Hip problems or something else?

[Ridgerunner]

I have an 11.5 year old golden retriever from a very good line, lately she has been having some issues with getting almost a seizure like spasm where she seems to lose control of her legs and drops maybe six inches, she then seems to recover and then goes on with life like it never happened no whimpering or anything. I am going to take her into the vet but has anyone had this happen with their dogs before?  Here heart is still going strong here she is swimming after a duck but I know she is slowing down.  She also hasn't wanted to jump into the car like she used to so I know those back hips aren't as strong as they once were. 

[Stilly bay]

good luck at the vet, hopefully they can give her something to make things more comfortable.
it almost sounds  like a spine issue coupled with old age arthritis, the vet should be able to give you more insight.

I had a malemute great dane X that lived to be 16, at age 14 she started getting arthritis and even had some spasms like you described. the vet started her on some pain meds, she lived another two years in comfort.