# Relationship between Physical Factors and Change of Direction Speed in Team Sports
## 3 Results and Discussion
### Relationship between CODS and Jump Ability  
The squat jump (SJ), or vertical jump (VJ), provides an assessment of the capability to rapidly develop force solely during a purely concentric movement [26]. Relatively unclear results were observed in the relationship between the CODS test and SJ height. Most of studies confirmed this relationship, especially in female soccer and netball players (\(r=-0.50\) * to \(-0.71\) **) [15; 17; 20] or in a mixed group of male and female handball players (\(r=0.38\) * and \(r=0.65\) *, respectively) [22]. However, this was in disagreement with another study on female basketball and soccer players [24; 27]. [PERSON] [23] also observed a significant relationship in male football players (\(r=-0.28\) ** and \(r=-0.38\) **, respectively), but the sample size of this study was very large, which could have distorted the results in terms of overpowering. Although a more relevant study showed the same results in teenage male soccer players (\(r=-0.71\) **) [21], contradictory results were observed in elite male soccer players [28]. The authors admitted that the neuromechanical variables assessed in their study were not able to significantly explain performance in the Zig-Zag COD test, in which athletes had to efficiently (and successively) accelerate and decelerate over very short distances multiple times (e.g., \(4\times 5\) m), and change direction as quickly as possible. These particular features possibly relied on more specialized motor skills, thus compromising the relationship with the standardized physical measurements used here. Based on these results, the relationship between CODS performance and squat jump height (SJH) was confirmed in most of the studies in females or in less-skilled teenage male players. However, more studies with male players are needed to reach a clearer conclusion for them. The other parameter of the squat jump is peak power (absolute and relative), which significantly correlated with the pro-agility shuttle in female basketball players (\(r=0.56\) * and \(r=-0.67\) *, respectively) [27] and with the 505 Agility test in female soccer players (\(r=-0.64\) ** and \(r=-0.65\) **, respectively) [20]. In another study, the pro-agility shuttle correlated with peak power in male and female soccer players only in relative values (\(r=-0.48\) * and \(r=0.53\) *, respectively) [15]. [PERSON] et al. [24] did not find a relationship between the time in a CODS test with \(180\)\({}^{\circ}\) turns and absolute peak power in a squat jump in either absolute or relative values in female soccer players. However, their performance in a vertical jump was significantly lower, and the standard deviation was twice as high than the performance of soccer players in previous studies [15; 20]. Accordingly, the significant difference was in the CODS test. While the test of [PERSON] et al. [24] included five \(180\)\({}^{\circ}\) directional changes, the other studies contained only one or two \(180\)\({}^{\circ}\) directional changes. Surprising findings were observed in studies using a \(t\)-test. There was a significant relationship between the CODS test and peak power in squat jump only in less skilled female players, and even that was only in relative values (\(r=-0.72\) * and \(r=-0.52\) *, respectively) [15; 20]. Considering these findings, it is more useful to express the peak power in SJ in relative values, rather than in absolute ones. Then the association with the time in CODS is stronger in both genders. In addition, we assumed that this relationship is dependent on the type of CODS and the performance level of the players. It appears that CODS tests that include lateral running or many directional changes are less determined by the power in a squat jump. Mean propulsive power in a squat jump (with additional weight on the bar) significantly correlated with the velocity in the Zig-Zag COD test and the \(t\)-test in a mixed group of male and female handball players (\(r=0.42\) * and \(r=0.51\) *, respectively) [22].