Ortopedická protetika Praha sro - Společnost pro pojivové tkáně

increment of body height was recorded in
the acceleration phase of PS (16.3 cm). Girls
reached the point of maximal growth velocity
deceleration in PS (T9) 2.6 years later at
the average age of 13.8 years.
Intersexual difference
The height in MGS and its development
on the average velocity growth curve of
body height seem to be almost equal in
both sexes. Its start and end is, however,
earlier in girls and a similar development
is observed also in PS. The deceleration
phase of MGS in girls is shorter and softer
than in boys. Girls do not tackle such
a dramatic decline of growth velocity and
confirm the well-known trend determining
that the deceleration phase of MGS
in girls is almost immediately followed by
the acceleration phase of PS. Boys undergo
a much more marked decrease of growth
velocity after the period of MGS, their average
increments at the point T6 sink to the
lowest minimum in the period of whole
childhood. The beginning of the pubertal
spurt of body height therefore starts
1.5 year later than in girls. The average
intersexual difference of their peak height
velocity (T8) amounts to 2 years. In the PS
boys generally undergo a more intensive
growth with a longer term of duration.
Girls reached lower average values of growth
velocity and their velocity curve was less
steep in the acceleration phase as well as
deceleration phase of PS.
Sitting height – Boys
(Table 3a, Figure 3a)
In the MGS the growth acceleration of
sitting height precedes the acceleration of
body height by 0.7 years. The intensity of
growth spurt is weaker, its average growth
velocity at the peak of MGS (T3) is twice as
lower than that in body height. The deceleration
phase of the MGS in sitting height is
slower, it brings a temporary compensation
of trends in the development of the growth
velocity of both parameters, which is manifested
in reaching the minimal growth velocity
at almost the same age before PS (T6).
The start of pubertal acceleration therefore
displays a simultaneous progress at the age
of 10 years, but the dynamics of PS is different.
The average increments of the growth
velocity of sitting height are proportionally
lower than in body height, but the acceleration
phase of PS shows a considerably
longer period of duration. During the PS
(T8) most boys reach the peak growth velocity
of sitting height towards 14 of age, i.e.
more than 0.6 year after the pubertal peak
of their body height.
Sitting height – Girls
(Table 3b, Figure 3b)
The development of growth velocity in
the MGS in girls bears much similarity to
the tendencies observed in boys. However,
the deceleration phase of MGS is steep and
shorter here, the point of minimal growth
velocity before PS is reached earlier than in
boys (T6 = 8.7 years). This trend is fully in
accord with the development of the growth
velocity of body height, because the age of
the start of PS of sitting height is in relative
correspondence with the beginning of the
PS of body height. It also represents an
almost fluent continuation of the deceleration
of MGS without a previous marked
decrease of growth velocity. The PS of
sitting height exhibits a steep acceleration
phase and on average it reaches the peak
growth velocity 0.7 year later after the peak
POHYBOVÉ ÚSTROJÍ, ročník 14, 2007, č. 3+4 179