Hi Phill...
"Ten pounds does not seem that significant"
I'm guilty of thinking that.
I think what got me wondering about this was because I weighed as much as I do now a few months ago, but I didn't get these spasms then. On the other hand, I know that a lot can change if given enough time. I also think the spasms would have happened anyways too, sooner or later. I increased my amount of stretching I do so hopefully that extra exercise will help.
Take care,
James.