Sports Engineering

, Volume 18, Issue 3, pp 149–156 | Cite as

Use of pressure distribution analysis to estimate fluid forces around a foot during breaststroke kicking

  • Takaaki Tsunokawa
  • Motomu Nakashima
  • Hideki Takagi
Original Article


The aims of this study were twofold: first, use a robotic leg to investigate the reliability of estimating fluid forces acting on the foot during breaststroke kicking and second, test the utility for actual human swimmer’s kicking. In this study, fluid forces were estimated from the measurement of pressure distribution around a foot. In the first experiment, the reliability of the estimated measurements was evaluated in a series of experiments using a robotic leg that can reproduce breaststroke-kicking motions. The resulting estimates correlated significantly with the fluid force acting on the foot model that was measured by a load cell (r = 0.62−0.92). In the second experiment, breaststroke-kicking motions of human swimmers were analyzed using the methodology tested in the first experiment. The estimated fluid forces showed significant correlation with the velocities of the human swimmers (r = 0.87). Furthermore, this methodology can monitor intra-cycle force fluctuations. We conclude that the present methodology can be used to evaluate breaststroke-kicking motions quantitatively, thereby assisting swimmers and their coaches in better understanding of breaststroke kicking.


Swimming Hydrodynamic force Direct measurement Swimming robot 


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Copyright information

© International Sports Engineering Association 2015

Authors and Affiliations

  • Takaaki Tsunokawa
    • 1
  • Motomu Nakashima
    • 2
  • Hideki Takagi
    • 1
  1. 1.Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaJapan
  2. 2.Department of Mechanical and Control EngineeringTokyo Institute of TechnologyTokyoJapan

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