Investigating the effect of post activation potentiation during warm-up using vertical and horizontal drop jump on repeated sprint performance with countermovement jump in young handball players. Methods: The study sample consisted of 12 handball players (age: 15.6+0.7; height:1.780.08; bodymass;66.9+11.5). Visits from 1 to 4 were assigned for familiarization to the tests protocol, vertical jumps and repeated sprint performance with and without changing of direction, as well as to measure the performance of the repeated sprint without changing of direction (6 x25m) and the performance of repeated sprint with a changing of direction 6(12,5m x 2). During the next visits, the following three research conditions were applied randomly to players: 1) Warm up without drop jump + repeated sprint test with or without change of direction with countermovement jump. 1) Warm up with vertical drop jump + repeated sprint test with or without change of direction with countermovement jump. III) Warm up with horizontal drop jump + repeated sprint test with or without change of direction with countermovement jump. Results: The results of the study showed that performing horizontal drop jump during warm-up improves performance of repeated sprint in 25m and (12,5m x2) for indicators best time, total time, 10m A & 10m B comparison warm up without the drop jump (p<0,01), warm up with drop vertical jump (p<0,05). As the results showed the vertical drop jump performance during warm-up improves performance of the countermovement jump reference (first CMJ performance just after the warm up) repeated sprint performance, in comparison to warm up without the drop jump (p<0,01), warm up with drop vertical jump(p<0,01). Conclusion: post activation potentiation during warm-up using horizontal drop jump improves repeated sprint performance with or without changing of direction. While post activation potentiation during warm-up using vertical drop jump improves the performance of the reference countermovement jump.