After linebacker James Harrison momentarily retired following the 2013 season, his future seemed up in the air again until he recently announced he would play at least one more season for the Pittsburgh Steelers at age 38.

Playing in the NFL in your late 30s is rare, especially for a linebacker, a position where a player must maintain both speed and strength. So it would seem that somebody like Harrison might need something more than just your run-of-the-mill time in the weight room, and sure enough, his workouts look insane.

Harrison occasionally posts short videos of his workouts to his Instagram account and it is clear that even at age 38, there are not many people in the NFL who are outworking the 13-year veteran.

There are dips with what looks to be about 200 pounds of added weight.

🔫🎥💪🏿🏋🏾💯💯💯 A video posted by James Harrison (@jhharrison92) on Apr 16, 2016 at 7:28am PDT Apr 16, 2016 at 7:28am PDT

There are 1,100-pound leg presses.

Leg work!💯💯💯 little over 1100lbs A video posted by James Harrison (@jhharrison92) on Jan 11, 2016 at 6:39am PST Jan 11, 2016 at 6:39am PST

They don't make dumbbells big enough for Harrison's one-armed shoulder presses.

Pull-ups with added weight because his 250 pounds of body weight are not challenging enough.

I'm not even sure what is going on here.

@theramonfoster @maurkicepouncey 240kg/528lbs it's starting to come back👀🏋🏾 A video posted by James Harrison (@jhharrison92) on Mar 31, 2016 at 6:45am PDT Mar 31, 2016 at 6:45am PDT

Harrison might be able to compete in Strongman competitions when he retires.

@theramonfoster @maurkicepouncey farmer walking 470 A video posted by James Harrison (@jhharrison92) on Mar 31, 2016 at 7:03am PDT Mar 31, 2016 at 7:03am PDT

One-legged squats are not for the weak.

2nd legs of the week A video posted by James Harrison (@jhharrison92) on Apr 21, 2016 at 6:39am PDT Apr 21, 2016 at 6:39am PDT

Apparently straight bars are not challenging enough.

Werk A video posted by James Harrison (@jhharrison92) on Apr 26, 2016 at 7:51am PDT Apr 26, 2016 at 7:51am PDT

And don't forget about the 700-pound squats.