"I read recently that JFK was attempting to engage in marital activity with a woman not his wife at the White House pool a few weeks before the assassination. In the process of being rebuffed, he injured his back, causing him to wear a back brace..." That account was given in Seymour Hersh's, The Dark Side of Camelot. While not necessarily the most credible of writers, this book is one of his better documented pieces.
Gosh - hate to quote that looney. But then again, a clock's right twice a day, no?