title: Comparison of Classical Kinematics, Entropy, and Fractal Properties As Measures of Complexity of the Motor System in Swimming.
abstract: 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 (dv), approximate entropy (ApEn) and the fractal dimension by Higuchi's method (D) were computed. Swimming data exhibited non-linear properties that were different among the four strokes (14.048 ≤dv≤ 39.722; 0.682 ≤ApEn≤ 1.025; 1.823 ≤D≤ 1.919). TheApEnshowed the lowest value for front-crawl, followed by breaststroke, butterfly, and backstroke (P< 0.001). Fractal dimension anddvhad the lowest values for front-crawl and backstroke, followed by butterfly and breaststroke (P< 0.001). It can be concluded that swimming data exhibits non-linear properties, which are different among the four competitive swimming strokes.
authors: Physical Education and Sport Science Academic Group, Nanyang Technological UniversitySingapore, Singapore; CIDESD - Research Centre in Sports, Health and Human DevelopmentVila Real, Portugal.
authors: Tiago M
authors: TM
authors: Barbosa
authors: Physical Education and Sport Science Academic Group, Nanyang Technological University Singapore, Singapore.
authors: Wan X
authors: WX
authors: Goh
authors: CIDESD - Research Centre in Sports, Health and Human DevelopmentVila Real, Portugal; Department of Sport Science, Polytechnic Institute of BragançaBragança, Portugal.
authors: Jorge E
authors: JE
authors: Morais
authors: CIDESD - Research Centre in Sports, Health and Human DevelopmentVila Real, Portugal; Department of Sport Science, Polytechnic Institute of GuardaGuarda, Portugal.
authors: Mário J
authors: MJ
authors: Costa
authors: Department of Physiology and Biophysics, University at Buffalo New York, NY, USA.
authors: David
authors: D
authors: Pendergast
keywords: complexity; human movement; non-linear parameters; predictability; swimming; variability