We woke up this morning to my oldest boxer (6 yrs) not being able to use her back legs. She can't get up and she has to have our support just to stand. It looks like it may just be one of her hind legs. Our youngest boxer (2 yrs) is also limping around and is having trouble standing. Our guess is that when they were playing they strained something, but it's weird that both of them are having problems. Any ideas??? We are taking them to the vet, but just wanted to get feedback from others. I appreciate the help.