The biggest athlete in professional sports is also the biggest athlete on Twitter.

NBA star Shaquille O'Neal has the most followers of any athlete on the social media site, with over 3.5 million users reading his tweets. Brazilian soccer star Kaka is second on the list, more than 500,000 followers behind.

Though athletic success is a good yardstick in determining which men and women have the most followers, it's not as reliable an indicator as you'd think. For instance, Tiger Woods isn't in the top 10 but Chad Ochocinco is. (Tiger actually has fewer followers than fellow golfers Stewart Cink and Ian Poulter.) LeBron James cracks the list but comes in behind Reggie Bush. And of all the baseball players with accounts, one-time All-Star Nick Swisher is the most popular. (It doesn't hurt that he's on the New York Yankees.)

Here's the list of the top-10 athletes on Twitter, along with a sample tweet and a summary of their favorite subjects:

1. Shaquille O'Neal -- @THE_REAL_SHAQ -- 3,564,335 followers -- 51 tweets (in the month of February)
2. Kaka -- @kaka -- 2,934,112 followers -- 57 tweets
3. Serena Williams -- @serenawilliams -- 1,931,286 followers -- 412 tweets
4. Cristiano Ronaldo -- @Cristiano -- 1,914,172 followers -- 88 tweets
5. Dwight Howard -- @DwightHoward -- 1,874,255 followers -- 22 tweets
6. Paul Pierce -- @paulpierce34 -- 1,745,039 followers -- 69 tweets
7. Chad Ochocinco -- @ochocinco -- 1,741,178 followers -- 630 tweets
8. Reggie Bush -- @reggie_bush -- 1,555,080 followers -- 61 tweets
9. LeBron James -- @kingjames -- 1,492,952 followers -- 46 tweets
10. Nick Swisher -- @nickswisher -- 1,273,939 followers -- 64 tweets
Read More: sports.yahoo