Cristiano Ronaldo and Modric go to Euro 2024 showing age is no boundary for soccer's modern stars

Aged 39 and about to play in a record-extending sixth European Championship, Cristiano Ronaldo's longevity at soccer's highest levels almost defies belief.

Luka Modric is 38, still performing for Real Madrid and will be expected to provide the X Factor for Croatia at the Euros in Germany, which start June 14,

The best players are extending their careers for longer, despite the increased pace and intensity of the modern game.

Higher levels of fitness and stamina are being demanded of athletes, but that is being matched by ever-improving expertise in how to maximize performance.