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Advisor(s)
Abstract(s)
The aim was to compare the anthropometrics, biomechanics and energetics in young
swimmers of different competitive levels. Seventy-five boys aged between 11 and
13 years-old with a broad range of performances were ranked based on their personal
best time in the men’s 100m freestyle event and then split-up into three tiers (Tier-1,
i.e., top-tier, best performers; Tier-2, mid-tier; Tier-3, lower-tier). A set of anthropometric
features was measured (height, body mass, arm span and trunk transverse surface
area). Stroke kinematics (speed, stroke length, stroke frequency) was assessed by a
Speedo-meter. Swim efficiency was then estimated (stroke index, speed fluctuation,
Froude efficiency). Hydrodynamics assessment encompassed the estimation of active
drag and drag coefficient by velocity perturbation method and a set of dimensionless
numbers (Froude, hull speed, Reynolds). Mechanical power (to overcome drag, transfer
of kinetic energy to water, external power) and power input were derived. There was a
significant variation with moderate effect sizes in all anthropometric features but the
trunk transverse surface area. Tier-1 swimmers were taller, heavier and with longer
limbs than remaining counterparts. There were also significant variations in the stroke
kinematics with moderate-large effect sizes. Tier-1 swimmers showed higher stroke
frequency, stroke length, speed, stroke index and propelling efficiency but lower speed
fluctuations. Reynold number, Froude number and hull speed were significantly higher
in Tier-1 swimmers, denoting large effect sizes. The mechanical power and power input
delivered were significantly higher in tier-1 swimmers, showing moderate effect sizes. As
a conclusion, it was noted significant variations, with moderate-large effect sizes, among
the three tiers, for the vast majority of the selected variables. The better performances
by tier-1 swimmers were related to their anthropometrics, biomechanics and energetics.
Description
This work was supported by the national funding through
the Portuguese Foundation for Science and Technology,
I.P., under the project UID/DTP/04045/2019, and European
Regional Development Fund (FEDER) under the COMPETE
2020 Programme for Competitiveness and Internationalization
(POCI) (POCI-01-0145-FEDER-006969). RB is an FCT-Ph.D.
scholar (SFRH/BD/142009/2018).
Keywords
Swim stroke Efficiency Hydrodynamics Mechanical power Power input Youth sports
Citation
Barbosa, Tiago M.; Bartolomeu, Raúl Filipe; Morais, J.E.; Costa, M.J. (2019). Skillful swimming in age-groups is determined by anthropometrics, biomechanics and energetics. Frontiers in Physiology. ISSN 1664-042X. 10:73
Publisher
Frontiers Media