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Welcome to the website of Swimming Human Simulation Model "SWUM"!

Last update : 2014/8/15

What is SWUM?

SWUM (SWimming hUman Model) is a Swimming Human Simulation Model, which has been developed as a powerful analysis tool for various dynamical problems in human swimming. In SWUM, the absolute motion of the whole human body is solved from the equations of motions for the fluid force and the body inertia, by giving the relative body motion (joint angles). SWUM enables you to analyze the various dynamical problems in swimming, such as the effect of difference of the swimming form on the swimming speed and the absolute body motion.

By Whom?

SWUM has been developed by the developer team which is led by Prof. Motomu Nakashima, Tokyo Institute of Technology, Japan.

Analysis Example

Below movies are analysis examples of SWUM for the four modern strokes, which show the motions for one cycle in steady state. The red lines show the fluid force acting on the each part of the body. The water surface is checkered. The total width of the dark and pale blue area corresponds to the stroke length (swimming distance during one cycle). The front crawl, breast, back and butterfly strokes are in order below. (Please use your viewer software's repeat playing function, since the movie is for only one cycle.)

Crawl (MPEG movie, 0.4MB)

Breaststroke (MPEG movie, 0.4MB)

Backstroke (MPEG movie, 0.4MB)

Butterfly stroke (MPEG movie, 0.4MB)

Free Software "Swumsuit" as SWUM's Implementation

A software "Swumsuit" was developed as an implementation of the ideal model SWUM. In addition, Swumsuit enables everyone to perform simulation of the human swimming with easy GUI (Graphical User Interface) operation. Swumsuit is a Free Software based on GPL (GNU General Public License). For the detail of Swumsuit, please see Swimming Human Simulation Software Swumsuit page.

Musculoskeletal Simulation

By Swumsuit version 3.0.0 or higher, you can output files for the musculoskeletal analysis software "AnyBody Modeling System". By using Swumsuit and AnyBody Modeling System, you can conduct the full-body musculoskeletal simulation for swimming. Simulation examples for the four strokes are shown as below.

Crawl (AVI movie, 2.8MB)

Breaststroke (AVI movie, 0.5MB)

Backstroke (AVI movie, 0.6MB)

Buttefly stroke (AVI movie, 0.6MB)

Analysis of Top Swimmer's Underwater Dolphin Kick

The mechanism of the underwater dolphin kick has been analyzed by SWUM. After the analysis of the dolphin kick by a top athlete swimmer, optimizating calculations to maximize the swimming speed and propulsive efficiency were conducted. The details are in the Reference 6 below.

Underwater dolphin kick (MPEG movie, 0.2MB)

Simulation of Dive Start

The dive start has also been simulated by SWUM. For this simulation, a special fluid force which acts on the body during water entry has been introduced to SWUM. The details are in the Reference 7 below.

Dive start (MPEG movie, 0.7MB)

"Multi Agent/Object Simulation"

By Swumsuit 4.0.0 or higher, the "Multi Agent/Object Simulation" has been enabled. "Multi Agent/Object" means multiple swimmers, such as synchronized swimming, and multiple objects with a swimmer, such as equipment in the water. The below examples are monofin swimming (swimmer + monofin), the shooting motion in the water polo, and the lift in the sychronized swimming. The details are in the References 8, 9 and 13 below.

Monofin swimming (MPEG movie, 0.7MB)

Shooting motion in water polo (MPEG movie, 1.1MB)

Lift in synchronized swimming (AVI movie, 2.9MB)

Application to Walking in Water

SWUM has also been applied into the walking in water, which is very effective for rehabilitation. In this analysis, the ground reaction force acts on the foot in addition to the fluid forces. The details are in the Reference 10 and 11 below.

Walking in water (MPEG movie, 0.6MB)

References (in English)

  1. Motomu Nakashima, Ken Satou, Yasufumi Miura, "Development of Swimming Human Simulation Model Considering Rigid Body Dynamics and Unsteady Fluid Force for Whole Body", Journal of Fluid Science and Technology, Vol.2, No.1, pp.56-67 (2007) (Download full paper at the journal's website)
  2. Motomu Nakashima, "Mechanical Study of Standard Six Beat Front Crawl Swimming by Using Swimming Human Simulation Model", Journal of Fluid Science and Technology, Vol.2, No.1, pp.290-301 (2007) (Download full paper at the journal's website)
  3. Motomu Nakashima, "Analysis of Breast, Back and Butterfly Strokes by the Swimming Human Simulation Model SWUM", Biomechanisms of Animals in Swimming and Flying -Fluid Dynamics, Biomimetic Robots, and Sports Science- (Eds. Naomi Kato and Shinji Kamimura), Springer-Verlag, (2007), pp.361-372. (Download manuscript)
  4. Motomu Nakashima, "Development of Computer Simulation Software "Swumsuit" To Analyze Mechanics of Human Swimming", Proceedings of the 2005 International Symposium on Computer Simulation in Biomechanics (ISCSB2005), pp.65-66 (2005) (Download abstract)
  5. Motomu Nakashima and Yugo Motegi, "Development of a Full-Body Musculoskeletal Simulator for Swimming", Proceedings of the 2007 International Symposium on Computer Simulation in Biomechanics (ISCSB2007), pp.59-60 (2007) (Download manuscript)
  6. Motomu Nakashima, "Simulation Analysis of the Effect of Trunk Undulation on Swimming Performance in Underwater Dolphin Kick of Human", Journal of Biomechanical Science and Engineering, Vol.4, No.1, pp.94-104 (2009) (Download full paper at the journal's website)
  7. Hirokazu Kiuchi, Motomu Nakashima, Kuangyou B. Cheng and Mont Hubbard, "Modeling Fluid Forces in the Dive Start of Competitive Swimming", Journal of Biomechanical Science and Engineering, Vol.5, No.4, pp.314-328 (2010) (Download full paper at the journal's website)
  8. Motomu Nakashima, Hirokazu Kiuchi and Kenji Nakajima "Multi Agent/Object Simulation in Human Swimming", Journal of Biomechanical Science and Engineering, Vol.5, No.4, pp.380-387 (2010) (Download full paper at the journal's website)
  9. Motomu Nakashima, Shingo Suzuki and Kenji Nakajima Development of a Simulation Model for Monofin Swimming Journal of Biomechanical Science and Engineering Vol.5, No.4, pp.408-420 (2010) (Download full paper at the journal's website)
  10. Keiko Akiyama, Motomu Nakashima and Issei Ogasawara, Proposal of Walking in Water for ACL Injury Rehabilitation Program by Simulation Journal of Biomechanical Science and Engineering, Vol.5, No.4 (2010), pp.461-471 (Download full paper at the journal's website)
  11. Keiko AKIYAMA, Motomu NAKASHIMA and Tasuku MIYOSHI, "Simulation Analysis of the Mechanical Body Load during Walking in Water", Journal of Environment and Engineering, Vol.6, No.2 (2011), pp.365-375. (Download full paper at the journal's website)
  12. Motomu Nakashima, Modeling and Simulation of Human Swimming, Journal of Aero Aqua Bio-mechanisms, Vol.1, No.1, pp.11-17 (2010) (Download full paper at the journal's website)
  13. Motomu Nakashima, Go Hatakeyama, Miwako Homma and Koji Iti, Simulation Analysis of Lift in Synchronized Swimming, Journal of Aero Aqua Bio-mechanisms Vol.3, No.1, pp.51-56 (2013) (Download full paper at the journal's website)

Contact

Please feel free to contact us about SWUM to the mail address: swum-admin_at_swum.org (Please change "_at_" into "@").

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