EFFECTS OF DROP JUMPS ON 1000-M PERFORMANCE TIME AND PACING IN ELITE MALE AND FEMALE ENDURANCE RUNNERS.

Purpose: to evaluate the effect of drop jumps (DJs) on performance time and pacing in a field test (i.e., 1000-m) commonly used to evaluate endurance runners; and to evaluate running and jumping performances in male and female athletes separately. Methods: 20 elite endurance runners (males: n=10; 27.8 ± 7.0 years; 62.3 ± 5.2 kg; females n=10; 25.9 ± 5.3 years; 51.7 ± 4.1 kg) competing in middle- and long-distance events participated in this study. After determination of the box height associated to the best reactive strength index (RSI), athletes randomly performed a warm-up with or without the inclusion of 5 DJs with the highest RSI prior to a 1000-m track test. Performance time and pacing (250-m splits) were determined. Countermovement jump (CMJ) heights at different time points and blood lactate [La] after running tests were also recorded. Results: a possible faster 1000-m time (162.4 vs. 165.3 s) with a very likely faster first split (38.8 vs. 40.3 s) were observed in male athletes in the DJs condition. In contrast, female athletes showed a possible slower running time (186.8 s vs. 184.8 s), and a likely greater [La] after the 1000-m test in the DJs condition. Male and female athletes presented greater CMJ performances after warm-up and running tests in both conditions. Conclusions: the inclusion of 5 DJs with the height associated to the best RSI induced a possible improvement in 1000-m performance time in elite male endurance runners. The current protocol should be avoided in female athletes.