AUTHOR=Barbosa Tiago M. , Goh Wan X. , Morais Jorge E. , Costa Mário J. , Pendergast David 

TITLE=Comparison of Classical Kinematics, Entropy, and Fractal Properties As Measures of Complexity of the Motor System in Swimming

JOURNAL=Frontiers in Psychology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2016.01566

DOI=10.3389/fpsyg.2016.01566

ISSN=1664-1078

ABSTRACT=<p>The aim of this study was to compare the non-linear properties of the four competitive swim strokes. Sixty-eight swimmers performed a set of maximal 4 × 25 m using the four competitive swim strokes. The hip's speed-data as a function of time was collected with a speedo-meter. The speed fluctuation (<italic>dv</italic>), approximate entropy (<italic>ApEn</italic>) and the fractal dimension by Higuchi's method (<italic>D</italic>) were computed. Swimming data exhibited non-linear properties that were different among the four strokes (14.048 ≤ <italic>dv</italic> ≤ 39.722; 0.682 ≤ <italic>ApEn</italic> ≤ 1.025; 1.823 ≤ <italic>D</italic> ≤ 1.919). The <italic>ApEn</italic> showed the lowest value for front-crawl, followed by breaststroke, butterfly, and backstroke (<italic>P</italic> &lt; 0.001). Fractal dimension and <italic>dv</italic> had the lowest values for front-crawl and backstroke, followed by butterfly and breaststroke (<italic>P</italic> &lt; 0.001). It can be concluded that swimming data exhibits non-linear properties, which are different among the four competitive swimming strokes.</p>