A new nine-type classification of body posture in children

Introduction
Sagittal spinal curvatures in children are most commonly assessed using isolated measurements, without consideration of compensatory mechanisms in adjacent anatomical segments. Such an approach limits both diagnostic accuracy and the clinical utility of existing postural classification systems. This study presents a comprehensive, nine-type postural classification based on the combined analysis of thoracic kyphosis and lumbar lordosis values in school-aged children.

Material and methods
A cross-sectional observational study was conducted involving 303 children aged 10–12 years (47.2% girls). Body posture was assessed using the DIERS Formetric III 4D raster stereography system under standardised laboratory conditions.

Results
Normal posture was identified in 29.0% of participants, whereas postural deviations were present in 71.0%. The most frequently observed abnormal patterns were reduced thoracic kyphosis with normal lumbar lordosis (21.8%), and reduced thoracic kyphosis with reduced lumbar lordosis (15.5%). Postures involving increased thoracic kyphosis were less common (11.0% overall). Statistically significant sex-related differences were found in thoracic and lumbar angle values (p < 0.01); however, effect sizes were small (d < 0.20). Each posture type was characterised by distinct compensatory features involving pelvic alignment, hip extension strategies, knee alignment, and foot-loading patterns.

Conclusions
The study confirmed a high prevalence of sagittal postural disturbances in children. The most common pattern was reduced thoracic kyphosis, frequently co-occurring with reduced lumbar lordosis. The nine-type classification effectively differentiated postural phenotypes and revealed characteristic multisegmental compensatory mechanisms. Deviations in spinal curvatures were associated with predictable changes in the alignment of the head, shoulders, pelvis, lower limbs, and feet. Although sex-related differences reached statistical significance, their clinical relevance was negligible. The findings underscore the need for a multisegmental approach to postural diagnosis and re-education, and the proposed typology constitutes a useful tool for the early identification of compensatory postural strategies and for planning individualised therapeutic interventions.