I personally lean towards the extra intensity. It's an open secret that all the top level players/teams are using the blood doping and other tricks to increase oxygenation levels and recovery times. The tactics of the game such as constant high level pressing keep players running further and faster than in the past. If you watch old highlights from 20 years ago, the space players have in the midfield is unreal compared to the compactness and speed at which players are closed down today.
I personally lean towards the extra intensity. It's an open secret that all the top level players/teams are using the blood doping and other tricks to increase oxygenation levels and recovery times. The tactics of the game such as constant high level pressing keep players running further and faster than in the past. If you watch old highlights from 20 years ago, the space players have in the midfield is unreal compared to the compactness and speed at which players are closed down today.