Dimensions and Design of swimming pool fences and balcony - ANEC

y strong children. Even daily activities become
difficult without enough strength (e.g., older
adults who have lost much of their strength
might have difficulty climbing stairs, being often
at a greater risk of falling).
Muscle strength is related to muscle size or
muscle mass, in particular to physiological
muscle cross-sectional area. However, changes
in strength do not always parallel changes in
muscle size, since other factors, such as
neurological changes over life span, influence
muscle strength (De Ste Croix, 2007; Haywood
& Getchell, 2001). Many factors seem to interact
to produce the expression of strength (see De
Ste Croix, 2007 for a review). Body awareness,
neurological, hormonal, age and sex associated
changes in muscle strength are important during
life span. However, while there is vast literature
focusing on determinants of strength
development, few studies have investigated
common age ranges, muscle groups, testing
protocols and muscle actions, making
comparisons difficult. Despite this lack of
consistency, the age-associated development of
strength is reasonably evident, irrespective of
the muscle group or action under examination.
As children grow older strength increases
steadily (Haywood & Getchell, 2001). Boys and
girls have similar strength levels until they are
about 14 years where it begins to plateau in girls
and a spurt is evident in boys. The exact age in
which sex differences become apparent appears
to be muscle group and muscle action specific.
There is also a suggestion that sex differences
in upper body strength occur earlier than lower
body strength. This has been attributed to the
weight-bearing role of the leg muscles. It has also
been suggested that boys use the upper body
more than girls in their physical activities, such
as climbing (De Ste Croix, 2007).
Davies (1990) tried to determine whether
gender differences could be explained by lean
arm mass and verified that when grip strength
was expressed relative to lean forearm mass no
gender differences were found. This indicates
that strength is greatly related to muscle mass.
2.3.4 Exploring the world
Newborns can only perceive a limited part of
the world. The process that broadens the
perceptual capacity, based upon a set of
biological changes that are essentially driven by
maturation, is called perceptual learning. As all
learning processes, it involves repetitive
exposure to stimulation, and an active organism
that operates in an environment.
It is well known that organisms that have the
chance to develop in enriched environments
develop better and precocious perceptual-motor
skills. Therefore, stimulation is essential for
a correct development. But research has also
demonstrated that passive stimulation is not
enough – growing organisms also demand active
exploration of the world. Fortunately, children
Dimensions and design of swimming pool fences and balcony and stairs barreirs to protect children from falling and from passing through, bellow or above
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