In this part of the article on the subject of sideness and dominance of a body side, you will learn how hemispheric dominance affects the preference of the hands, feet and sense of rotation, and what peculiarities there are.
The first part described how laterality develops in the brain hemispheres and that their polarization is an important skill. In order to understand subsequent examinations, it is important to know that the brain hemispheres cross-activate the respective limbs, ie the right brain activates the left arm and vice versa.
The central control of the limbs is thus taken over by the respective brain half. However, in 20-30% of people, the preferred arm is not the stronger one. Only 50-60% of the left-handed and about 75% of the right-handed, the dominant arm is also the stronger.
The following tests can be used to determine handedness:
- Ball throw
- shot put
- Volleyball / tennis serve
- Basketball throw
- table tennis
- Discus throw
The development of postpartum pregnancy is being studied in several studies:
SOVAK (1962) conducted a study on preschool and school children. The original ontogenesis at the first time was 1: 1. By adapting to a right-handed environment, a shift in favor of legal jurisdiction took place at a later date.
Left-handedness = 33.6%
L <R (tendency to the right) = 17%
Right-handedness = 49, 4%
KIRCHERT (1977) found in a longitudinal study that at 16 months there was no ambiguity anymore, but a one-sided preference dominance. In the further child development, the fluctuation is relatively low.
Conclusion: The handedness is primarily subject to the influence of biological maturation factors.
STUTTE / SCHILLING (1975) investigated the connection between power dominance and fine motor training. For this purpose, 110 children were examined at 3 different times with regard to their hand power dominance - 6 months before the start of school, shortly after enrollment and 4 months after starting school. Ambidextre (mutually pronounced) children developed according to the fixed hand to left or right-handed. Thus it has been proven that the writing learning processes in a few months affect the performance lateralization of the hands, if they are carried out consistently.
SIADOW (1982) conducted an investigation in the USSR in children between the ages of 6 and 16 years. Already at 6-year-olds he registered a high proportion of right-handers. This suggests educational influence, because already in preschool age the left-hander share was only 5%. In fact, in Soviet countries, writing was done with the right hand and teachers did everything possible to "correct" left-handedness.
Left-handers with clear / stable sidedness
A left-hander has a mirror-image specialization of the brain hemispheres compared to the right-handed person. Ie. many of the brain's functions, such as language and orientation, lie in a different brain. Some studies assume that this phenomenon is hereditary. It has been shown that a forced habituation of pronounced left-handers not only leads to a re-learning of movement sequences, but also to a reorganization of his entire brain structure.
There is no uniform method for collecting ambidextria. The scientists use different tests, but it is not clear from which degree of a side of an ambidextrice to speak.
SCHILLING (1972) carried out the following study to determine handedness. First, he determined the preferred hand. He had his volunteers do 10 different motor tasks. From the behavior of the hands at the respective achievement the dominance index with r = .89 (probability for the dominance of a hand) was calculated. To then determine the power dominance of a hand, he had a male figure punctured accurately. The correct stitches per time unit were counted. As a result, r = .93 came out. He has proved that procedures with high demands on fine motor coordination are best suited for the identification of left- and right-handers.
The development for the preference of a foot happens largely without educational influences already in the preschool age after the principle of "trial and error". The resulting preference then remains mostly life-long constant.
STERN / SCHILF (1932) says that left-footedness is rather rare in right-handers. 90% of all right-handed people are also "Rechtsfüßer". There is an almost complete concordance (homogeneous laterality). But only 60% of left-handers prefer the left foot. It is an expression for lateralization specifics.
But how does the foot affect the jump in general? The behavior of the preferred and the dominant leg are similar to behavior in handedness. The leg used at the jump does not necessarily have to be the stronger one. For the factor of skill is more important in the determination of Beindominanz than the factor of force. In skill exercises, the stronger leg is considered a mainstay, which in turn is genetically determined.
The following tests can be used to determine footing:
- long jump with start
- "lift jump" over an obstacle
- Hurdles (Abduckfoot)
- High / low start (footprint in front)
- football goal shot (pillar)
The rotation side makes a difference between cornering and turning preference.
WINTER (1953), who devoted himself to flying light aircraft in his spare time, himself confirmed that the left-handers made flying easier. Most circuits also have a link preference. This direction has also established itself in sports when creating stadiums. At the Olympic Games in Athens in 1906, however, this rule was ignored, which has led to confusion among runners. Because the right leg was the stronger in almost all, which favors a run in left turns, but in the right turn can not develop his strength.
For most people, there is a dominant leftward sense of spin with a distribution of 70:30. For women, the legal preference is 15% higher than for men. The reason for the preference for a sense of rotation is the different excitability of the vestibular apparatus and the body symmetry.
The following tests can be used to determine the rotation side
- start - two-legged jump off the trampoline - half or full turn - two-legged landing
- Drop from the box with full turn
- Curve favor when cycling / skiing
How the learning of a movement can transfer from one side to the other (the so-called "crossing effects") and what the page typologies look like in different competitive athletes will be presented in the next part.
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2. Fischer, K. (1992). Laterality and motor skills. Vol. 15: Motorics. Schorndorf: Hoffmann
3. Fischer, K. (1988). Right-left problems in sports and training. Schorndorf: Hoffmann
4. Springer, S .; German, G. (1998). Left - right brain. Heidelberg: Spektrum, Akad. Verlag
5. Thienes, G. (2000). Laterality and sports motor performance. Vol. 23: Motorik. Schorndorf: Hoffmann