Most people will say that it's attack basically because it's one of the key position in football that determines victory. The strikers are usually the centre of attraction and almost everyone is looking at you. The opponent will have study you before the match so that you will not do a damage to their team.

Most times we see about 3-4 players marking Ronaldo or Messi. Being a striker comes with a lot of mental alertness, calculativeness and quick decision making. They have to position themselves properly and convert every mistake of their opponent to goals

That's strikers right? So now let's talk about midfielders

I think midfield position requires most IQ or mental abilities in the game of football. This is largely due to the fact that the midfielders control the game, set the tempo of your team play and then create chances which are converted by strikers. They win back possession for your team and mostly take set pieces.

Good midfielders are very calculative and they use their brain to calculate the pass, their positioning and decisive plays. If a team is built around good midfielders they will surely perform well. If you see good teams you will notice they normally have very good midfielders.

Every position in football requires some form of mental attributes but I think the midfield position requires more than even the attacking position. I may be wrong though

What do you guys think?