Purpose: This study examined the effect of exercise training on prepubertal
children's (ET, N = 28) lipid-lipoprotein profile, relative to a maturity
matched control group (CON, N = 20). Methods: Training for ET involved stat
ionary cycling for 30 min, 3 times.wk(-1) for 12 wk, at 79.3 +/- 1.2% (mean
+/- SD) peak heart rate (HR). Controls maintained their usual lifestyle pa
ttern. Plasma concentrations of total triacylglycerol (TG), total cholester
ol (TC), and high-density lipoprotein (HDL)-cholesrerol (HDL-C) were determ
ined pre- and postintervention. Low-density lipoprotein (LDL)- cholesterol
(LDL-C) was subsequently estimated from these concentrations, and the ratio
s TC/HDL-C and LDL-C/HDL-C were also calculated. There were no pretest diff
erences (P > 0.05) for any of these blood analytes between groups. The foll
owing, potentially, confounding variables were also measured: peak (V) over
dot O-2 percent body fat (%BF), dietary composition, and habitual physical
activity. These variables, with pretest HDL-C, were included as covariates
in two-way split plot ANCOVA analyses. Dietary variables were not included
as covariates as they were not related to any of the blood analytes. Resul
ts: There were no differences over time or between groups for TG and TC (P
> 0.05). LDL-C decreased in ET (-10.2%) but remained unchanged in CON (0.3%
) over the intervention period (P < 0.05). HDL-C increased in ET (9.3%) but
decreased in CON (-8.9%) (P < 0.01). A similar, but inverted, pattern of c
hange (P < 0.01) was revealed for both ratios, TC/HDL-C (-11.6% vs 6.3%, ET
and CON, respectively), and LDL-C/HDL-C (-17.2% vs 8.0%, ET and CON, respe
ctively). The favorable alterations in the lipid-lipoprotein profile for ET
were independent of alterations in peak (V) over dot O-2, (group X time in
teraction, P < 0.05), %BF (main effect time, P < 0.01), and habitual physic
al activity (group X time interaction, P < 0.01). Conclusions: In conclusio
n, the favorable alterations in the lipoprotein profile seen in this study
would suggest that it is possible to influence the prepubertal lipoprotein
profile independent of alterations in confounding variables such as body co
mposition, cardiorespiratory fitness, and habitual physical activity.