Introduction:
Plyometric training has become a popular training method of youth soccer players. Researchers have sought to use different forms of training to maximize performance responses.

Aim of the Study:
This study examined effects of a vertical versus horizontal plyometric jump training program on physical performance of adolescent male soccer players.

Material and Methods:
Thirty participants, aged 14.2 ± 0.7 years, were divided into a vertical group (VG; n = 10), a horizontal group (HG; n = 10) and a control group (CG; n = 10). Before and after 12 weeks of training, as well as after 4 weeks, anthropometric characteristics, sprint/repeated sprint ability within straight speed tests, speed tests with 180° turns (RSAbest/mean/total), vertical jumping ability, and the 5-repetition maximum (5-RM) load in leg curls and split squats (single right/left leg) were measured.

Results:
The VG and the HG improved significantly (p < 0.05) compared to the CG in speed tests with 180° turns, RSAbest/mean/total sprints, squats/countermovement jumps, drop jumps’ contact time, leg curls, and split squats (single right/ left leg).

Conclusions:
Adding vertical or horizontal training exercises twice a week to regular soccer training improves speed, jumping ability and maximum lower limbs strength in youth soccer players.