Sharon Price and fiance Andy Price were trying to recreate a scene from the 80s film, in a pub garden in Weston-super-Mare in Somerset, at the weekend.
Mr Price said: "We were about 30ft apart and Sharon ran and I grabbed her hips and the next thing we knew we were flat out on the floor."
The couple, who are marrying next year, are now planning a slow dance.
The 1987 film, starring Patrick Swayze, is one of Ms Price's favourite films.
"I've always watched it and me and my daughter watch it, over and over again," she said.
"We thought it would be something different.  Everybody else slow dances, so we thought we'd jazz it up a bit."
It was on Saturday, on the "spur of the moment" that the couple decided to "get a bit of practice in" and try out the famous Hollywood dance move.
"There was no build up, no warm up and that was it," said Mr Price.
"I think I knocked myself out biting the floor as hard as I did. I wasn't too aware of what was going on after that."
Ms Price is also unsure: "I can remember running towards Andy and then the next thing just struggling for breath and my back was hurting."
With him "in and out of consciousness" and her conscious but "struggling for breath" - an ambulance and rapid response vehicle were called and the couple were taken to Southmead Hospital.
The couple, who coincidently have the same surnames, said they would rethink their first dance for the wedding.
"I don't think we'll have that one at the wedding, I think we'll go for a traditional slow one and I'll let Andy choose," said Ms Price.
A couple knocked themselves unconscious practising a lift from the Dirty Dancing film for their wedding.