## 4 Discussion  
The present study aimed to examine the differences in match movement profiles according to the opposition's team ranking (i.e., match balance) in the professional Spanish soccer leagues over four consecutive seasons (from 2015/2016 to 2018/2019). The novel findings of the current study were that teams covered significantly greater TD when played against the lowest quality teams (MB5) in L1, while in L2 teams covered a significantly greater TD when played against the highest quality teams (MB1). Concerning match movement profiles with and without ball possession, teams covered a greater TDWP and TDWP > 21 km\(\cdot\)h\({}^{-1}\) when playing against the highest quality teams (MB1) in both L1 and L2. On the contrary, playing against the lowest quality teams (MB5) in L1 versus the highest quality teams (MB1) in L2 implied more TDWOP and TDWOP > 21 km\(\cdot\)h\({}^{-1}\). Firstly, concerning the TD covered by soccer teams, we hypothesized that the TD would be greater when the quality of the opponent was better (Hypothesis 1). The most striking result from the data is that the TD was significantly greater when teams played against the lowest quality teams (MB5) in L1. Similar results have been found by [PERSON] et al. [26], where competing versus a \"weak\" opponent was related with more TD and TD > 21 km\(\cdot\)h\({}^{-1}\) covered during home games compared with away games. A possible explanation for this might be that top-ranked teams could be winning these unbalanced matches against the lowest quality teams, and during the matches they would use greater defensive activities because they preferred to decrease ball possession [3]. Another possible cause of this may be due to the need of these teams to win the matches to rise in the final ranking or to accomplish the goals at the end-season. Therefore, they try to reach their maximum physical performance to win soccer matches [4]. Even the higher TD covered by top-ranked teams could be explained because their players had better physical fitness levels, allowing them to reach greater physical performance. Meanwhile, teams from L2 covered a significantly greater TD when playing against the highest quality teams (MB1). Similar results were also obtained for TD > 21 km\(\cdot\)h\({}^{-1}\) during MB1. Therefore, Hypothesis 1 was only confirmed in L2 matches. These results may be explained by the fact that bottom-ranking teams have generally covered more TD during the season, as previous studies have reported [29,34,35], or may even be due to weak soccer teams needing to put in more effort during the season to win their matches [21]. Another reason could be that these soccer teams lost their matches several times and they needed to reach their maximum physical capacity to draw or win the match [4]. Concerning the TD with and without ball possession, we hypothesized that a quality opponent would significantly influence match movement profiles (Hypothesis 2). The results reported that the TDWP and TDWP > 21 km\(\cdot\)h\({}^{-1}\) were significantly greater when teams played against the highest quality teams (MB1), both in L1 and L2. A possible explanation for this might be that playing against top-ranked teams could imply adverse results and, consequently, losing teams usually increase their percentage of possession to \"control\" the game by dictating play, while weakness in the opposition defense is sought [3]. In this line, [PERSON] et al. [42] reported that the TDWP increased for each minute that teams were losing in the First Spanish Division. Meanwhile, the TDWOP and TDWOP > 21 km\(\cdot\)h\({}^{-1}\) were significantly higher when teams played against the lowest quality teams (MB5) in L1. On the other hand, playing against bottom-ranked teams could imply positive results, and when teams were ahead or drawing they chose to play counter-attacking or direct play, often using long passes, so ball possession decreased [3]. It can be suggested that the TDWOP was increased when teams were winning [18].