The guy has 42000 minutes played and he's only 30. His teams have always lived or died on him being on. Teams have been playing him more and more physically defensively. And he plays both ways, not like some guys who only look to score or are defensive specialists.
So if he looks tired from time to time I figure it's because he's tired from busting his ass all season carrying his team like he does.
Lebron has been in a very fortunate situation of being able to pick his team not once, but twice. Recruited his team mates to join him and forced management to make trades (Wiggins for KLove), so I don't feel bad for Lebron having to carry his team. That's just sleeping in the bed you make. Plenty of other guys have stuck it out with their crappy teams, so I don't sympathize with that at all.
As for the minutes, that's a legitimate claim, but again a result of his choosing.
42,000 minutes in 12 years ... of playing in the Eastern conference. While minutes are minutes, there are certainly differences in the type of minutes. He also has had a history of playing into the 4th quarter of games and delivering for the fans (not a knock, just an observation).
As a flipside Duncan (easy comparison for me) has played 54,900 minutes over 17 seasons and still averaged almost 36 mpg this post season while putting up numbers that are statistically in line with his previous seasons.
Couple that with the differences in the style of play. One could argue that Lebron plays a more physically demanding position, you could also argue that playing in the post against 7 footers is a little more taxing night in and night out.
I'll give you that Duncan has a reduced role ... but the guy is 39 fricking years old and still putting up 20 and 10 in the playoffs matching up against DeAndre Jordan (top defensive center in the league). You won't see a guy playing harder in the 4th quarter every game of the playoffs than him.
As an apples-to-apples comparison between Lebron and Duncan:
Over their careers, they're at the following:
Lebron: 3,564 minutes per season average over 12 seasons
Duncan: 3,176 minutes per season average over 17 seasons
That comes out to about 10% more minutes per season. We're not talking a huge difference in playing time, total of about 4 min per game.
I would not argue against Lebron James being the best player of the past 15 years (maybe more). Physical specimen, jumps out of the gym, great shooter and defender. At the same time, I find that he has as many apologists and he does detractors. Either you want the ball at the end of the game or you don't. Either you want to play every playoff game balls to the wall or you don't.
It's May and it's a long season. Everyone playing out there right now is tired.