building muscle in the back

I was riding my almost 3yo RMH yesterday bareback. Wow what a bony back he has! Is there anything I can do to help build the muscles up there?

Right now I lunge him on a long lead rope, but mostly for training because I feel he is to young to do major lunging yet. We go for walks together in the woods (I am walking him in a lead rope), up hills and down hills, and I have ridden him for short periods about 2-3 times a week. Any ideas? Am I doing enough?

You need five or seven cavalletti, adjustable for approx. Six - nine - twelve inches off the ground. The 12 inches is for canter work only.
Set them between 48 and 52 inches apart...trotting gait.

The muscles over the back are the locomotion muscles and your horse is not using them correctly.

You may also want to make sure your horse's diet is working for it.

I've been finding there is often a digestive issue going on with horses who seem to seriously resist building muscle along the topline, but are still young and have yet to develop inverted muscling due to incorrect work (in older horses too... but especially the young ones... when a horse is young it should "naturally" carry muscle, everywhere - much like how young people will often seem better "toned" than when they are older and have years of poor posture and bad habits weighing on their bodies). I didn't put a lot of faith in the digestive theory (figured it was all about the work) until talking with an equine nutritionist and doing some minor (easy, simple, and affordable) tweaking... very interesting.

So the idea is to make him lift his legs higher?

Who would I talk to about his digestion of nutrients?

Yes, while at the same time equalizing his strides. It is not the height so much as the lengthening of the strides in conjunction with the height.

You need to use a Pessoa for building back muscles up. My horse is currently using this on the lunge and it's working wonders.

I don't think gadgets are the answer for a 3year old you want him to use himself correctly and not force him. Any modification should only be done undersupervised insturction as horses can duck back to avoid which is a disaster to correct. You also want to direct the correct muscles into owrking and carrying himself.
I woukd do lots of walking up hills to get his bum under him first and once he can move on you can get him working throughh the hind L&L is good for stretching out the back muscles

Forgive me...L&L? I will continue with the hills for sure, he needs all the muscle he can get!

Sorry long and low. In the "how to" training thread it is very well explained

The pessoa I use has different settings. Alot of people go to the hardest setting first so the neck is high and head tucked in (forcing the horse into an outline) but the beginners setting just makes the horse walk long and low therefore stretching the neck and working through the back but still gives them room to lift their head up if need be. My horse is getting alot of Physio at the moment for her back and neck and the Pessoa is really working help get rid of her bad back and spasms in the neck.