According to Bielsa, the tactical evolution of European professional football over the past few years has been focused on improving two levels, one is running ability, and the other is offensive and defensive conversion efficiency.
A player, in a football match, spends most of the time running without the ball.
Therefore, the improvement of running ability can greatly enrich the team's tactical methods.
During Guardiola's peak year or two at Barcelona, the players' running ability was quite astonishing.
To match this, under the amazing running, Barcelona also did a very good job of pressing in the frontcourt and counterattacking on the spot, and the offensive and defensive conversion efficiency was extremely high.
Therefore, during that period of time, Barcelona was almost unstoppable and invincible.
But everyone knows that this kind of scale: