A Russian powerlifting champ fractured both his knees and snapped both his quads in an 800-plus-pound squat attempt gone horrifically wrong … and the video is TERRIFYING.

The awful scene all went down when decorated weightlifter Alexander Sedykh stepped up to the bar at a World Raw Powerlifting Federation event near Moscow this past weekend.

Sedykh — the event’s champ just a year ago — loaded up 800 KG (roughly 880 pounds) on the bar … and when he went to squat it, things took an awful turn.

In the video, you can see Sedykh’s legs wobble … before they eventually give out with a loud cracking sound.

Immediately, Sedykh is in serious pain … and after he was rushed to the hospital, he reportedly required hours of surgery to fix his broken legs and quadriceps muscles.

“The main thing is that I must lie motionless in bed for two months,” Sedykh reportedly said of the injuries. “Then I’ll be taught how to walk again.”

He added, “It’ll take time to recuperate” and “I’ve had my quadriceps re-sewn and my knees put back together.”