title: Young swimmers' classification based on kinematics, hydrodynamics, and anthropometrics.
abstract: The aim of this article has been to classify swimmers based on kinematics, hydrodynamics, and anthropometrics. Sixty-seven young swimmers made a maximal 25 m front-crawl to measure with a speedometer the swimming velocity (v), speed-fluctuation (dv) and dv normalized to v (dv/v). Another two 25 m bouts with and without carrying a perturbation device were made to estimate active drag coefficient (CDa). Trunk transverse surface area (S) was measured with photogrammetric technique on land and in the hydrodynamic position. Cluster 1 was related to swimmers with a high speed fluctuation (ie, dv and dv/v), cluster 2 with anthropometrics (ie, S) and cluster 3 with a high hydrodynamic profile (ie, CDa). The variable that seems to discriminate better the clusters was the dv/v (F=53.680; P<.001), followed by the dv (F=28.506; P<.001), CDa (F=21.025; P<.001), S (F=6.297; P<.01) and v (F=5.375; P=.01). Stepwise discriminant analysis extracted 2 functions: Function 1 was mainly defined by dv/v and S (74.3% of variance), whereas function 2 was mainly defined by CDa (25.7% of variance). It can be concluded that kinematics, hydrodynamics and anthropometrics are determinant domains in which to classify and characterize young swimmers' profiles.
authors.affiliation: Nanyang Technological University, Singapore, and with the Research Center in Sports Sciences, Health and Human Development (CIDESD), Vila Real, Portugal.
authors.forename: Tiago M
authors.initials: TM
authors.lastname: Barbosa
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Morais
authors.forename: Mário J
authors.initials: MJ
authors.lastname: Costa
authors.forename: José
authors.initials: J
authors.lastname: Goncalves
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Marinho
authors.forename: António J
authors.initials: AJ
authors.lastname: Silva
mesh_terms: D000054:Acceleration; D000886:Anthropometry; D054874:Athletic Performance / Q000145:classification* / Q000502:physiology*; D001696:Biomechanical Phenomena; D002648:Child; D003163:Competitive Behavior / Q000502:physiology; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D010809:Physical Fitness; D013550:Swimming / Q000502:physiology*