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.

Keywords:

• Biomechanics
• kinematics
• competitive swimming
• swimming facility rules
• dorsal start

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Brazil Coordination for the Improvement of Higher Education Personnel Foundation, Ministry of Education of Brazil [grant number 0761/12-5/2012-2015]; the Foundation for Science and Technology of Portugal [grant number EXPL/DTP-DES/2481/2013- FCOMP-01-0124-FEDER-041981] and the Séneca Foundation [grant number 19615/EE/14].