James Harrison is the definition of a gym rat. But to refer to him as a small rodent isn't right. Rats are not known for their laser-like focus or their devotion to training. He’s more like a gym— on second thought, no description does the work that the 39-year old puts in proper justice.

You just have to see his latest insane workout.

Now, to the novice, that may look like he is just squatting with 325 lbs. (assuming that is a standard 45 lb. bar). But the workout is actually so much more than that. With the weights attached to the bar by bands, he is forced to go slow and maintain perfect form. Otherwise, the weights start to bounce—and that’s not good.

By having the weights attached to the bar by the bands, he is actually doing an even more intense workout than the weight alone would indicate.

Have you ever wondered how he can play the position he does at his age? It is because he trains with more intensity than probably any other player in the NFL. His coaches probably wish the rest of the team trained half as hard as he does (check out his Instagram page for more videos).

But then how come the Steelers let him go? Well—because they are foolish. They wanted to get younger when they should have been taking advantage of the personnel they had. Harrison certainly proved he could still play when he signed with the Patriots.

For now, he is not committed to anyone. But despite his age, there will be someone willing to make him an offer next season.