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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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WAVELET TRANSFORM ANALYSIS OF ELECTROMYOGRAPHY KUNG FU STRIKES DATA |
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Osmar Pinto Neto1,2,3 
and Ana Carolina de Miranda Marzullo1,2 |
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1Texas A&M University, Department of Health and Kinesiology, College Station, USA, 2Universidade Camilo Castelo Branco São José dos Campos, Brazil, 3Instituto de Pesquisa e Qualidade Acadêmica, São José dos Campos, Brazil.. |
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© Journal of Sports Science and Medicine (2009) 8(CSSI-3), 25 - 28 |
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| ABSTRACT | |||
| In martial arts and contact sports strikes are performed at near
maximum speeds. For that reason, electromyography (EMG) analysis of such
movements is non-trivial. This paper has three main goals: firstly, to investigate
the differences in the EMG activity of muscles during strikes performed
with and without impacts; secondly, to assess the advantages of using Sum
of Significant Power (SSP) values instead of root mean square (rms) values
when analyzing EMG data; and lastly to introduce a new method of calculating
median frequency values using wavelet transforms (WMDF). EMG data of the
deltoid anterior (DA), triceps brachii (TB) and brachioradialis (BR) muscles
were collected from eight Kung Fu practitioners during strikes performed
with and without impacts. SSP results indicated significant higher muscle
activity (p = 0.023) for the strikes with impact. WMDF results, on the other
hand, indicated significant lower values (p = 0. 007) for the strikes with
impact. SSP results presented higher sensitivity than rms to quantify important
signal differences and, at the same time, presented lower inter-subject
coefficient of variations. The result of increase in SSP values and decrease
in WMDF may suggest better synchronization of motor units for the strikes
with impact performed by the experienced Kung Fu practitioners.
Key words: Martial arts, combat sports, Kung Fu, EMG, wavelet transform, impact. |
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