Pittsburgh Steelers veteran linebacker James Harrison is still a workout freak. Even after 13 seasons in the NFL, he still grinds every summer to prove he can play another year. But what the 38-year-old did this time will blow your mind.

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Harrison posted a video to his Instagram showing him doing a 594-pound Hip Thrust. This exercise is the secret to why Harrison can still be productive after all these years. The Hip Thrust is a glute exercise that builds strength, speed and power—all necessary for Harrison to have success on the field.

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This is why although he’s one of the oldest players in the league, Harrison still gives his team elite level production. Last season, he recorded five sacks, one interception and two forced fumbles for the Steelers.

Watch Harrison hip thrust a crazy amount of weight six times with little struggle:

[instagram src=”https://www.instagram.com/p/BIFgD8agcIZ/?taken-by=jhharrison92″]