2013, Volume 9, Issue 3

The effect of expertise in karate on postural control in quiet standing

Grzegorz Juras1, Marian Rzepko2, Paweł Król2, Wojciech Czarny2, Wojciech Bajorek2, Kajetan Słomka1, Grzegorz Sobota1

1Department of Motor Behavior, Academy of Physical Education, Katowice, Poland
2Department of Physical Education, University of Rzeszów, Rzeszów, Poland

Author for correspondence: Grzegorz Juras; Department of Motor Behavior, Academy of Physical Education, Katowice, Poland; email: g.juras[at]awf.katowice.pl

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Background and Study Aim: Balance ability plays and important role in daily activities. A general opinion that in the sports performance high level of balance is even more desirable is common. However, there are limited data on the influence of balance training on sport performance in elite athletes. We aimed to investigate the effect of expertise on the static balance in elite karate practitioners and determination of the value of COP trajectory decomposition as a useful tool in describing quiet standing in karate experts.
Material and Methods: Nine elite karate athletes (24.6 years ± 4.8) and eleven PE students participated voluntarily in the experiment. A force platform (AMTI, Accugait, USA), with a sampling frequency set at 50 Hz was used to measure the static balance. Subjects performed 2 trials of quiet standing with eyes open and eyes closed. Subjects were instructed to stand barefoot in a comfortable foot position with their arms along their sides and with their gaze pointed straight ahead. The duration of each trial was 30 s, during which subject was asked not to shift theirbody weight. Stabilographic signal was processed with the use of standard and a relatively new method of stabilogram decomposition, proposed by Zatsiorsky and Duarte (1999).
Results: There was a significant main effect of expertise in both directions A/P and M/L (Wilks’ Lambda = 0.0958; F = 44.8479; p < 0.0001 in A/P and Wilks’ Lambda = 0.0256; F = 34.2630; p < 0.0001 in M/L) (ANOVA). Post hoc comparisons using the Tukey HSD test indicated that the mean score for path length of COP, rambling and trembling displacement differs in karate and the control group (increased mean values of basic parameter which was a COP path length). Highly trained group of elite karate athletes was characterized by increased values of path length of COP and rambling / trembling trajectories. Results of Mann-Whiney U test shows that there were NOT significant differences in the group of elite athletes during trials conducted with eyes closed (p>0.05).
Conclusions: Practicing karate results in long term changes in postural control. The effect of expertise on the static balance in examined elite karate practitioners was observed in increasing of the body sway. We assumed that it was caused by the redundancy of the sensorimotor system.

Key words: body balance, elite athletes, martial arts, rambling decomposition of cop, trembling decomposition of cop