Validity and Reliability of the International Physical Fitness Questionnaire and the Self-Perceived Health-Related Physical Fitness Questionnaire in Children and Adolescents With JIA and FMF

Pediatric rheumatologic diseases are a group of chronic inflammatory conditions that affect multiple organ systems and are characterized by periods of flare-ups. These conditions encompass diverse groups of disorders, including inflammatory arthritis, autoinflammatory syndromes, vasculitis, and other autoimmune diseases. While Juvenile Idiopathic Arthritis (JIA) is the most common rheumatologic disease in childhood and adolescence, Familial Mediterranean Fever (FMF) is another major and frequently encountered rheumatologic condition in the pediatric population in Turkey. FMF is an autosomal recessive autoinflammatory disease, typically manifesting in childhood and presenting with recurrent episodes of fever and pain. JIA is defined as a heterogeneous group of rheumatic inflammatory diseases characterized by arthritis of unknown etiology that begins before the age of 16 and lasts for at least six weeks.

These pediatric rheumatologic conditions are often marked by pain, which can lead to limited joint mobility, muscle weakness, and fatigue. Individuals experiencing pain symptoms generally exhibit reduced physical function compared to those who are pain-free. Due to the chronic nature of the disease, frequent attacks, and associated symptoms, individuals with FMF and JIA face significant challenges such as a sedentary lifestyle, physical inactivity, decreased muscle strength, fatigue, low physical fitness, and overall reduced physical function. Several studies have consistently demonstrated low levels of physical fitness in children with JIA and adolescents with FMF.

The evaluation of physical fitness in children and adolescents is crucial for identifying developmental differences and allowing for the early detection of potential health problems that may persist into adulthood. While validated and reliable, current physical fitness test batteries frequently encounter practical barriers during field application, including limitations in space, equipment, time constraints, and the need for specialized personnel. These limitations highlight a pressing need for standardized, easily administered scales to facilitate routine clinical assessment.

Inclusion criteria

• Age between 10 and 18 years
• Diagnosis of Familial Mediterranean Fever (FMF) or Juvenile Idiopathic Arthritis (JIA) established by a pediatric rheumatologist at least six months prior
• Voluntary willingness to participate in the study
• Provision of informed consent by both the participant and their parents/guardians
• Ability to ambulate independently, communicate effectively, and comply with the instructions required for the research assessments
• Sufficient literacy to comprehend written instructions and complete study-related materials

Exclusion criteria

• Having a history of a mental or psychological problem that would prevent the understanding of questions or compliance with given instructions.
• Medically unstable conditions (history of hospitalization due to heart or lung disease or a disease flare within the 4 weeks prior to the test).
• Having a history of a chronic disease of cardiovascular, orthopedic, neuromuscular, or neurological origin that could affect physical fitness.
• Having a history of trauma affecting the musculoskeletal system within the last 6 months.