Gender differences in sagittal standing alignment before pubertal peak growth: the importance of subclassification and implications for spinopelvic loading

Abstract

The aim of this study was to analyze gender differences in sagittal standing alignment at pre-peak height velocity age thereby applying a scientifically sound and practically oriented classification scheme for overall standing balance. The study population consisted of healthy boys (n = 639) and girls (n = 557) before pubertal peak growth. During subjects' habitual standing, sagittal plane measures of the spine, pelvis and lower limbs were collected using a clinical screening protocol. With each subject classified as one of three postural types (neutral, sway-back, or leaning-forward), differences in sagittal plane alignment were analyzed between sexes. The results revealed clear differences between genders in each of the postural types. Within the neutral and sway-back postural subgroups, boys presented more forward inclination of the trunk, more thoracic kyphosis and more pelvis backtilt compared with girls. Within the leaning-forward category, girls displayed more forward trunk lean, less thoracic kyphosis and more pelvic anteversion. A state of lumbar segmental hyperextension appeared to exist in female leaning-forward subjects. Our results reveal for the first time that sagittal standing alignment is different between prepubescent boys and girls when subjects are appropriately subclassified, and conversely represent a 'wash-out effect' when pooled. When the classification system is applied, gender-specificity in gravity line position is suggested, implying gender-related differences in lever arms and thus load. Present findings may add to our understanding of gender-specific biomechanical challenges posed by habitual posture, and may shed new light on sagittal standing alignment as a possible contributory factor in developmental spinal-pelvic disorders.

Multivariable modeling of factors associated with spinal pain in young adolescence

“…To determine the proportion of trunk length to body length, sitting height was measured [64]. Habitual standing posture in the sagittal plane was quantified as described previously [56,64]. More specifically, data were collected regarding gross body segment orientations (i.e., trunk lean, body lean, and anteroposition of the head), specific spinopelvic characteristics (i.e., pelvic orientation (pelvic tilt, sacral inclination), spinopelvic extensiveness parameters (number of vertebrae included in the thoracic kyphosis and lumbar lordosis, vertebral level of the thoracic apex, lumbar apex, and intercristal line), magnitude of spinal curves (thoracic kyphosis, lumbar lordosis) and knee alignment.…”

Posture class prediction of pre-peak height velocity subjects according to gross body segment orientations using linear discriminant analysis

“…Nonetheless, this latter finding did not reach statistical significance [15]. Further support for the categorizing system proposed by Dolphens et al [15,16] was derived from the finding thatfor the first time-clinically relevant sex differences in sagittal standing posture features were established at pre-PHV age [16,17]. Generally, these differences in spinopelvic, lower limb and entire body alignment between genders were concealed by examining an aggregate pre-PHV population [13,14], and turned up only when the classification was applied.…”

“…A second limitation of the present research paper might involve the use of cluster analysis results [15,16] as the gold standard, which implies that good performance of the postural classification model refers to good prediction of the classification obtained via cluster analysis. Nevertheless, the analytical method presented here enables an objective class allocation into a scientifically sound and practically oriented classification scheme that proved both clinically meaningful and relevant [15][16][17].…”

“…The adolescent growth spurt, in particular, is considered a critical period for musculoskeletal development [4,8,9,12]. Hence, a paradigm shift in research on sagittal plane posture and its clinical relevance has been proposed concentrating on young adolescent populations, thereby taking biologicalrather than chronological-age as a baseline for recruitment and comparisons [13][14][15][16][17]. In this regard, it is important to realize that both age at takeoff (i.e., the onset of growth acceleration) and peak height velocity (PHV) are sexdependent with these parameters occurring, on average, about 2 years earlier in girls than boys [18].…”

Pradinių klasių moksleivių fizinių ypatybių vertinimas

“…(14). O kitame straipsnyje -priešingai -didesnį krūtininės kifozės pasikartojimą turėjo berniukai (15).…”