosis typically present with a range of symptoms such as a persistent cough, recurrent chest infections, wheezing, poor growth despite adequate nutrition, steatorrhea, and clubbing of the fingers. The thick mucus in the airways leads to repeated bacterial infections and airway obstruction, which over time causes irreversible lung damage. Alongside pulmonary issues, these children also face gastrointestinal problems due to enzyme deficiency, liver complications, and difficulties in absorbing vital nutrients. These systemic effects contribute to a cycle of malnutrition, reduced energy, and compromised immune response. Physical inactivity, systemic inflammation, and chronic illness further contribute to muscle weakness, especially in the limbs, reducing a child's ability to perform routine activities.

Treatment for cystic fibrosis is multidisciplinary and includes both medical and therapeutic interventions. Medical treatment primarily focuses on managing infections, improving mucus clearance, and enhancing nutritional status. Common therapies include airway clearance techniques, inhaled bronchodilators, mucolytics like hypertonic saline and dornase alfa, antibiotics (oral and intravenous), pancreatic enzyme replacement therapy, and CFTR modulators such as ivacaftor, lumacaftor/ivacaftor, or the triple combination therapy elexacaftor/tezacaftor/ivacaftor. These medications have transformed the management of cystic fibrosis by targeting the basic genetic defect and improving lung function, quality of life, and survival. However, not all patients are eligible for modulators, and supportive care remains essential for all individuals with cystic fibrosis.

Physical therapy plays a critical role in the comprehensive management of cystic fibrosis. Exercise is now considered a standard component of cystic fibrosis care, as it assists in mucus clearance, improves ventilatory capacity, enhances cardiovascular fitness, and supports musculoskeletal health. Regular physical activity, particularly aerobic and resistance exercises, has shown positive effects on lung function, endurance, and quality of life in children and adolescents with cystic fibrosis. Due to muscle wasting and inactivity, children often exhibit generalized muscle weakness, especially in the limbs. This loss of strength contributes to increased fatigue, reduced mobility, and decreased participation in daily activities. In low- and middle-income countries like Pakistan, limited access to advanced CF care-including genetic testing, airway clearance devices, and multidisciplinary support-places a greater burden on conservative and cost-effective interventions such as physiotherapy. While pharmacologic management remains vital, physiotherapy-based interventions, especially structured exercise programs, offer a non-invasive and sustainable means to improve clinical outcomes in children. However, there is limited localized research on the effectiveness of such interventions within the Pakistani healthcare context, especially in the pediatric population.

Targeted upper and lower limb exercises have recently gained attention in cystic fibrosis rehabilitation programs. Upper limb exercises such as arm cycling, resistance band work, and weight training can improve thoracic mobility, respiratory muscle endurance, and shoulder girdle strength. These improvements may indirectly support respiratory mechanics and facilitate better airway clearance. Lower limb exercises, including squats, cycling, and walking, contribute to improved lower body strength, walking capacity, and overall aerobic endurance. Studies suggest that both types of exercises can have unique benefits in maintaining physical function and slowing disease progression in pediatric patients. Resistance training involving the limbs also helps in increasing lean muscle mass, improving posture, and reducing fatigue during physical tasks.

Despite the growing use of exercise in cystic fibrosis care, there is limited evidence comparing the effectiveness of upper versus lower limb training in children with cystic fibrosis. It remains unclear whether one form of exercise has superior benefits in enhancing muscle strength and pulmonary function or if a combined approach is most effective. This lack of clarity highlights the need for focused research to guide clinical physiotherapy protocols. Evaluating the specific impact of each limb-focused intervention can help physiotherapists design more personalized and effective treatment plans.

The present research aims to assess the effects of upper and lower limb exercise programs on muscle strength and pulmonary function in children with cystic fibrosis. By identifying which approach yields better outcomes in terms of respiratory capacity and physical performance, this study can provide valuable evidence for setting more targeted rehabilitation protocols. Such findings have the potential to enhance the standard of care, reduce the physical decline associated with the disease, and promote long-term health and independence in affected children.

The present study aims to investigate the comparative effects of upper and lower limb exercise regimens on muscle strength and respiratory functions in children with cystic fibrosis. Key respiratory indicators such as Forced Expiratory Volume in 1 second (FEV₁) and Forced Vital Capacity (FVC), alongside validated strength assessments, will be used to evaluate outcomes. This research is intended to provide evidence-based recommendations for integrating tailored exercise programs into early physiotherapeutic management for CF patients, particularly within the pediatric healthcare setting in Pakistan

Study Type

Interventional

Enrollment (Estimated)

22

Phase

  • Not Applicable

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 Locations

  • Pakistan
      • Lahore, Pakistan, 547000
        • Recruiting
        • Gulab Devi Chest Hospital
        • Contact:
        • Principal Investigator:
          • Mahnoor Shakir, MS

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

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Children aged 6-18 years
  • Diagnosed with cystic fibrosis
  • Clinically stable
  • Able to perform exercise
  • Parental/guardian consent provided

Exclusion Criteria:

  • Other severe pulmonary diseases
  • Cardiovascular or orthopedic limitations
  • Surgery or hospitalization within last 1 month
  • Inability to follow instructions
  • Oxygen-dependent or ventilator-dependent patients

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Upper Limb Exercise Training

Participants will undergo upper limb resistance training using an arm cycle ergometer consisting of:

Warm-up: 5-10 minutes at 30-40% peak work rate Training: 2-3 sessions/week Intensity: 50-85% peak resistance Sets: 1-3 sets of 6-15 revolutions with 1-2 minute rest Cool-down: 5-10 minutes low resistance
Other: Arm Cycle Ergometry
Participants will undergo upper limb resistance training using an arm cycle ergometer
Experimental: Lower Limb Exercise Training

Participants will undergo lower limb resistance training using a leg cycle ergometer consisting of:

Warm-up: 5-10 minutes at 30-40% peak work rate Training: 2-3 sessions/week Intensity: 50-85% peak resistance Sets: 1-3 sets of 6-15 revolutions with 1-2 minute rest Cool-down: 5-10 minutes low resistance
Other: Leg Cycle Ergometry
Participants will undergo lower limb resistance training using a leg cycle ergometer

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incremental Shuttle Walk Test (ISWT)
Time Frame: Baseline; 4th Week; 8th Week
The Incremental Shuttle Walk Test (ISWT) is a validated field-based measure of functional aerobic capacity in pediatric populations with chronic respiratory diseases, including cystic fibrosis. It provides a standardized assessment of exercise tolerance and cardiopulmonary endurance. Exercise training programs targeting limb musculature are expected to improve oxygen utilization and functional capacity, which can be objectively captured through changes in ISWT performance over time.
Baseline; 4th Week; 8th Week
Sputum Production (Sputum Diary)
Time Frame: Baseline; 4th Week; 8th Week
Daily sputum volume will be recorded using a structured sputum diary to assess airway clearance effectiveness. Exercise-induced enhancement of mucociliary clearance is expected to influence sputum expectoration patterns in children with cystic fibrosis. Monitoring sputum production provides a clinically relevant secondary outcome reflecting pulmonary secretion management and disease symptom burden.
Baseline; 4th Week; 8th Week
Handheld Dynamometry
Time Frame: Baseline; 4th Week; 8th Week
Upper limb muscle strength will be assessed using handheld dynamometry, which is a reliable and valid method for measuring isometric muscle force in pediatric clinical populations
Baseline; 4th Week; 8th Week
Sit-to-Stand Test
Time Frame: Baseline; 4th Week; 8th Week
Lower limb functional strength will be evaluated using the Sit-to-Stand Test, a simple and reproducible performance-based measure reflecting lower extremity strength and functional mobility.
Baseline; 4th Week; 8th Week
Pulmonary Function Test
Time Frame: Baseline; 4th Week; 8th Week
Forced Expiratory Volume in one second (FEV₁) and Forced Vital Capacity (FVC) are widely accepted clinical indicators of pulmonary function and disease progression in children with cystic fibrosis. These spirometric parameters provide objective measurement of airway obstruction and ventilatory capacity and are recommended outcome measures in exercise-based pulmonary rehabilitation trials. Improvement in FEV₁ and FVC reflects enhanced airway clearance, reduced airflow limitation, and improved respiratory muscle performance following therapeutic exercise interventions.
Baseline; 4th Week; 8th Week

Collaborators and Investigators

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

Sponsor

Riphah International University

Investigators

  • Principal Investigator: Danish Hassan, PhD, Riphah International University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

December 1, 2025

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

March 16, 2026

First Submitted That Met QC Criteria

March 27, 2026

First Posted (Actual)

April 2, 2026

Study Record Updates

Last Update Posted (Actual)

April 2, 2026

Last Update Submitted That Met QC Criteria

March 27, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Mahnoor Shakir REC/25/0306

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

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