Analysing Lucozade's Advertisement

They have put a blue background because the colour of the drink is blue. Also when people think of the colour blue, they think about the sky, water and stability. Water represents that the drink is refreshing and that it will keep you hydrated and help maintain endurance performance. The background shows two shades of blues, there is a light blue, which connotes with health and a dark blue which connotes with power. The advertisers show that the drink does not only keep you hydrated, but its good for your health and it gives you a lot of power. The yellow in the poster represents the energy that generates in your muscles when you have a drink of lucozade. The yellow is very effective for attracting attention, that is why it is used to highlight the most important elements of the poster. The yellow on the poster is associated with freshness, to show that the drink is fresh. The dark navy blue that is used for the font, connotes with power and seriousness. 
The background of the poster goes from dark to light, then you can see that there is light on most part of Gareth Bale's face but then there is not that much light on the right side of his face. 
'In a different league'→ this might mean something about football, because Gareth Bale is a well known footballer. So it can be taking about the Premier League or the Championship League. So the advertisers may suggesting that if you drink the lucozade drink then you will be in some type of special league.