Effects of Physical Activity and Physical Fitness on Inflammation, Clinical Outcomes, and Quality of Life in Pediatric Inflammatory Bowel Disease
Phase: NA
Conditions: Inflamatory Bowel Disease (Crohn&#39;s and Ulcerative Colitis), Inflamatory Bowel Disease
Sponsor: Universidad Complutense de Madrid

STUDY PROTOCOL 
 
Official Study Title 
Physical Activity and Fitness in Pediatric Inflammatory Bowel Disease (PAFIT–IBD) 
 
Clinical Trials Identifier  
NCT Number: NCT07484620 
 
Document Type 
Study Protocol  
 
Document Date 
10 March 2026 
 
Study Sponsor / Responsible Organization 
Universidad Rey Juan Carlos (URJC) 
Madrid, Spain 
 
Collaborating Institution 
Hospital Infantil Universitario Niño Jesús 
Madrid, Spain 
 
Study Description 
This document contains the Study Protocol for the study titled “Physical Activity and Fitness in 
Pediatric Inflammatory Bowel Disease (PAFIT–IBD)”, a prospective single-arm interventional 
study evaluating the effects of a structured physical activity intervention on physical activity, 
physical fitness, inflammation, and clinical outcomes in children and adolescents with 
inflammatory bowel disease. 
 
Important Note 
This document was prepared for submission to ClinicalTrials.gov in accordance with the 
requirements of the Protocol Registration and Results System (PRS). Uploaded documents 
may be posted publicly on the ClinicalTrials.gov website after PRS review. 
This document does not contain any personally identifiable information about study 
participants. 
 

1. ABSTRACT 
Pediatric inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is 
a chronic condition associated with persistent intestinal inflammation, fatigue, reduced physical 
fitness, and impaired quality of life. Despite advances in treatment, many pediatric patients 
present functional limitations that are not systematically addressed in clinical practice. 
The aim of this study is to evaluate the effect of physical activity (PA) and physical fitness on 
inflammation, clinical outcomes, and quality of life in children and adolescents with IBD. 
This is a hospital-based prospective single-arm interventional study that includes a structured 
12-week physical activity intervention and medium-term follow-up (6–12 months). 
Participants will include children and adolescents aged 6–17 years with a confirmed diagnosis of 
IBD in clinical remission or mild-to-moderate disease activity. 
The intervention will consist of a supervised physical activity program adapted to the 
participant’s age and clinical condition. 
The primary outcome will be the change in physical fitness assessed using the ALPHA fitness 
test battery. 
Secondary outcomes include: 
• 
Objective inflammatory markers (fecal calprotectin, C-reactive protein) 
• 
Disease activity indices 
• 
Body composition 
• 
Quality of life 
• 
Fatigue 
• 
Cognitive function 
• 
Mental health 
• 
Nutritional status 
The study involves minimal risk, comparable to regular physical activity, and is expected to 
generate potential benefits for participants and valuable knowledge to improve the comprehensive 
management of pediatric IBD. 
The project will be conducted in accordance with ethical and legal principles governing research 
involving minors. 
 
2. BACKGROUND AND RATIONALE 
Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is a chronic 
condition that frequently begins during childhood and adolescence. 
In pediatric populations, IBD is associated not only with persistent intestinal inflammation but 
also with several extraintestinal manifestations, including: 
• 
fatigue 
• 
musculoskeletal pain 

• 
growth delay 
• 
mood disturbances 
• 
reduced quality of life. 
Several studies have shown that children and adolescents with IBD have lower levels of physical 
activity and poorer physical fitness compared with healthy peers. 
Low cardiorespiratory and muscular fitness may contribute to: 
• 
increased systemic inflammation 
• 
poorer disease control 
• 
greater symptom burden. 
However, most existing studies are cross-sectional, rely on self-reported physical activity, and 
do not comprehensively assess physical fitness using objective testing. 
Physical activity and physical fitness are modifiable lifestyle factors with low cost and 
potentially high clinical impact. 
In the general pediatric population, better physical fitness is associated with: 
• 
lower inflammation 
• 
improved mental health 
• 
better cognitive performance. 
Nevertheless, in pediatric IBD there is a clear lack of well-designed hospital-based studies 
evaluating the combined relationship between: 
• 
physical activity 
• 
physical fitness 
• 
objective inflammation 
• 
clinically relevant outcomes. 
This project proposes an integrated hospital-based study to evaluate the role of physical activity 
and physical fitness as prognostic factors for clinical evolution, inflammation, and quality of life 
in children and adolescents with IBD, as well as the impact of a structured physical activity 
intervention. 
 
3. HYPOTHESES 
Children and adolescents with IBD who present higher levels of physical activity and better 
physical fitness will show lower levels of objective inflammation and lower disease activity. 
Better physical fitness will be associated with lower fatigue, improved quality of life, and better 
cognitive functioning. 
Physical fitness will act as a mediator in the relationship between physical activity and clinical 
outcomes in pediatric IBD. 

A structured physical activity intervention will improve physical fitness, reduce inflammation, 
and improve quality of life in children and adolescents with IBD. 
 
4. OBJECTIVES 
General Objective 
To evaluate the association between physical activity, physical fitness, and clinical outcomes in 
children and adolescents with IBD, as well as the effect of a structured physical activity 
intervention. 
 
Specific Objectives 
• 
To describe levels of physical activity and physical fitness in children and adolescents 
with IBD. 
• 
To analyze the association between physical activity and objective inflammatory markers. 
• 
To analyze the relationship between physical fitness and disease activity, fatigue, and 
quality of life. 
• 
To evaluate the association between physical fitness and cognitive and mental health 
variables. 
• 
To analyze whether physical fitness mediates the relationship between physical activity 
and clinical outcomes. 
• 
To evaluate the effect of a structured physical activity intervention on physical fitness, 
inflammation, and quality of life. 
• 
To analyze the sustainability of these effects at medium-term follow-up (6–12 months). 
 
5. STUDY DESIGN 
Hospital-based prospective interventional study, single-arm, with baseline, post-intervention, and 
follow-up assessments. 
Phase 1 – Observational phase 
Cross-sectional and longitudinal evaluation of participants. 
Phase 2 – Intervention phase 
Prospective, non-randomized single-arm physical activity intervention. 
Phase 3 – Follow-up phase 
Medium-term follow-up (6–12 months) after baseline or intervention completion to evaluate 
clinical, inflammatory, and functional evolution. 
 
 
 

Study Setting 
Pediatric Gastroenterology clinics and functional areas of Hospital Infantil Universitario Niño 
Jesús (Madrid, Spain), in collaboration with Universidad Rey Juan Carlos (Madrid, Spain). 
 
6. PARTICIPANTS 
Inclusion Criteria 
• 
Age between 6 and 17 years 
• 
Confirmed diagnosis of Crohn’s disease or ulcerative colitis 
• 
Clinical remission or mild-to-moderate disease activity 
• 
Follow-up at a pediatric gastroenterology outpatient clinic 
• 
Written informed consent from a legal guardian 
 
Exclusion Criteria 
• 
Severe disease flare at enrollment 
• 
Medical contraindication to physical exercise 
• 
Major surgery in the previous 3 months 
• 
Other severe chronic diseases limiting physical activity 
• 
Cognitive or behavioral conditions preventing safe participation 
 
Sample Size 
The sample size was calculated considering the change in cardiorespiratory fitness, assessed 
using the 20-meter shuttle run test (20mSRT). 
The intervention follows a pre–post design, where each participant serves as their own control. 
Based on previous literature in pediatric chronic disease populations: 
• 
Expected effect size: Cohen’s d = 0.5 
• 
Significance level: α = 0.05 
• 
Statistical power: 80% 
The minimum required sample size is 34 participants. 
Considering expected drop-out rates of 15–30%, the target sample size is approximately 100 
participants. 
This sample size is considered realistic, ethically justified, and appropriate for the objectives of 
the study. 
 
7. VARIABLES 

7.1 Primary Variables 
Physical Fitness 
Assessed using the ALPHA fitness test battery, adapted for the hospital environment: 
Cardiorespiratory fitness 
• 
20-meter shuttle run test 
Muscular strength 
• 
Handgrip strength 
• 
Standing long jump 
 
7.2 Secondary Variables 
Physical Fitness 
Speed and agility 
• 
4 × 10 m test 
 
Physical Activity 
Objectively measured using accelerometry for 7 consecutive days. 
Main variables: 
• 
Moderate-to-vigorous physical activity (MVPA, min/day) 
• 
Total sedentary time 
• 
Physical activity patterns 
Subjective measures: 
• 
PAQ-C (children) 
• 
PAQ-A (adolescents) 
Inflammation and disease activity 
Inflammatory biomarkers: 
• 
Fecal calprotectin 
• 
C-reactive protein (CRP) 
Disease activity indices: 
• 
PCDAI (Crohn’s disease) 
• 
PUCAI (ulcerative colitis) 
 
Neurocognition and Mental Health 

Attention and executive function 
• 
BENCI computerized neuropsychological battery 
Fatigue 
• 
PedsQL Fatigue Module 
ADHD symptoms 
• 
ADHD Rating Scale 
Anxiety and depression 
• 
RCADS 
 
Quality of Life and Daily Functioning 
• 
IMPACT-III questionnaire (IBD-specific quality of life) 
• 
Academic performance 
 
Diet Quality 
• 
KIDMED index 
 
Body composition 
• 
Lean body mass 
• 
Body fat percentage 
• 
BMI z-score 
 
8. INTERVENTION 
The intervention consists of a structured physical activity program lasting approximately 12 
weeks, designed for children and adolescents with IBD. 
The program includes 2–3 weekly sessions combining: 
• 
moderate-intensity aerobic exercise 
• 
functional strength exercises. 
Sessions will be adapted to each participant’s age, functional level, and clinical condition. 
Participants will serve as their own controls through pre- and post-intervention comparisons, 
as well as medium-term follow-up analyses. 
Some aerobic sessions will be conducted in Retiro Park, located opposite the hospital. 
Safety precautions include: 
• 
group supervision by research staff 

• 
use of pedestrian crossings 
• 
cancellation or adaptation of outdoor sessions during adverse weather. 
The intervention is considered minimal risk, comparable to usual physical activity. 
 
9. STUDY TIMELINE 
The study will last approximately 18 months, starting in January 2026. 
Phase 0 – Preparation and ethical approval (January 2026) 
• 
Ethics committee approval 
• 
Investigator team coordination 
• 
Staff training 
• 
Development of electronic forms 
• 
Preparation of intervention materials 
Phase 1 – Recruitment and baseline assessment (Feb–Mar 2026) 
• 
Identification of eligible participants 
• 
Informed consent and child assent 
• 
Baseline assessments 
Phase 2 – Physical activity intervention (Mar–Jun 2026) 
• 
12-week structured intervention 
• 
Continuous monitoring of adherence and adverse events 
Phase 3 – Post-intervention assessment (Jun–Jul 2026) 
• 
Repeat baseline assessments 
• 
Record clinical and functional changes 
Phase 4 – Follow-up (Sep 2026 – Mar 2027) 
• 
Reassessment at 6–12 months 
• 
Monitoring clinical outcomes 
Phase 5 – Data analysis and dissemination (Apr–Jun 2027) 
• 
Statistical analysis 
• 
Preparation of scientific manuscripts 
• 
Communication of results 
 
10. DISSEMINATION PLAN 
Results will be disseminated through: 

• 
peer-reviewed international journals 
• 
national and international scientific conferences. 
Approximately five scientific manuscripts are expected, addressing different objectives and 
phases of the study. 
When possible, participating families will receive a lay summary of the global study results. 
 
11. ETHICAL CONSIDERATIONS 
The study involves minimal risk, comparable to regular physical activity. 
Safety monitoring and adverse event reporting will be implemented. 
The study will follow: 
• 
The Declaration of Helsinki 
• 
National regulations governing research involving minors. 
Ethical approval will be requested from the Research Ethics Committee of Hospital Infantil 
Universitario Niño Jesús (Madrid, Spain). 
 
12. INFORMED CONSENT 
Written informed consent will be obtained from the legal guardian and assent from the child when 
appropriate using electronic forms. 
All questionnaires and forms will be administered through Microsoft Forms within the 
institutional Microsoft 365 environment of Universidad Rey Juan Carlos. 
Participants will be identified using pseudonymized study codes, and identifiable information 
will be stored separately. 
Data handling will comply with: 
• 
General Data Protection Regulation (EU 2016/679) 
• 
Spanish Organic Law 3/2018 on Data Protection.