Analysis of pacing strategies in 10 km open water swimming in international events

The purpose of this study was to ascertain the pacing strategies employed in 10 km open water swimming events, and to define which split time was most determinant for the final performance as a function of gender and classification in International Championships. Six international competitions over the last five years were analyzed retrospectively: Olympic Games, World Championships, and European Championships. The data corresponded to a total of 437 swimmers' competition histories (257 men, 180 women). A two-way analysis of variance (gender [2 levels: men, women], classification [3 levels: 1st to 3rd, 4th to 8th, 9th and below]) was performed for each split (0-2.5 km, 2.6-5.0 km, 5.1-7.5 km, and 7.6 to 10 km) and halves (0-5 km, 5.1-10 km). The Bonferroni post hoc test was used to compare means, and Pearson's simple correlation coefficient to determine correlations between the split and the final performance (total time). In general the medal winners and those swimmers classified from 4th to 8th place employed a negative pacing strategy (the first half of the race slower than the second), in both men and women. Women, however, in proportional terms have a faster first partial (0 to 2.5 km) than men. These results could help coaches to indicate to the swimmers that the first split of the event should be as slow as possible but guarantying to be in the heading group. Thus, they would be using the aerobic energy mainly, "reserving" energy for the second and decisive split.