Active and passive drag: the role of trunk incline
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The aim of this study was to investigate the role of trunk incline (TI) and projected frontal area (A eff) in determining drag during active/passive measurements. Active drag (D a) was measured in competitive swimmers at speeds from 0.6 to 1.4 m s−1; speed specific drag (D a/v 2 ) was found to decrease as a function of v (P < 0.001) to indicate that the human body becomes more streamlined with increasing speed. Indeed, both A eff and TI were found to decrease with v (P < 0.001) whereas C d (the drag coefficient) was found to be unaffected by v. These data suggest that speed specific drag depend essentially on A eff. Additional data indicate that A eff is larger during front crawl swimming than during passive towing (0.4 vs. 0.24 m2). This suggest that D a/v 2 is larger than D p/v 2 and, at a given speed, that D a is larger than D p.
KeywordsSwimming Hydrodynamic resistance Projected frontal area Drag coefficient
We would like to thank all the swimmers for their patience and kind cooperation and Dr. Fabio Pizzolato for his help in the statistical analysis.
- Arellano R, Terres-Nicol JM, Redondo JM (2006) Fundamental hydrodynamics of swimming propulsion. Rev Port Cien Desp 6:15–20Google Scholar
- Clarys JP (1979) Human morphology and hydrodynamics. In: Terauds J, Bedingfield EW (eds) Swimming III. University Park Press, Baltimore, pp 3–41Google Scholar
- Termin B, Pendergast DR (2001) Training using the stroke frequency-velocity relationship to combine biomechanical and metabolic paradigms. J Swim Res 14:9–17Google Scholar
- Vogel S (1994) Life in moving fluids. Princeton University Press, NJ, pp 81–155Google Scholar
- Vorontsov AR, Rumyantsev VA (2000) Resistive forces in swimming. In: Zatsiorsky VM (ed) Biomechanics in sport: performance enhancement and injury prevention. Blackwell, Oxford, pp 184–204Google Scholar
- Wilson B, Thorp R (2003) Active drag in swimming. In: Chatard JC (ed) Biomechanics and Medicine in Swimming IX. Publications de l’Université de Saint Etienne, Saint Etienne, pp 15–20Google Scholar