PEDOMETER DETERMINED PHYSICAL ACTIVITY, BONE MINERAL CONTENT AND DENSITY OF PREMENARCHEAL GIRLS Kambas, A., Leontsini, D., Chatzinikolaou, A., Avloniti, A., Stambouis, Th., Gounelas, G., School of Physical Education and Sport Science, Democritus

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PEDOMETER DETERMINED PHYSICAL ACTIVITY, BONE
MINERAL CONTENT AND DENSITY OF PREMENARCHEAL
GIRLSKambas, A., Leontsini, D., Chatzinikolaou,
A., Avloniti, A., Stambouis, Th., Gounelas, G.,
School of Physical Education and Sport Science,
Democritus University of Thrace, Komotini, Greece
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Introduction Childhood is a unique period of
human life due to the rapid growth rates and the
special needs that exists. Children have much
higher nutrient requirements compared to adult
and exhibit high growth rates of bone tissue,
making this stage of life important for improving
bones condition and increase peak bone mass as
a factor that can compensate osteoporosis and
bone fractures (Hind Burrows, 2007). Increased
physical activity (PA) increases bone density and
composition in children of school age in hole
body, lumbar spine and femoral neck bone area
(Meyer et al, 2011), promoting bone health and
preventing osteoporosis later in
life (Baxter-Jones et. al., 2008). However,
current literature lacks comprehensive data on
physical activity's contribution to bone Mineral
content and density in prepubescent girls.

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Methods The sample consists of 60 girls (means
SD), age 11.00.93 yr, Weight 36.529.7kg.,
height 1.44.07cm. PA was assessed using the
piezoelectric Omron Walking style pro HJ-720IT-E2
pedometer worn for 10 consecutive
days.
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Bone mineral content and density parameters
wer measured with dual-energy densitometry (Lunar
DPX NT). A one-way Anova with adjustment for
weight was conducted to check the effects of PA
on bone parameters. A Sidak test was applied for
post-hoc comparisons.
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Results A visual-binning procedure was used to
classify step counts into categories, resulting
three groups (low 5,800-8,531 steps/day mod
8,561-16,000 steps/day and high 17,460-21,094
steps/day). Results revealed significant effects
of PA on BMDLS (F7.17, plt.005), BMDHIP (F8.19,
plt.001), BMDNECK (F5.87, plt.005), BMDTRO
(F7.45, P,.001) and BMDWARD (F13.38, plt.001).
Post-hoc tests showed that in all comparisons the
"high" PA group demonstrated better values than
the other two groups (plt.005).
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Results
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Discussion or/and Conclusions A great determinant
of BMD in girls is puberty (Annemieke et.al.
1997), and physical activity appears to be an
important determinant too. The results of this
study suggest that PA (steps/day) might affect
bone mineral content and density in LS, HIP,
NECK, and TRO areas. More specifically, it
appears that prepubertal girls demonstrating more
than 17,000 steps/day benefited more than their
counterparts with less of 16,000 steps/day. These
differences were translated to higher bone
strength. Nevertheless there is a need to
translate steps-data in order to determine their
relationship to PA intensity.
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References or Conclusions Annemieke M. Boot,
Maria A. J. de Ridder, Huibert A. P. Pols, et.
al. (1997). Bone Mineral Density in Children and
Adolescents Relation to Puberty, Calcium Intake,
and Physical Activity. The Journal of Clinical
Endocrinology Metabolism, DOI
http//dx.doi.org/10.1210/jcem.82.1.3665. Baxter-J
ones ADG, Kontulainen SA, Faulkner RA, et al.
(2008). A longitudinal study of the relationship
of physical activity to bone mineral accrual from
adolescent to young adulthood. Bone,
431101-7. Hind K. Burrows M. (2007).
Weight-bearing exercise and bone mineral accrual
in children and adolescents A review of
controlled trials. Bone, 40, 14-27. Meyer, U.,
Romann, M., Zahner, L., Schindler, C., Puder,
J.J., Kraenzlin, M., Rizzoli, R. Kriemler, S.
(2011). Effect of a general school-based physical
activity intervention on bone mineral content and
density a cluster-randomized controlled trial.
Bone, 48, 792-797.  Contact akampas_at_phyed.duth.gr