Every gym has the grunting lifters and the newbies with bad form, but that doesn’t give you permission to make fun of them. Your comments can be harmful, and as Stephanie Holdmeyer, a Missouri State University student, explains in a powerful Facebook post, you really have no idea what someone is going through.

The super-strong nursing student was mocked for wearing a lifting belt. If you knew her back story, you’d know she wore it for support after surgery. (P.S. She can wear a lifting belt whenever she wants!) Her post will stop you in your tracks the next time you think about judging the “skinny girl” or “old man doing strange exercises” at your gym.