## 4 Discussion
This may be explained by the fact that the generation of high amounts of force and velocity has already taken place in the 10-m run-up to the start of the timed distance. Soccer players are largely adapted to this kind of situation due to the high acceleration demands over short distances during a match, which has led them to be able to attain a high percentage of their maximum speed (V\({}_{0}\)) over relatively short distances. The second hypothesis was also confirmed. Previous research has shown a relationship between strength level and CODD, where players with higher strength levels have higher CODD [5; 25]. As a novelty, in this study, the relationship with CODD was established using force variables produced in the horizontal direction (obtained through the Hzt FV profile). This outcome contrasts with previous studies, such as that of [PERSON], [PERSON], et al. [25], using vertical component variables (e.g., 1 RM-SQ relative to body weight, HS-1 RM, PP in SJ), or [PERSON] et al. [5], using acceleration rate (ACC) calculated as the rate of change in velocity with respect to the time over the section 0 to 5 m.  
The results displayed a significant direct relationship between horizontal component variables (F\({}_{0}\)) and 505_CODD [Amateurs (r\({}_{\rm S}\) = 0.622, \(p\) < 0.05); U18 DH (r\({}_{\rm S}\) = 0.626, \(p\) < 0.01); U18 LN (r\({}_{\rm S}\) = 0.510, \(p\) < 0.01)]. Previous studies such as those of [PERSON] et al. [5] and [PERSON], [PERSON], et al. [25] showed similar results. However, the higher performance group (Professional) showed a stronger inverse association between V\({}_{0}\) and 505_CODD (r\({}_{\rm S}\) = \(-\)0.511, \(p\) < 0.05), which indicates that higher ability to apply force at high velocities (shorter time available) may lead to a lower CODD. In contrast, the remaining lower-level groups (Amateurs, U18 DH and U18 LN) will need a longer time to apply the same force as the Professional group, which translates into an increase in CODD due to a lower efficiency in force application. For this reason, the results obtained in the current study show significant differences when comparing 505_CODD between Professional and U18 LN player groups. In contrast to findings from the above-mentioned studies, players with higher acceleration capacity (F\({}_{0}\)) presented better CODD efficiency. This could be due to the major role played by the management of horizontal force production during acceleration. In sports where COD is predominant, as in soccer, higher F\({}_{0}\) levels may be essential for increased performance. As the results show, players with higher F\({}_{0}\) are those who present lower CODD (specifically 505_CODD), given that the technical ability to apply horizontal force during acceleration plays a crucial role [30; 31]. As can be appreciated, significant differences in COD performance were found. The most notable differences could be appreciated between the group of higher competition level and the lower competition level group [505 test [U18 LN (\(n\) = 24)--Professional (\(n\) = 20), U = \(-\)37.7, \(p\) = 0.000], M505 test [U18 LN (\(n\) = 24)--Professional (\(n\) = 20), U = \(-\)26.9, \(p\) = 0.000], 505_CODD [U18 LN (\(n\) = 24)--Professional (\(n\) = 20), U = \(-\)6.06, \(p\) = 0.000]], among others, corroborating the third hypothesis, which expected to find COD performance differences due to competition level and demands. In this way, F\({}_{0}\), P\({}_{\rm max}\) and V\({}_{0}\) could become good indicators for the evaluation and improvement of COD performance, as it is known that these can be improved through training [33]. Together with the use of the CODD as a COD performance assessment variable because of the greater isolation of the COD action [17; 18], these could be two very useful tools for coaches due to the large amount of information provided in combination. These findings may help coaches and researchers to understand and create more effective strategies to improve COD performance by understanding the characteristics and needs of each player.