title: A Comparison of Experimental and Analytical Procedures to Measure Passive Drag in Human Swimming.
abstract: The aim of this study was to compare the swimming hydrodynamics assessed with experimental and analytical procedures, as well as, to learn about the relative contributions of the friction drag and pressure drag to total passive drag. Sixty young talented swimmers (30 boys and 30 girls with 13.59±0.77 and 12.61±0.07 years-old, respectively) were assessed. Passive drag was assessed with inverse dynamics of the gliding decay speed. The theoretical modeling included a set of analytical procedures based on naval architecture adapted to human swimming. Linear regression models between experimental and analytical procedures showed a high correlation for both passive drag (Dp = 0.777*Df+pr; R2 = 0.90; R2a = 0.90; SEE = 8.528; P<0.001) and passive drag coefficient (CDp = 1.918*CDf+pr; R2 = 0.96; R2a = 0.96; SEE = 0.029; P<0.001). On average the difference between methods was -7.002N (95%CI: -40.480; 26.475) for the passive drag and 0.127 (95%CI: 0.007; 0.247) for the passive drag coefficient. The partial contribution of friction drag and pressure drag to total passive drag was 14.12±9.33% and 85.88±9.33%, respectively. As a conclusion, there is a strong relationship between the passive drag and passive drag coefficient assessed with experimental and analytical procedures. The analytical method is a novel, feasible and valid way to gather insight about one's passive drag during training and competition. Analytical methods can be selected not only to perform race analysis during official competitions but also to monitor the swimmer's status on regular basis during training sessions without disrupting or time-consuming procedures.
authors.affiliation: National Institute of Education, Nanyang Technological University, Singapore, Singapore; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Tiago M
authors.initials: TM
authors.lastname: Barbosa
authors.affiliation: Department of Sport Sciences, Polytechnic Institute of Bragança, Bragança, Portugal; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Morais
authors.affiliation: Department of Sport Sciences, University of Beira Interior, Covilhã, Portugal; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Forte
authors.affiliation: Department of Sport Sciences, University of Beira Interior, Covilhã, Portugal; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Henrique
authors.initials: H
authors.lastname: Neiva
authors.affiliation: Department of Sport Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Nuno D
authors.initials: ND
authors.lastname: Garrido
authors.affiliation: Department of Sport Sciences, University of Beira Interior, Covilhã, Portugal; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Marinho
mesh_terms: D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D005080:Exercise Test / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D016014:Linear Models; D008297:Male; D013550:Swimming / Q000502:physiology*