Comparison of young swimmer’s active drag coefficient using three methods to compute trunk transverse surface area.

• Autor(a) principal: Morais, Jorge
• Data de Publicação: 2012
• Outros Autores: Costa, Mário, Moreira, Marc, Barbosa, Tiago
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10314/3294

The purpose of this study was to compare the active drag coefficient (CDa) of young swimmers using three different ways of measuring the trunk transverse surface area (TTSA). 23 young swimmers, including 12 boys and 11 girls were analyzed. The velocity perturbation method of Kolmogorov was used to compute CDa. The TTSA was calculated based on three methods: (i) measured by photogrammetric; (ii) estimated by the equation developed by Clarys and; (iii) estimated from the equations developed by Morais et al.. Three procedures were used in the comparison CDa values: (i) T-Student test; (ii) simple linear regression analysis and; (iii) Bland Altman plots. All paired samples showed significant differences (p <0.001) when comparing mean values. However, there were significant correlations (p <0.001) between the paired samples in the simple linear regression analysis, and the in the Bland Altman plots for all conditions studied. At least 80% of the plots were within the ± 1.96 standard deviation of the difference. As a conclusion, the mean values of CDa computed with TTSA estimated with the equations developed by Morais et al. were the ones with lower difference compared with TTSA measured directly. Those should be used by coaches and investigators in order to estimate TTSA for CDa computing.