title: Are the new starting block facilities beneficial for backstroke start performance?
abstract: We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = -0.82; 95% CI: -1.56, -0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = -0.81; 95% CI: -1.55, -0.07), centre of mass (CM) vertical positioning at first water contact (SMD = -0.97; 95% CI: -1.87, -0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: -0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.
authors.forename: Karla
authors.initials: K
authors.lastname: de Jesus
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.
authors.forename: Kelly
authors.initials: K
authors.lastname: de Jesus
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.|b Department of Physical Activity and Sport, Faculty of Sports Sciences , University of Murcia , Murcia , Spain.
authors.forename: J Arturo
authors.initials: JA
authors.lastname: Abraldes
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.|c Department of Physical Education , University of Fortaleza , Fortaleza , Brazil.
authors.forename: Alexandre Igor Araripe
authors.initials: AI
authors.lastname: Medeiros
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.|d Porto Biomechanics Laboratory , University of Porto , Porto , Portugal.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Fernandes
authors.affiliation: a Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport , University of Porto , Porto , Portugal.|d Porto Biomechanics Laboratory , University of Porto , Porto , Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Vilas-Boas
mesh_terms: D000293:Adolescent; D000328:Adult; D000842:Ankle; D000843:Ankle Joint; D054874:Athletic Performance; D001696:Biomechanical Phenomena; D005528:Foot; D006225:Hand; D018737:Hand Strength; D006801:Humans; D007717:Knee; D007719:Knee Joint; D008297:Male; D011187:Posture; D013550:Swimming; D014867:Water; D055815:Young Adult
chemical_list: D014867:Water
keywords: Biomechanics; competitive swimming; dorsal start; kinematics; swimming facility rules