Sports stars with the most social-media clout

Pinning down fifth place is American wrestler Nikki Bella. Her sport may not take her to the Olympics, but this muscle-woman is one of the most popular athletes online. The reach and numbers of followers are critical marketing factors - for fashion advertizing, for instance - even if Bella isn't sporting too many clothes.

Just missing out on a podium finish this time is current Formula-one world champion Lewis Hamilton. The British race ace has a reputation for the glamor and glitz, and maintains a bouyant social media presence off the track.

In third is David Beckham. A megastar in his playing days, he hung up his boots in 2013 - but he's now an in-demand model for big-brand clothing lines. And he's still always game for a selfie!

Slamming second ... is Dwayne Johnson, known as "The Rock". Now a blockbuster movie star, he started out as a wrestler. And he still looks quite the part!

Our table-topper this week is LeBron James, the only athlete in our chart who's competed in the Olympics. He's regarded as the most recognizable brand in sports - maybe even in the entire universe.