Physical Activity and Fitness in Pediatric Inflammatory Bowel Disease

Pediatric inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic condition associated not only with intestinal inflammation but also with reduced physical fitness, fatigue, impaired quality of life, and psychosocial difficulties. Although physical activity and physical fitness are recognized as important determinants of health in the general pediatric population, their role as modifiable prognostic factors in children and adolescents with IBD remains insufficiently studied, particularly using objective measures and longitudinal designs in hospital settings.

The present hospital-based study aims to investigate the effects of physical activity and physical fitness on inflammation, clinical outcomes, and quality of life in children and adolescents with IBD. The project comprises three phases: (1) an observational cross-sectional and longitudinal assessment, (2) a randomized controlled trial (RCT) evaluating a structured physical activity intervention, and (3) a medium-term follow-up at 6-12 months.

Physical activity will be assessed objectively using accelerometry and subjectively using validated questionnaires. Physical fitness will be evaluated with the ALPHA fitness battery adapted to the hospital setting, with cardiorespiratory fitness assessed by the 20-meter shuttle run test as the primary outcome of the RCT. Clinical outcomes will include objective inflammatory markers (fecal calprotectin and C-reactive protein), disease activity indices (PCDAI or PUCAI), musculoskeletal health, fatigue, cognitive functioning, and health-related quality of life. Nutritional status and dietary quality will also be assessed, and selected biological markers will be analyzed in a subsample.

The RCT will examine whether a 12-week supervised physical activity program improves cardiorespiratory fitness compared with usual care, and whether changes in fitness are accompanied by improvements in inflammatory burden and patient-reported outcomes. Longitudinal analyses will explore the sustainability of these effects over time.

This study will provide comprehensive, objective evidence on the role of physical activity and physical fitness as modifiable factors in pediatric IBD. The results are expected to inform clinical practice, support the integration of structured physical activity into multidisciplinary care, and contribute high-quality data for publication in international peer-reviewed journals.