Author(s): KADLUBOWSKI, B., KEINER, M., WIRTH, K., CSAPO, R., Institution: UNIVERSITY VIENNA, Country: GERMANY, Abstract-ID: 1964

INTRODUCTION:
Soccer, characterized by dynamic movements like sprinting, jumping, and directional changes, heavily relies on explosive actions for scoring goals [1]. One crucial factor in facilitating rapid force development during these actions is the stretch-shortening cycle [2]. Despite numerous studies investigating training interventions to enhance speed and jumping ability in soccer players, there is still a gap in our under-standing regarding the effectiveness of isolated plantarflexor muscle strength training [3]. This study aimed to compare the effects of combined training interventions incorporating back squats with either calf raises or plyometric training, on the linear sprint and jump performance of youth soccer players.
METHODS:
A longitudinal six-month training study was conducted with male youth soccer players (n = 89) from two elite youth training centers in Germany. Participants were divided into two intervention groups (PLY-BS, plyometric exercises + back squat; CR-BS, back squat + calf raises), and a control group (CG), which per-formed the conventional soccer-specific training only. Outcome measures included back squat and calf raise one-repetition maxima (1-RM), linear sprint times (5m, 10m, 30m) as well as the performance in countermovement jumps (CMJ) and drop jumps (DJ) from heights of 15cm, 30cm, 45cm, and 60cm.
RESULTS:
A mixed factorial ANOVA showed that 5m LS times were affected by time (p<0.001), with 1.8% reduction post-training. Group and time × group interaction effects were non-significant. For 10mLS, the effect of time (p=0.01) was significant. A statistical time × group interaction effect (F(2,78)=8.599,p<0.001,ηp2=0.181) showed that training-induced improvements were larger in CR-BS and PLY-BS than in CG Similarly, CMJ performance improved over time (p<0.005) and differed between groups (p<0.05). The significant time × group interaction (p<0.005) demonstrated that the improvements over time were greater in CR-BS and PLY-BS than in CG.
CONCLUSION:
Our findings indicate that implementing combined training interventions, which involve combining back squats with either calf raises or plyometric exercises, can significantly enhance sprint and jump perfor-mance among youth soccer players. This underscores the pivotal role of targeted strength and condition-ing measures in soccer training programs. Notably, for improving drop-jump performance, it appears that calf raises yield superior outcomes compared to plyometric training.
References
1. Christou et al., (2006). Effects of resistance traning on the physical capacities of adolescent soccer players. J Strength Cond Res, 20(4), S. 783-791.
2. De Ste Croix et al., (2017). Leg stiffness in female soccer players: Intersession reliability and the fatiguing effects of soccer-specific exercise. J Strength Cond Res, 31, S. 3052-3058.
3. Stolen et al., (2005). Physiology of soccer: An update. Journal of sports medicine, 35, S. 501-536.