Can anyone help me as I need some advice on how to strengthen up my dogs loins, they don't lack muscle as such but need to strengthen through, my dogs breeder hasn't go any idea either!

id be interested in this too.

Is it a problem with the topline, difficult to understand what it is you need to strengthen as although there are muscles in the area of the loin I am not sure if you have a stability or construction problem rather than something that can be strengthened. Can you explain please.

Top line is fine, maybe I'm calling it by the wrong name? The side part which I've always called the loin, just checked on some pages it's the flank..
Basically the part between the rib cage and thigh on the side of the dog!

Hope that makes sense :-)

I had a rally trial yesterday where a girl was offering free quick movement assessments, she is a chiropractor or something like that. She said my younger girl in particular needed to build up more core body strength, whether this is similar to loin / flank area I'm not sure. She recommended working her more on the right hand side to be less one sided, and walking her over very low poles, just a couple of inches off the ground. Might be worth seeing a chiropractor for your dog?

Perhaps you mean weakness generally in the coupling area and I think the only way to firm that is to exercise at the extended trot which means using a bike, your don't really want an all out gallop but you want faster movement then you are able to manage unless you are a sprinter or the dog a Chi.

Wobble boards and the like are good for this apparently - never used one but know they are becoming ever more popular in the agility world.

This website has lots of products that might be of help - although a US site I believe there are stockists in the UK
http://www.fitpawsusa.com/

Thanks for the input.. Great ideas, loved the link and maybe ill find cheaper over here

I think begging is good for strengthening that area and the stomach and back muscles.  I was always told to not have my dog standing on his hind feet for a short time, let alone a long time because it stresses the back and hips.  But lately I've seen instruction to encourage the begging position for it's strengthening but of course starting out with very short times.  Somebody on another board I go on is doing that in his agility classes, I think.  Any agility folks here know?

I saw a photo of a trainer abroad getting a dog to sit on one of those big exercise balls in the beg position, I thought it looked a bit precarious and would have been worried it may fall off. :/

I get my dog to stand on his hindlegs with his paws on my shoulders to stretch out his muscles as part of his warm-up routine before starting agility. I also stretch out each of his legs in turn when he is standing on the floor - all standard part of my dog's warm-up. I also do the same at the end of a session.