Development of a pressure sensor for swimming turns

Abstract

The turn has been identified as a key factor in swimming performance in all events over 50m in length, long course and 25m, short course, with turn time being positively correlated with swimming performance. The turn (time taken from 5m into and 10m out of the wall) has been found to contribute 21% of the overall race time for the 200m freestyle, where a 1% increase in turn performance would have resulted in the swimmer who finished third in the 200m freestyle Olympic final taking gold. Within competitive swimming the tumble turn is the preferred method to change direction when swimming freestyle. The tumble turn has been described as the movement of the body around a nearly horizontal transverse axis followed by a twisting action about the longitudinal axis as the swimmer pushes off the wall. Within the literature the turn has been split into five separate stages, approach; the turn; the push-off; the glide; and the pull-out. This paper focuses on the push-off stage of the turn, looking at the angle of the feet at push off, contact time and peak force. Current literature within this area focuses on peak force and impulse, but there is a lack of data regarding the foot positioning on the wall and its affect on performance, resulting in two conflicting stand points on turn technique. These differences in opinion are concerned with where in the turn you should rotate the body 180° about the longitudinal axis, whether it should be prior to foot contact or after, in the push off phase. this paper details the research and development of an automated system that enables in depth analysis of the contact and push off phases of a swimming turn, including contact time, foot orientation, distance between feet, and lane position, and a case study where the sensor has been used.