Effect of Different Strength Training Modalities on Maximal Strength and Power in Semi-Professional Football Players

The study provides an innovative perspective on comparing two training modalities of strength training to evaluate the effectiveness in enhancing maximal strength and power of lower limb strength. Our study aimed to examine the effects of eccentric and concentric strength training on the development of maximal lower-limb strength and power in semi-professional football players. The study involved 28 players (age 21.7 ± 2.1 years, body height 180.1 ± 4.6 cm, body weight 75.9 ± 7.2 kg) divided into eccentric (ECC), concentric (CON), and control (CONTR) groups. The eight-week training intervention targeted the knee extensors and flexors. Knee flexor strength was developed using the lying leg curl machine, and knee extensor strength using the seated leg extension machine. The concentric group trained with the maximal effort method, while the eccentric group applied the 2/1 eccentric method. The results showed significant improvements in maximal strength of the extensors (CON +19.4%, p < 0.001, d = 1; ECC +19.42%, p < 0.001, d = 0.89) and improvements, but not significant (p = 0.11, ηp2 = 0.16), of the flexors (CON +12.81%, ECC +12.14%) of the knee joint. No significant improvement in power (p = 0.11, ηp2 = 0.16) was observed, measured by standing broad jump performance. These findings highlight the specificity of training adaptations, where improvements in maximal strength may not directly translate into enhanced power. The study emphasizes the importance of both training modalities due to their sport-specific benefits for football, such as acceleration, changing direction, positive effects on muscle architecture, and injury prevention.