Abstract

From the perspective of swimmer safety, there have been no quantitative 3-dimensional
studies of the underwater phase of racing starts during competition. To do
so, 471 starts were filmed during a meet with a starting depth of 1.22 m and block
height of 0.76 m. Starts were stratified according to age (8 & U, 9–10, 11–12,
13–14, and 15 & O) and stroke during the first lap (freestyle, breaststroke, and
butterfly). Dependent measures were maximum head depth, head speed at maximum
head depth, and distance from the wall at maximum head depth. For all
three variables, there were significant main effects for age, F(4, 456) = 12.53, p
< .001, F(4, 456) = 27.46, p < .001, and F(4, 456) = 54.71, p < .001, respectively,
and stroke, F(2, 456) = 16.91, p < .001, F(2, 456) = 8.45, p < .001, and F(2, 456)
= 18.15, p < .001, respectively. The older swimmers performed starts that were
deeper and faster than the younger swimmers and as a result, the older swimmers
may be at a greater risk for injury when performing starts in this pool depth.