It's been a pretty good year for Cristiano Ronaldo. His Portugal team didn't win the World Cup, but Ronaldo was named the winner of the Ballon d'Or as the world's best soccer player for the second straight year, topping Argentina forward Lionel Messi and German goalkeeper Manuel Neuer. And let's not forget that he graced the cover of Men's Health magazine, in the United States and around the world.

What makes him the game's greatest player and a strong candidate for the world's fittest man? Here are 5 keys:

STAMINA

Ronaldo runs more than 6 miles per game. This stamina is one reason his body fat is in the low single digits. Elite-level games are often decided in the final 20 minutes, the window when Ronaldo scored more than a quarter of his goals last season.

SPEED

In a typical game, Ronaldo sprints 33 times at a top speed of about 21 miles an hour. His explosive acceleration and high soccer IQ enable him to time diagonal runs that outsmart the offside trap. He also has great balance and body control, and can change direction quickly—so when dribbling, he's the ultimate ankle breaker.

STRENGTH

Elite soccer players can be expected to squat 440 pounds, Norwegian researchers found. Strong quads are critical for an attacker, who needs to jump to head the ball on goal. A British documentary measured Ronaldo's jump off both feet at 31 inches—NBA-worthy hops. That means he can head the ball when it's 8 1/2 feet high.

POWER

Ronaldo can kick explosively, powering the ball at a ferocious 80 miles an hour. Superior technique enables him to wrap the side of his foot around the ball when taking free kicks, making the ball spin so much that it has a variable trajectory of up to 9 feet—leaving the opposing team's goalkeeper helpless.

X FACTOR

Ronaldo is able to process the game faster than other players, says Zoe Wimshurst, Ph.D., director of Performance Vision. Elite athletes develop faster eye movement, looking at up to seven places per second versus the average person's max of five. When he's dribbling at a defender, he watches for movement clues while assessing thousands of permutations drawn from hours of play—and he does this unconsciously.