Block height influences the head depth of competitive racing starts

The purpose of this study was to determine whether or not starting block height has an effect on the head depth and head speed of competitive racing starts. Eleven experienced, collegiate swimmers executed competitive racing starts from three different starting heights: 0.21 m (pool deck), 0.46 m (intermediate block), and 0.76 m (standard block). One-way repeated measures ANOVA indicated that starting height had a significant effect on the maximum depth of the center of the head, head speed at maximum head depth, and distance from starting wall at maximum head depth. Racing starts from the standard block and pool deck were significantly deeper, faster, and farther at maximum head depth than starts from the intermediate block. There were no differences between depth, speed, or distance between the standard block and pool deck. We conclude that there is not a positive linear relationship between starting depth and starting height, which means that starts do not necessarily get deeper as the starting height increases. There is a prevailing belief that competitive swim start depth increases with starting block height despite limited valid data to support such a notion. In fact, this belief is so prevalent that it has been incorporated into the rules of the sport. The National Federation of State High School Associations (NFHS), the governing body of high school athletics in the United States, does not allow swimmers to execute competitive racing starts from a starting block when the water depth is less than 1.22 m (4 ft), but they do allow swimmers to complete a racing start from the pool deck when the water depth is between 1.07 and 1.22 m (3.5 and 4.0 ft). In enforcing this rule, it would appear that the NFHS is operating under the assumption that competitive racing starts from the pool deck result in shallower starts than those from a standard starting block. To our knowledge, this hypothesis has not been adequately tested. Competitive racing start depth is an important issue given the potential for serious injury if the swimmer impacts the pool bottom. Mueller and Cantu (2007) reported that all but one of the thirteen catastrophic injuries resulting in “permanent