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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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COMPARISON OF TWO VARIANTS OF A KATA TECHNIQUE (UNSU): THE NEUROMECHANICAL POINT OF VIEW |
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Valentina Camomilla1  ,
Paola Sbriccoli1, Alberto Di Mario2, Alessandro Arpante1
and Francesco Felici1 |
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1Department of Human Movement and Sport Sciences, University of Rome, Italy. 2FIJLKAM - National Judo, Karate, Wrestling and Martial Arts Federation, Roma, Italy. |
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© Journal of Sports Science and Medicine (2009) 8(CSSI-3), 29 - 35 |
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| ABSTRACT | |||
| The objective of this work was to characterize from a neuromechanical
point of view a jump performed within the sequence of Kata Unsu in International
top level karateka. A modified jumping technique was proposed to improve
the already acquired technique. The neuromechanical evaluation, paralleled
by a refereeing judgment, was then used to compare modified and classic
technique to test if the modification could lead to a better performance
capacity, e.g. a higher score during an official competition. To this purpose,
four high ranked karateka were recruited and instructed to perform the two
jumps. Surface electromyographic signals were recorded in a bipolar mode
from the vastus lateralis, rectus femoris, biceps femoris, gluteus maximus,
and gastrocnemious muscles of both lower limbs. Mechanical data were collected
by means of a stereophotogrammetric system and force platforms. Performance
was associated to parameters characterizing the initial conditions of the
aerial phase and to the CoM maximal height. The most critical elements having
a negative influence on the arbitral evaluation were associated to quantitative
error indicators. 3D reconstruction of the movement and videos were used
to obtain the referee scores. The Unsu jump was divided into five phases
(preparation, take off, ascending flight, descending flight, and landing)
and the critical elements were highlighted. When comparing the techniques,
no difference was found in the pattern of sEMG activation of the throwing
leg muscles, while the push leg showed an earlier activation of RF and GA
muscles at the beginning of the modified technique. The only significant
improvement associated with the modified technique was evidenced at the
beginning of the aerial phase, while there was no significant improvement
of the referee score. Nevertheless, the proposed neuromechanical analysis,
finalized to correlate technique features with the core performance indicators,
is new in the field and is a promising tool to perform further analyses. Key words: Biomechanics, electromyography, technique analysis, karate. |
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