Effects of combined plyometric, strength, speed and change of direction training on youth male soccer players on physical performance: A randomised controlled trial

The objective of this study is to determine the influence of short-term plyometric or combined training (6 weeks) within regular soccer practice on the jumping and change of direction actions of young soccer players during the season. Thirty players were randomly assigned to three groups: plyometrics (PL), plyometrics + speed + Change of direction (COD) (COMB1), or PL + speed + COD + strength (COMB2). All players trained soccer 3 times per week and the experimental groups change the typical tactical warm up with a proposed PL or combined training program for 20 minutes (2 days per weeks) for 6 weeks. Before, after training, free-arm countermovement jump (CMJA) and L-RUN tests were analysed. Within-group analysis showed substantial improvements in CMJA (ES: 0.73;1.27;1.16) in COMB1, COMB2 and PL while COMB1 and COMB2 also showed substantial enhancements in COD tests (ES: 3.75; 2.15). Between-group analysis showed substantially greater improvements in COD variables (p ≤ 0.001; p ≤ 0.001) in experimental groups in comparison to PL. Finally, COMB1 and COMB2 showed no significant enhancements in L-Run (p ≤0.234). The replacement of some low-intensity football drills with PL combined with strength, sprints and COD. during warm-up may be a possible option to optimise jumping and change of direction ability during in-season football training.