## 4 Discussion
### Difference among Playing Positions in the RPs in the AP and DP of the Game  
Previous studies which have investigated the RP without the context of the ball possession have reported that RPs vary according to playing positions due the different tactical roles during the soccer match [8; 10; 13; 39]. Similarly, the present study analysed the RP in the context of the ball possession and found significant differences among playing positions in the RP during both the AP (i.e., when the team has the ball in their possession) and DP (i.e., when the opponent has the ball in their possession) of the game.  
Specifically, the CM covered the greatest total distance in the AP (4643 m), while the FW covered the greatest total distance in the DP of game (3977 m). This may suggest that elite CM contribute significantly during the AP of the game, while elite FW have an important role in defensive duties in UCL matches. Importantly, studies which have analysed the RP without the context of ball possession have demonstrated very low high-intensity distances covered by the CM [40]. However, when we observed the RP in the context of ball possession, the CM dominated in high-intensity distance in the AP of the game over the other playing positions (517 m). These findings indicate that the CM plays at the highest game pace when their team has the ball in in their possession. This may be supported by another finding of this study: the CM achieved the lowest walking distance (679 m) of all playing positions when their team had the ball in their possession.  
When the team loses the ball in the AP of the game, the players attempt to recover the ball [41]. Basically, this is the start of the DP. The players participating in the defensive  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \(\beta\) & **Std.Err. \(\beta\)** & **B** & **Std.Err. B** & **t(233)** & \(p\) \\ \hline Intercept & & & 4.66 & 2.74 & 1.70 & 0.09 \\ Walking in AP & \(-\)0.21 & 0.09 & 0.00 & 0.00 & \(-\)2.30 & 0.02 \\ Jogging in AP & \(-\)0.06 & 0.12 & 0.00 & 0.00 & \(-\)0.53 & 0.59 \\ Running in AP & 0.23 & 0.11 & 0.00 & 0.00 & 2.08 & 0.04 \\ High speed running in AP & \(-\)0.28 & 0.07 & \(-\)0.01 & 0.00 & \(-\)3.77 & 0.00 \\ \multicolumn{1}{c}{Sprinting in AP} & 0.10 & 0.06 & 0.01 & 0.01 & 1.71 & 0.09 \\ \multicolumn{1}{c}{Walking in DP} & 0.41 & 0.08 & 0.01 & 0.00 & 4.95 & 0.00 \\ Jogging in DP & \(-\)0.06 & 0.11 & 0.00 & 0.00 & \(-\)0.55 & 0.58 \\ Running in DP & 0.25 & 0.12 & 0.01 & 0.00 & 2.21 & 0.03 \\ High speed running in DP & \(-\)0.16 & 0.10 & \(-\)0.01 & 0.00 & \(-\)1.68 & 0.09 \\ \multicolumn{1}{c}{Sprinting in DP} & 0.13 & 0.07 & 0.01 & 0.01 & 1.78 & 0.08 \\ R & 0.61 & & & & & \\ R2 & 0.37 & & & & & \\ \(p\) & 0.01 & & & & & \\ \hline \hline \end{tabular} Intercept—interception coefficient, \(\beta\)—standardized regression coefficient, B—non-standardized regression coefficient, R—coefficient of the multiple correlation, R2—coefficient of determination; AP = attacking phase of game, DP = defensive phase of game.  
\end{table}
Table 5: Multiple regression calculation for total points earned at the end of the group stage of UCL.  
d duties (i.e., recovering the ball) are the farthest players from the centre of the team [42, 43]. In general, these are the players that play in attacking positions (i.e., forwards, strikers, attacking wingers). Not surprisingly, the results from our study showed that the greatest high-intensity distances (i.e., high-speed running and sprinting) in the DP of the game were covered by the WM and FW (507 m and 483 m, respectively). These findings demonstrate that players who mainly played in attacking positions had very demanding running requirements when their team did not have the ball in their possession. Accordingly, these results suggest that elite WM and FW largely contribute to ball recovery during UCL matches. However, this must be confirmed in future studies by analysing specific technical-tactical parameters.