THE RELATIONSHIP BETWEEN POSTURAL CHANGES AND TRUNK MUSCLE ENDURANCE IN CHILDREN WITH JUVENILE IDIOPATHIC ARTHRITIS

Background: Body posture is defined as relative biomechanical alignment of body’s head, trunk, and extremities as well as position of the body in the space. Body posture might be altered due to different musculoskeletal pathologies. Juvenile Idiopathic Arthritis (JIA) is a chronic inflammatory disease characterized by musculoskeletal problems including bone and muscle geometry alterations which may lead a deteriorated posture. However, it is not known whether trunk muscle endurance is associated with body posture in children with JIA.Objectives: To investigate the relationship between postural changes and trunk muscle endurance in children with JIA.Methods: Thirty-four children (eighteen female, sixteen male) were included in the study. Postural changes were assessed by a three-dimensional evaluation system (PosturePrint System, Biotonix, Canada). The system provides Posture Index (PI) score which is a composite score from three postural regions including head, ribcage, and pelvis. Higher PI scores indicate a more deteriorated posture. Biering–Sørensen Test (BST), Flexor Endurance Test (FET), Lateral Endurance Test (LET) were used to assess trunk muscle endurance, and Static Scapular Endurance Test (SSET) were used to assess scapular muscle endurance. Spearman Rank Correlation test was employed to determine the possible relationships.Results: Enthesitis related arthritis was the most common JIA subtype in the study (38.2%) followed by oligoarthritis (26.5%), polyarthritis (20.6%), and systemic arthritis (14.7%). Significant negative correlations were detected between SSET and PI-head score (rho= -0.467, p=0.005), SSET and PI-ribcage score (rho= -0.381, p=0.026); FET and PI-head score (rho= -0.469, p=0.005); LET and PI-head score (rho= -0.441, p=0.009).Conclusion: These results indicated that postural displacements of head and ribcage are linked with decreased trunk and scapular muscle endurance in children with JIA. Exercise and physical activity programs targeting muscle endurance may result improvements in posture in these children.