The concept of seasons beginning and ending must seem quaint to Cristiano Ronaldo.

For the Portuguese striker, there truly is no time to rest. Competition follows competition. National team games fill the holes left by club games. And so it goes for nearly 12 months. The seasons just bleed into each other. In the last calendar year, he has racked up 6,030 minutes in 71 appearances for his club (Real Madrid) and country, more than any other European player, excluding goalkeepers.

Ronaldo's...