# The Effect of Integrative Training Program on Youth Soccer Players' Power Indexes
## 4 Discussion
Also, the intensity of the program was low to induce adjustments that would affect speed (e.g., maximum power and rate of force development). Change of direction is a particularly crucial skill for soccer players [37]. During a match, they perform numerous accelerations, decelerations, and changes of direction [8; 38]. In the present study, a significant improvement in Illinois agility test completion time was observed for the EG group (EG: 2.6%) but not for the CG group (CG: 0.7%). Similar findings are reported in other studies. Specifically, [PERSON] et al. [21] observed improvement in the ability to change direction in the arrowhead test following their intervention. Additionally, [PERSON] et al. (2023) [39] reported improved change of direction ability with a ball in the intervention group. Also, [PERSON] et al. [23] observed a significant improvement in performance in the EG group after 12 weeks of intervention. However, there are studies where performance did not change after the application of integrative neuromuscular programs. Specifically, [PERSON] et al. [22] did not observe changes in both the arrowhead test and the Illinois agility test. Change of direction, as mentioned in previous studies, is influenced by the stretch-shortening cycle mechanism. The rapid transition from eccentric contraction to concentric contraction is a fundamental characteristic of the stretch-shortening cycle mechanism. It has been reported that integrative neuromuscular training programs can positively impact the efficiency of this mechanism [21]. Therefore, the improvement in performance in change of direction may be attributed to the positive influence of the intervention program on the stretch-shortening cycle mechanism [40]. Another factor that can influence rapid change of direction is the eccentric strength of muscles. High eccentric strength aids in quick deceleration, proving particularly significant for rapid change of direction [39; 41]. From the above, we observe that the number of studies examining the impact of integrative neuromuscular training (INT) programs on physical performance indicators in young soccer players is limited. Additionally, research findings are diverse. The lack of agreement can be attributed to various factors, such as the participants' level, different exercises, varied program volumes, and differences in program intensity, as well as other characteristics of the load, which vary between applied programs. It is important to note that the higher the participants' level, the more challenging it is to observe significant changes in the studied physical performance indicators. Another crucial factor that can influence results is the age of the participants. For this reason, their biological maturity was estimated using the equation of [PERSON] et al. [25], and children in early or delayed biological maturity were excluded. This was done to attempt to limit the effects of biological maturity on the performance of young soccer players as we know that children of the same chronological age at this stage of development may differ in biological maturity, significantly affecting their performances [42]. Single-leg strength exercises must be essential components of a well-rounded fitness routine, targeting stability, balance, and muscle strength. These exercises, such as single-legsquats, jumps, and deadlifts, challenge the body to support itself on one leg, activating various muscle groups including the quadriceps, hamstrings, glutes, and stabilizing muscles. Incorporating single-leg exercises into the workout routine not only helps improve overall strength but also enhances functional performance by mimicking real movements that often require one leg to bear the load. Moreover, these exercises contribute to injury prevention by addressing muscular imbalances and promoting joint stability. In this study, most of the exercises were chosen to be unilateral (six out of eight). Unilateral exercises were used also in recent related studies [21, 23, 39]. The study has some limitations.