I bought a gelding 4 years ago with the same problems, the more I rode him the worse he got. I learned about join-up and the importance of proper ground work. I basically started him over again almost as if he had never been ridden before. I did join-up with him in the round pen, got good follow-up and then saddled him with out a bridle and turned out from me into the round pen I couldn't believe it when he bucked like a wild bronco. After he stopped bucking and ran around the pen calm again I let him come back into me. Then I mounted him and rode him in the round pen for a few minutes. I did this three days in a row, by the third day he didn't buck any more and hasn't since, it's been three years now. This did not solve all of his problems overnight but it did start him down the right road. As far as his balking and not going forward, I used another gelding that my horse would follow and that helped him to go places that he previously would not go. Monty does a series here on the Uni called Walter won't go forward, you should find this very helpful if you feel comfortable using the giddy up rope. Your horse is showing disrespect and dominance over his rider. You will need to be patient with him and do all the ground work for respect. I really didn't believe that ground work would cause such a profound change in him but it really did. If he wants to back up (my horse did this too), make it your idea, back him up and up and up until backing up isn't fun anymore and going forward will be a pleasure. Make it uncomfortable when he does the wrong thing and comfortable when he does the right thing. The other thing I would suggest is not allowing an inexperienced rider on him while this work is going on. He will take advantage of their inexperience and it will make it harder to fix the problems. Also never feed him from the hand, this also causes disrespect and can sour a horse very quickly. I hope this helps.

Hi
The above information is great. I would add that your horse is bored and sour and is telling you that he hates to work in the arena So you need to listen to him and get him out of the arena and give him a change of pace. Can you take him out on the trail? Your horse will not die if you take him out in the winter but be careful if it is muddy or slippery Horses get nervous on slippery ground. If you can't get him out then I would suggest you start doing agility work with him. Going over bridges plastic tarps through traffic cones and around barrels. He needs to be mentally challenges as well as convinced that his job is to go forward when asked. I just reread your post and he may also be tired of inexperienced riders. I don't know how well your kids ride but they may enjoy playing around on the back of the horse, but the horse doesn't always feel the same

Cheers

Great comments, the most difficult thing for us, is to find out the reason why. Once you discovered, it will be easier. But how to discover? I agree with Dennis and Kleinnep, doing ground work and offering different challenges to see the reaction of the horse. If he gets more interested and willing, maybe he got sour of a boring and monotonous work. Try to do agility with a passive rider, you on the ground to lead him and with out (also trot). Maybe the saddle doesn't fit well or he got stiff in the winter. Or try to lounge him with and without rider and see the different reactions. Slowly you will find out the reason, than you can start to change your work with him. I know it is difficult to find out, but the only possibility we have is, to try and observe very well.

Hi Iclark,
Apart from all good advice uphere, I would suggest having his back and the saddle checked.
Some behavior like you described could me caused by a saddle pinching the shoulder or not being balanced. Should the deepest point of your saddle be behind the middle, it'll give too much pressure on the horse's loins, when no ribs help carry the rider's weight.
I agree that you should not have kids riding a horse with such a problem, until you got it solved.
Meanwhile you could longline him, to keep his muscles and spine in good shape.
Let us know how things work,
Miriam

Thanks for all the advice. There's some great ideas of different things to try. The two girls riding him are not kids... one is the coach of my kids and the other trains horses so they're both experienced riders. He's done a lot of lunging and I will get him outside once the weather clears up. (Canada with ice and snow on the ground) I'm an equine massage therapist so I've checked and re-checked his back and saddle fit and can comfortably rule that out.
I'll keep you updated.
Thanks Lindsay