Kay Glynn of Hastings, Iowa, is 65 and still splits my sides with her annual Christmas photo greeting. But I’m onto her secret. It’s the long hair! She apparently took the story of Samson to heart. But I doubt anyone’s angling to mow her mane. So expect her to show her superhuman strength and flexibility for years to come (especially in the pole vault). Here she is at Sky Zone trampoline park in Omaha, where she asked staff about when it was least busy. “They told me that if I were to get there right when they opened on a…