THERE ARE some things we should all know not to do without being told by a doctor. One is trying to act like pro wrestlers. Another is walking around with our shoes untied. Nevertheless, both these practices are addressed in the current issue of the New England Journal of Medicine, apparently for good reason.

Professional wrestling is enjoying fad status, playing to a much larger audience than it usually does and inspiring some spectators to try it for themselves. It could be quite a sight: the children divided up into tag teams, father in star-spangled tights as Captain Shazam, Defender of the Free World, and Uncle Lester playing some villain just in from Iran or Hanoi wearing a black body stocking and death's-head mask.

It can, however, "have a potentially catastrophic outcome," according to four Veterans Administration doctors who wrote a letter to the medical journal. They cited the case of a 58-year-old man who had to undergo emergency surgery for a ruptured gallbladder after being "body slammed" onto the lawn by his son, who was practicing moves he had seen in the ring.

"The authenticity of professional wrestling as a true sport will always be debated," the doctors say. (Unfortunately, this is probably true.) "However, the laws of physics are immutable. Spectacular television wrestling throws can generate a substantial, dangerous and potentially lethal force. Amateurs should leave these throws to the pros."

Elsewhere in the journal Dr. Seth B. Goldsmith of the University of Massachusetts School of Public Health comments on another current fad: leaving one's shoelaces untied. In addition to the increased likelihood of falling down, the doctor says, there are "the problems of clenched toe, a common strategy to keep untied sneakers on the feet, and bowlegged walking, a strategy to avoid tripping over one's laces."

So, don't do body slams on your parents, but do tie your shoes. And here is some other advice that, when it appears in the medical journals, you can say you read it here first: If it rains go indoors. Don't put money in your mouth. Don't read while you're driving. And get Uncle Lester out of that body stocking before he strangles.