When it comes to excelling at basketball, NBA players know they need to stay on top of their fitness and athleticism to make it happen. Every single NBA player who takes the court clearly has the skills to make it to the highest level, and hell, they likely were the top basketball player in their hometown, state, high school, and college. But what truly separates the regular players from the All-Star talents and championship-level players?

It’s partly natural talent, to be sure, but what really separates those players is the work they do in the gym. It’s the long hours and effort they put in when they’re not on the court—and not all players are created equal when it comes to work ethic.

The ones who craft the most muscular, athletic, and strong physiques are the players who can take things to the next level. That’s how a superstar like LeBron James has been able to remain the best player in the world while playing for over a decade. Through his training, during his career with the Cleveland Cavaliers, Miami Heat, and Los Angeles Lakers, James has brought a determination to always be at his strongest that is nearly unmatched by anyone in the NBA. As he shows on Instagram quite a bit, James is constantly in the gym, doing a range of agility, strength, and speed workouts that allow him to keep his stamina up, even at the end of games. But James isn’t the only player who has taken his physique to another level.

Kawhi Leonard has emerged as one of the top players in the NBA after leading the Toronto Raptors to its first championship in franchise history before joining the Los Angeles Clippers. With his punishing defense and incredible athleticism, Leonard’s ability to take over a game has put him in a class of his own. Along with players like Russell Westbrook, Jimmy Butler, and Blake Griffin, James and Leonard have shown what working hard off the court can do.

Here’s a look at the 12 best physiques in the NBA.

The All-Strength Guide to dynamic basketball strength and conditioning

The All-Strength Guide: Basketball

Expert advice from the director of performance for the N.Y. Knicks.

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