To hear the Heat players and coaches tell it, with weary sighs and wry smiles, they have been carrying the weight of the world for two years.

In Game 5 of the NBA Finals on Thursday night at AmericanAirlines Arena, they can shed that burden and exchange it for the shiny, golden championship trophy.

The Heat holds a 3-1 advantage over the Oklahoma City Thunder in the best-of-7 series, and a 3-1 edge has been irreversible throughout NBA Finals history. The Heat wants to wrap it up at home rather than return to the Thunder Dome.

It’s this simple: The Heat has three chances to win one game. The Thunder must win three in a row.

But when it comes to the Heat, nothing is simple.

The Heat believes it leads the league in pain and suffering.

Even in Game 4, when it looked like the Heat would escape Russell Westbrook’s single-handed rescue mission, LeBron James fell to the floor, his legs locked by cramps.

James, who had been in the midst of redeeming himself with indefatigable playoff performances, had to be carried to the bench, where he was rubbed and iced and hydrated to sooth the stabbing agony.

The Heat fell behind by two points with 4:21 left. Miami fans inhaled. Not again. James missing in action.

This is not 2011

But 2012 is not 2011. James limped back into the game and got just enough lift from his knotted muscles to sink a three-pointer. Victory was assured.

Though not without adversity, a word coach Erik Spoelstra has uttered approximately five times a day for the past 500 days.

James, the most vilified player in the NBA, and the Heat, the most scrutinized team, have faced adversity since the Big 3 of James, Dwyane Wade and Chris Bosh announced their alliance.

They have encountered trials and tribulations of practically Biblical proportions. They are like the Big 3 of overcoming obstacles: Job, Noah and Moses.

They have accepted that a journey through unforgiving wilderness is required to reach the Promised Land.

Adversity is a relative term, of course. The NBA is a fantasyland of wealth and privilege where 400 athletes play games and wear sneakers to work.

But sports teams need barriers in order to jump higher. So athletes and coaches embrace the concept of adversity, manipulate it, exaggerate it, use it as fuel.

And such motivation often works. Heat players are fond of saying they play best when their “backs are against the wall.” The Thunder will find out Thursday how it responds to a crisis and can draw resolve from its comeback in the last round against the San Antonio Spurs, from 0-2 to 4-2.

It is a common belief in the NBA that a title must be earned, that dues must be paid. The Puritan ethic must be followed. It’s not as easy as throwing superstars together and mowing down opponents, as the Heat found out last year in its 4-2 loss to the Dallas Mavericks, a better team.

Some perspective

Dirk Nowitzki was labeled soft until he finally won, playing with a torn hand tendon. Michael Jordan needed seven years to win the first of his six titles. Jerry West lost in seven Finals before he won his first and only title. Wilt Chamberlain chased the title until he was 30. Isiah Thomas and Shaquille O’Neal lost heartbreakers before they won. Magic Johnson won five, but he also lost four.

Perhaps it’s too soon for smooth-faced Kevin Durant, 23. Perhaps it’s time for James, 27, who has a receding hairline and furrowed forehead.