Good morning. A healthcare mystery may just have been cracked, and the suspect: Mr. Harold, in the kitchen, with a pickleball racket.

You see, a few weeks ago UnitedHealth Group said more people were using the healthcare system (bad news for insurers), and no one exactly knew what was up. Then yesterday, the sleuths at UBS published a note with a clever hypothesis: Rising healthcare utilization rates could be fueled by…pickleball injuries.

UBS calculated that the game’s surging popularity—among seniors, in particular—will contribute $377 million in medical costs this year for procedures like hip replacements and knee surgeries, Bloomberg reported.

It makes intuitive sense, but this still reeks of Big Tennis.