Backstroke start kinematic and kinetic changes due to different feet positioning

Karla de Jesus, Kelly de Jesus, Pedro Figueiredo, Pedro Gonçalves, Suzana Matheus Pereira, João Paulo Vilas-Boas, Ricardo Jorge Fernandes

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

The backstroke swimming start international rules changed in 2005. This study compared two backstroke start variants, both with feet parallel to each other but in complete immersion and emersion. Six elite swimmers performed two sets of 4 maximal 15 m bouts, each set using one of the variants. The starts were videotaped in the sagittal plane with two cameras, providing bi-dimensional dual-media kinematic evaluation, and an underwater force plate and a handgrip instrumented with a load cell collected kinetic data. Backstroke start with feet immerged displayed greater centre-of-mass horizontal starting position, centre-of-mass horizontal velocity at hands-off and take-off angle. Backstroke start with feet emerged showed greater wall contact time, centre-of-mass horizontal and downward vertical velocity at take-off, lower limbs horizontal impulse, and centre-of-mass downward vertical velocity during flight phase. Backstroke start with feet immerged and emerged displayed similar centre-of-mass horizontal water reach, back arc angle and 5 m starting time. Irrespective of the swimmer's feet positioning, coaches should emphasise each variant's mechanical advantages during the wall contact phases. Furthermore, the maintenance of those advantages throughout the flight should be stressed for better backstroke start performance.

Original languageEnglish
Pages (from-to)1665-1675
Number of pages11
JournalJournal of Sports Sciences
Volume31
Issue number15
DOIs
Publication statusPublished - Nov 2013
Externally publishedYes

Keywords

  • biomechanics
  • dorsal start
  • elite performance
  • swimming

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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