BODY ROLL AND STROKE KINEMATICAL CHANGES DURING A RACE-PACE SWIM IN BACKSTROKE

Abstract

The purpose of this study was to verify the behaviour of body roll during a 200m event racepace effort in backstroke swimming. Six international swimmers performed 6 x 50m with 10" interval at a swim velocity corresponding to the race pace of 200m backstroke. The swimmers were videoed whole body at the 2nd and 6th repetitions, for a complete stroke cycle, with four video cameras (two underwater, two above the water) for 3D kinematical analysis (APAS). Shoulder roll (SR) and hip roll (HL) were used to describe body roll. Maximal SR (48° to 52°) and HL angles (51° to 54°) coincided with the end of the initial downsweep, the variation of body roll followed a rather symmetrical and in phase pattern. In spite of a clear decrement of swim velocity from 2nd to 6th repetition (p<0.05) there were no changes in the stroke cycle or in the body roll pattern.