Defining Patterns of Sagittal Standing Posture in School-Aged Girls and Boys.

BACKGROUND: Sagittal postural patterns are associated with back pain in adolescents and adults. However, it is unknown if postural patterns are already observable during childhood. This would confirm childhood as a key period for posture differentiation and thus for chronic pain etiology.

OBJECTIVE: We aimed to identify and describe postural patterns in school-aged girls and boys.

DESIGN: This was a cross-sectional study.

METHODS: Eligible children were evaluated at age 7 in the population-based birth cohort Generation XXI, Portugal. Posture was assessed through right-side photographs during habitual standing with retro-reflective markers placed on body landmarks. We defined postural patterns from trunk, lumbar and sway angles using model-based clusters and associations with anthropometric measures were assessed by multinomial logistic regression.

RESULTS: Posture was evaluated in 1147 girls and 1266 boys. Three postural patterns were identified: "Sway" (26.9%), "Flat" (20.9%) and "Neutral to Hyperlordotic" (52.1%) in girls; "Sway to Neutral" (58.8%), "Flat" (36.3%) and "Hyperlordotic" (4.9%) in boys. In girls, higher body mass index was associated with a Sway pattern (vs. Flat, OR=1.21; 95% CI: 1.12-1.29), while in boys, body mass index was higher in the Hyperlordotic pattern (vs. Flat, OR=1.30; 95% CI: 1.17-1.44).

LIMITATIONS: Photogrammetry as a non-invasive method for posture assessment may have introduced some postural misclassification.

CONCLUSIONS: Postural patterns in seven-year-old children were consistent with those previously found in adults, suggesting childhood as a sensitive period for posture differentiation. Sagittal morphology differed between genders, emphasizing gender-specific biomechanical loads during habitual upright position even in prepubertal ages.