Injury or just stiffness?

[showjump]

Hi,

I have two vizzies, one is coming up to 4 years old the other is nearly one. They play all day, and as we have 8 acres, mooch/run around to their hearts content.
However for the last week i have noticed the older one is limping. Although once they are outside playing etc, shes generally fine.
I don't think shes injured herself, but its come on all of a sudden. So not sure if shes sprained something, or its arthritis.

What age do they start showing it, and hows best to eliminate one or the other?

Thanks

 

[Aru]

I'd bring her to the vet to be on the safe side.
Although some dogs get arthritis young, its not a very common issue for a 4 year old. Is it front of back leg?
A quick check up with the vet would be the easiest way to rule out anything more than just a sprain.