Original Article

European Journal of Applied Physiology

, Volume 90, Issue 3, pp 377-386

Energy balance of human locomotion in water

  • D. PendergastAffiliated withDepartments of Physiology and Mechanical and Aerospace Medicine, University at Buffalo
  • , P. ZamparoAffiliated withDipartimento di Scienze e Tecnologie Biomediche and Microgravity, Ageing, Training, Inactivity (MATI), Centre of Excellence, Università degli Studi di Udine Email author 
  • , P. E. di PramperoAffiliated withDipartimento di Scienze e Tecnologie Biomediche and Microgravity, Ageing, Training, Inactivity (MATI), Centre of Excellence, Università degli Studi di Udine
  • , C. CapelliAffiliated withDipartimento di Scienze e Tecnologie Biomediche and Microgravity, Ageing, Training, Inactivity (MATI), Centre of Excellence, Università degli Studi di Udine
  • , P. CerretelliAffiliated withDipartimento di Scienze e Tecnologie Biomediche, Università degli Studi di Milano
  • , A. TerminAffiliated withDepartments of Physiology and Mechanical and Aerospace Medicine, University at Buffalo
  • , A. CraigJr.Affiliated withDepartment of Physiology, School of Medicine and Dentistry, University of Rochester
  • , D. BushnellAffiliated withDepartments of Physiology and Mechanical and Aerospace Medicine, University at Buffalo
  • , D. PaschkeAffiliated withDepartments of Physiology and Mechanical and Aerospace Medicine, University at Buffalo
    • , J. MollendorfAffiliated withDepartments of Physiology and Mechanical and Aerospace Medicine, University at Buffalo

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Abstract

In this paper a complete energy balance for water locomotion is attempted with the aim of comparing different modes of transport in the aquatic environment (swimming underwater with SCUBA diving equipment, swimming at the surface: leg kicking and front crawl, kayaking and rowing). On the basis of the values of metabolic power (Ė), of the power needed to overcome water resistance ( d) and of propelling efficiency (η P= d/ tot, where tot is the total mechanical power) as reported in the literature for each of these forms of locomotion, the energy cost per unit distance (C=Ė/v, where v is the velocity), the drag (performance) efficiency (η d= d/Ė) and the overall efficiency (η o= tot/Ė=η d P) were calculated. As previously found for human locomotion on land, for a given metabolic power (e.g. 0.5 kW=1.43 l·min−1 O2) the decrease in C (from 0.88 kJ·m−1 in SCUBA diving to 0.22 kJ·m−1 in rowing) is associated with an increase in the speed of locomotion (from 0.6 m·s−1 in SCUBA diving to 2.4 m·s−1 in rowing). At variance with locomotion on land, however, the decrease in C is associated with an increase, rather than a decrease, of the total mechanical work per unit distance (W tot, kJ·m−1). This is made possible by the increase of the overall efficiency of locomotion o= tot/Ė=W tot /C) from the slow speeds (and loads) of swimming to the high speeds (and loads) attainable with hulls and boats (from 0.10 in SCUBA diving to 0.29 in rowing).

Keywords

Economy Efficiency Kayaking Rowing Swimming