Developmental Changes Of Left Ventricular Mass During Pubertal Years Using Static And Ontogenetic Allometric Exponents In Boys Aged 11-14 Years

Purpose: Using static, ontogenetic and multilevel allometric modelling, objectives of the study were twofold: to estimate inter- and intra-individual effects of body size descriptors on the development of LVM in adolescent boys, and to examine independent and combined effects of physical activity (PA), sedentary time and biological maturity status on the development of LVM.

Methods: 110 boys (11-14 years at baseline) were assessed biannually for 2 years. Stature and body mass were measured. Fat mass (FM) and fat-free mass (FFM) were estimated from skinfolds. Somatic maturation was estimated as current stature expressed as a percentage of predicted mature height using the equation of Khamis & Roche. PA was measured with an ActiGraph GT1M accelerometer for seven consecutive days. LVM was obtained from M-mode echocardiograms using two-dimensional images.

Results: Inter-individual allometric coefficients for stature did not exceed k=2.4 at most ages, while intra-individual coefficients varied considerably (k’=0.24-9.73). The longitudinal allometric coefficient for stature was k1 = 0.74. The multilevel allometric model suggested that a gain of 10 cm in stature predicted 21 g of LVM. Once ln-stature was controlled, significant independent effects of ln-FM (k2 =0.07, antilog: 1 kg predicts 1.069 g of LVM), ln-FFM (k3 = 0.323, antilog: 1 kg predicts 1.381 g of LVM), CA (b = 0.028) and maturity status [∆a=0.01 (on time vs late) and ∆a a=0.04 (early vs late)] were noted. Although small associations with LVM (P < 0.05), sedentary time (r = +0.13), light PA (r =-0.17) and MVPA (r =-0.10) were not significant longitudinal predictors.

Conclusions: Results suggest an important role for individual differences in allometric growth of body size dimensions and biological maturation in understanding the growth of LVM in adolescent males.