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

NCT07617558 | Not Yet Recruiting

• 1 other identifier: hXEd9X7x
• Study Type: observational
• Target: 100
• Locations: 0 countries
• Sites: N/A

Brief Summary

Juvenile Idiopathic Arthritis (JIA) and Familial Mediterranean Fever (FMF), two of the most prevalent pediatric rheumatologic diseases, significantly compromise the physical health of children and adolescents, leading to reduced physical fitness, muscle weakness, and a sedentary lifestyle. This study aims to evaluate the validity and reliability of the International Fitness Scale (IFS) and the Self-Perceived Health-Related Fitness Questionnaire for Children (PHFQ-C) as assessment tools for physical fitness in individuals diagnosed with JIA and FMF. Our hypothesis is that these scales will provide demonstrably reliable and valid data within this patient population. To test this, 98 patients aged 10-18 years, recruited from the Pediatric Rheumatology Clinic at Istanbul Faculty of Medicine, will participate. Their physical fitness will be objectively measured using the FitnessGram Test Battery (assessing aerobic capacity, muscular strength, and flexibility), while the IFS and PHFQ-C will be administered online. Statistical analysis, conducted using SPSS 25.0, will employ Pearson/Spearman correlation for validity and Cronbach's alpha and test-retest Intraclass Correlation Coefficient (ICC) for reliability. The expected findings will confirm the utility of the IFS and PHFQ-C as practical, economical, and valid instruments for assessing physical fitness in children and adolescents with JIA/FMF. Promoting the widespread use of these scales in clinical settings will facilitate the rapid and convenient evaluation of patients' fitness levels, thereby enabling the development of early, targeted intervention strategies and ultimately contributing to an improved quality of life. Furthermore, by offering a validated alternative to standard test batteries-which are often cumbersome due to requirements for time, specialized equipment, and expert personnel-this work will make a valuable methodological contribution to the existing scientific literature.

Conditions

Juvenile Idiopathic Arthritis; Familial Mediterranean Fever

Keywords

Juvenile Idiopathic Arthritis; Familial Mediterranean Fever; physical fitness; reliability; validity

Outcome Measures

Primary Outcomes (2)

• Self-Perceived Health-Related Physical Fitness Questionnaire

  The scale developed by Fox and Corbin (1989) assesses self-perceived physical fitness based on a four-factor structure, consisting of cardiovascular endurance, muscular flexibility, muscular strength, and body composition (28). Subsequently, a muscular endurance factor was added, yielding the final version of the questionnaire with five dimensions of physical fitness. The instrument comprises two main sections. In the first section, five key components-cardiorespiratory fitness, muscular fitness, flexibility, and body composition-are evaluated using a scale scored from 1 to 5. In the second section, children assess their own physical fitness in comparison with their peers. The total score obtained from the questionnaire ranges from 9 to 45. Except for the body composition item, lower scores on the other items are associated with better physical fitness. In prepubertal Spanish children, ASFU-C exhibited high test-retest reliability and moderate validity across other variables.

  Until one week after registration

• International Fitness Scale

  The instrument developed by Ortega et al. is a practical self-administered scale designed to assess physical fitness in individuals (24). The scale consists of five domains: overall physical fitness, cardiorespiratory endurance, muscular strength, speed/agility, and flexibility. To examine various components of physical fitness, a five-point Likert scale is employed, ranging from "very good" to "good," "average," "poor," and "very poor." Having been translated into nine different languages, the scale has demonstrated structural reliability and validity across diverse populations, including adolescent cohorts in Brazil, Spain, Colombia, Chile, and several European countries (24, 27).

  Until one week after the registration date

Secondary Outcomes (1)

• FitnessGram Test Battery

  Until one week after registration

Study Arms (1)

Patients diagnosed with Juvenile Idiopathic Arthritis or Familial Mediterranean Disease

All participants consist of patients aged 10-18 who are followed by the Istanbul Faculty of Medicine Pediatric Rheumatology Outpatient Clinic and have been diagnosed with Juvenile Idiopathic Arthritis (JIA) or Familial Mediterranean Fever (FMF).

Eligibility Criteria

• Age: 10 Years - 18 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

It is generally recommended that the sample size for validity and reliability studies be 5 to 10 times the total number of items (30). In light of this information in the literature, and given that the International Physical Fitness Questionnaire (IPFQ) and the Self-Perceived Health-Related Physical Fitness Questionnaire for Children (SPFQ-C) have a total of 14 items, the sample size for our study was determined to be 98 participants. Consequently, we plan to include a minimum of 100 patients diagnosed with JIA or FMF in our study. Participants will be recruited from individuals who are being followed up at the Pediatric Rheumatology Subdivision of the Department of Internal Medical Sciences at Istanbul University Faculty of Medicine and who meet the inclusion criteria.

You may qualify if:

• 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

You may not qualify if:

• 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.

Sponsors & Collaborators

• Istanbul University - Cerrahpasa: lead

MeSH Terms

Conditions

Arthritis, Juvenile; Familial Mediterranean Fever

Condition Hierarchy (Ancestors)

Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Connective Tissue Diseases; Skin and Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases; Hereditary Autoinflammatory Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Study Officials

• Nilay Arman, Associate Professor

  Istanbul University - Cerrahpasa

  STUDY CHAIR

Central Study Contacts

Nilay Arman, Associate Professor

CONTACT

+90 (553) 455 87 07; nilayarman@iuc.edu.tr

Beyza N Yumak, MSc

CONTACT

+90 (539) 856 14 70; beyzanurymk@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 7 Days
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD Student

Study Record Dates

• First Submitted: November 27, 2025
• First Posted: June 1, 2026
• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): October 30, 2026
• Study Completion (Estimated): October 30, 2026
• Last Updated: June 1, 2026

Record last verified: 2026-05