Hade chiro and accupuncture done on my gelding this morning. All went pretty well. Vet would like to see a bigger, more muscled butt. I do tons or backing (correctly), and lots of trot ground poles. 

My horse is weak in his right sacrilicius. Nothing major, just seems to always be a slight issue in chiro every time. 

Vet recommended looking into the Pessoa Lunging System. Has anyone used it? I can't do hills this time of year. Any other tips on building the hind end?

I use a surcingle with the elastic side reins and an o ring snaffle when I cant ride him... my surcingle has different rings for different head set levels. One thing I really noticed with it when lunging him is how it keeps him engaged and working from his hind end, he has to, to get the "release " from the reins .. it took a few times for him to understand but I just kept driving him forward and he figured it out. I love it. I dont use it every time just when I feel like hes getting too hollow..  huge difference in his topline and muscle development in his haunches. I can definitely tell a difference when I ride him. He travels more balanced and driving from behind instead of hollowed out, nose in the air. I've had this surcingle for over 10 years 

Lots of transitions. Cavalettis if you can, or find a way to heighten your ground poles. I kind of "jerry rigged" my own version of the system, not quite as intricate. I just got a surcingle with some side reins and then got some rope for the behind the back legs part. I used a polo for awhile to see if I liked it enough to go buy rope. I have a clip on one end of the rope & jsut tie the other end so its's a little adjustable. Not the prettiest but it was all cheap & effective 

I like a EquiAmi better. Way easier to adjust then a pessoa.  I used it to rehab my mare that fractured her pelvis and then was having SI pain. I worked her over ground poles and on up and down transitions.  I feel without that equipment and regimen she would not be back competing today. 

yes love it. After the vet recommended it daily for 3 mo for a back rehab I decided to start weekly sessions with all my horses to strengthen their backs.