Journal of Human Sport and Exercise

A model for active drag force exogenous variables in young swimmers

Tiago M. Barbosa, Mário J. Costa, Mário C. Marques, António J. Silva, Daniel A. Marinho



The aim of the current study was to develop a structural equation modeling (i.e., path-flow analysis model) for active drag force based on anthropometric, hydrodynamic and biomechanical variables in young swimmers. The theoretical model was developed according to main review papers about these determinants. Sixteen male swimmers (12.50±0.51 years-old; Tanner stages' 1-2) were evaluated. It was assessed: (i) anthropometrical variables such as body mass, height, frontal surface area; (ii) hydrodynamic variables including drag coefficient and active drag with the velocity perturbation method; (iii) the biomechanical variables stroke length, stroke frequency and swimming velocity after a maximal 25-m bout. Path-flow analysis was performed with the estimation of linear regression standardized coefficients between exogenous and endogenous variables. To verify the model fit, root mean square residual was computed. The active drag presented significant association with all exogenous variables, except for stroke length and stroke frequency. Confirmatory model excluded the frontal surface area (RMSR>0.1). Even so, 95% of active drag was explained by remaining variables in the model. Confirmatory path-flow model can be considered as not suitable of the theory. In order to increase the model fit, in a near future it is advice to develop new frontal surface area estimation equations specific for young swimmers rather than using models developed with adult/elite swimmers.


Aged-Groups; Biomechanics; Anthropometrics; Hydrodynamics


Arellano, R., Pardillo, S., Gavilan, A. Usefulness of the Strouhal number in evaluating human under-water undulatory swimming. In: JC Chatard (ed.). Biomechanics and Medicine in Swimming IX. University of Saint-Etienne: Saint-Etienne; 2003, pp. 33-38.

Barbosa, T.M., Bragada, J.A., Reis, V.M., Marinho, D.A., Carvalho, C., Silva, A.J. Energetics and biomechanics as determining factors of swimming performance: updating the state of the art. J Sci Med Sports. 2010a; 13: 262-269.

Barbosa, T.M., Costa, M.J., Marinho, D.A., Coelho, J., Moreira, M., Silva, A.J. Modeling the links between age-group swimming performance, energetic and biomechanic profiles. Ped Exerc Sci. 2010b; 22:379-391.

Barbosa, T.M., Fernanes, R.J., Keskinen, K.L., Colaço, P., Cardoso, C., Silva, J., Vilas-Boas, J.P. Evaluation of the energy expenditure in competitive swimming strokes. Int J Sports Med. 2006; 27: 894-899.

Clarys, J.P. Human morphology and hydrodynamics. In: Terauds J and Bedingfield EW (Eds). Swimming III. University Park Press: Baltimore; 1979, pp. 3-41.

Craig, A., Pendergast, D. Relationships of stroke rate, distance per stroke and velocity in competitive swimming. Med Sci Sports Exerc. 1979; 11:278-283.

Grimston, S.K., Hay, J. Relationship among anthropometric and stroking characteristics of college swimmers. Med Sci Sports Exerc. 1986; 18:60-68.

Huijing, P., Toussaint, H.B., Mackay, R., Vervoon, K., Clarys, J., Hollander, A.P. Active drag related to body dimensions. In: B Ungerechts, K Wilke, K Reischle (Eds). Swimming Science V. Human Kinetics Books: Champaign, Illinois; 1988, pp. 31-37.

Kjendlie, P.L., Stallman, R.K. Drag characteristics of competitive swimming children and adults. J Appl Biomech. 2008; 24:35-42.

Kolmogorov, S.V., Duplisheva, A. Active drag, useful mechanical power output and hydrodynamic force coefficient in different swimming strokes at maximal velocity. J Biomech. 1992; 25:311-318.

Lavoie, J.M., Montpetit, R. Applied Physiology of swimming. Sports Med. 1986; 3:165-188.

Marinho, D.A., Barbosa, T.M., Costa, M.J., Figueiredo, C., Reis, V.M., Silva, A.J., Marques, M.C. Can 8-weeks of training affect active drag in young swimmers? J Sports Sci Med. 2010; 9:71-78.

Schidt, A., & Ungerechts, B.E. The effect of cognitive intervention on stroke distance in age-group swimmers. In: T Nomura, BE Ungerechts (Eds.). The Book of Proceedings of the 1st International Scientific Conference of Aquatic Space Activities. University of Tskuba: Tsubuka; 2008, pp. 380-387.

Silva, A.J., Costa, A.M., Oliveira, P.M., Reis, V.M., Saavedra, J., Perl, J., Rouboa, A., Marinho, D.A. The use of neural network technology to model swimming performance. J Sports Sci Med. 2007; 6:117-125.

Tousssaint, H., Roos, P., Kolmogorov, S. The determination of drag in front crawl swimming. J Biomech. 2004; 37:1655-1663.


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