A deep stretching class called Contorture does more than burn calories.

“[It] builds strength in the lower abs and back, and opens [the] hip flexors,” says creator Jonathan Nosan. “Those three spots are the key to safe, strong, exciting sex.”

It’s worked for one 60-year-old money manager living in Brooklyn.

“It’s easier to get into positions,’’ he says.“From behind I can have one leg in front of [my partner] and one leg behind. It’s a lot more fun.”

But there are downsides. He says: “I’ve gotten cramps from being in unusual [sexual] positions!”