Ortopedická protetika Praha sro - Společnost pro pojivové tkáně

The points T2 and T7 are characteristics of
maximum acceleration of growth velocity
in a given spurt, while the points T4 and T9
determine its maximum deceleration. The
points T5 and T10 representing a return to
minimum growth velocity before a given
spurt are not determined by this model.
The presence of single points is given by
the individual growth dynamics of a given
parameter (Figure 1).
When comparative figures are constructed,
the first indispensable step to do
consists in transposing parameters measured
in different units into scales that enable
their mutual comparison. As an optimal
solution it was necessary to chose the
so-called ‘method of standardisation’,
which is based on calculating the quotient
of differences between obtained mathematical
quantities. Their mutual relation is
expressed by the following equation:
x 0→1 = (y der – y min )
(y max – y min )
If x is a positive number ranging in the
interval from 0 to 1, y der is the derivative of
the average value of the marker measured
in a given age category, y min is the minimal
value of a given marker on the whole
scale of the sample observed and y max is
its the corresponding maximal value. This
method makes it possible to carry out an
objective unbiased comparison of seemingly
incomparable somatic markers that
are correlated by deeper growth correspondences
(2, 3).
RESULTS
The development of features with an
even well-balanced growth dynamics:
176
Body height – Boys
(Table 2a, Figure 2a)
The beginning of the MGS of body
height in boys was found at the average
age of 7.2 years (T1), the culminating peak
phase was recorded at the age of 7.9 years
(T3). MGS was finished in the year 9.0 of
age (T4), with the average time of duration
amounting to 1.8 year. After the deceleration
phase of MGS we could observe
a marked decline of growth velocity until
the beginning of PS in the year 10.1 of age
(T6). On average most boys reached the
peak of pubertal growth velocity (T8) at
the age of 13.3 years (7.6 cm/year), i.e. the
year 1.4 after the age of maximal acceleration
of body height (T7). The period
of the acceleration phase of PS lasted 3.2
years with an average height increment
amounting to 20.3 cm. Owing to the age
structure of our sample of children it was
not possible to record the point of maximal
deceleration of growth velocity (T9)
in the period of PS in boys.
Body height – Girls
(Table 2b, Figure 2b)
Owing to the age composition of our
sample and an earlier start of MGS, our
study does not record the beginning of the
MGS of body height. The culminating peak
of growth velocity of MGS (T3) lay in the
same age as in boys (the year 7.2 of age). The
duration of the deceleration phase of MGS
and the further decrease of growth velocity
in girls until the beginning of PS (T6–T3)
was more than 1 year shorter than in boys.
The PS of body height began in the year 8.5
of age (T6) with the culminating peak at the
year 11.2 of age (T8) (average growth velocity
amounting to 6.6 cm/year). The highest
LOCOMOTOR SYSTEM vol. 14, 2007, No. 3+4