Postural Fitness Protocol in Children and Adolescents: Descriptive Values from the ISQUIOS Program

Back pain is increasingly prevalent during childhood and adolescence, often predicting adult spinal disorders. This study aimed to describe sex-specific anthropometric and "Postural Fitness" characteristics in school-aged children and adolescents and to introduce a standardized, field-based assessment protocol for early screening of postural and functional deficits.

This cross-sectional study included a total of 494 students (8-17 years; 50% girls) from 14 schools in Murcia (Spain). Exclusion criteria included diagnosed spinal pathology or major physical injury, lack of signed informed consent, absence on the testing day, and incomplete Postural Fitness assessment. The "Postural Fitness" protocol included assessments of sagittal spinal alignment (inclinometer), hip range of motion (ROM) (inclinometer with an extendable telescopic arm), pelvic tilt (goniometer with a spirit level system), and trunk muscle endurance (chronometer). Tests were conducted in physical education sessions by trained sports scientists.

Significant sex-based differences were observed. Boys exhibited greater thoracic kyphosis (40.3 ± 9.6° vs. 36.7 ± 9.2°), reduced hip ROM (passive hip extension (PHE): 16.8 ± 8.1°, passive hip flexion with knee extension (PHFKE): 68.9 ± 8.6°), and more posterior pelvic tilt (104.9 ± 8.4° vs. 99.7 ± 8.1°), whereas girls demonstrated increased lumbar lordosis (35.7 ± 8.6° vs. 31.5 ± 8.5°), greater hip ROM (PHE: 18.5 ± 9°, PHFKE: 77.9 ± 13°), and superior trunk extensor endurance (123.2 ± 74.7 s vs. 106.2 ± 69.8 s). Lateral trunk muscle endurance was higher in boys (48.7 ± 31 s vs. 41.4 ± 24.9 s).

The "Postural Fitness" protocol proved feasible in school settings and revealed key sex-based disparities in spinal and neuromuscular profiles. These findings highlight the need for individualized, sex-specific screening and preventive programs to enhance back health during growth. Implementing this protocol may support early identification of modifiable risk factors linked to spinal dysfunction and pain in youth.