Sudden behavioral change

Question
I have been riding a schooling horse for about six months, and just recently, his behavior has changed dramatically. He is a 16 year old 16.2 hand quarter horse gelding cross, situated in an outside paddock(with shelter)with two other geldings, whom he gets along with very well. On the ground, he is a large puppy-dog. He has always been a "sensitive" horse, and demands deviation from traditional methods of riding from the rider. For instance, I ride him with my legs much more forward than I would on another horse. He is also pretty head shy, although I have been able to get him to trust me enough to rub his forehead sometimes. He's easy to catch in the paddock. He has always had difficulty in bending his body, and we have been working on that. I have to use the left rein and leg to go right, and vice versa. Within the last month, he has become increasingly agitated when he is ridden. When I gently move my legs against him to ask him to transition to a slow trot, he takes off. I used to be able to jump courses with him easily, and he never refused a jump. He was always very willing. However, now, even approaching a 1/2ft crossrail, he will start to rush forward, stop, back up, or spin around. He has never bucked or reared with me, or anyone else. I have to walk him up to it, and ask him to trot the last few steps. He has developed similar behavior even more recently on the flat work. He's not bad for the first half hour, but after that he's done. I have been trying to keep him interested, and switch up my routines, and doing more flat work, but he continues to exhibit clear signs of him being "done". His feed has not changed, and the vet gave him a clear bill of health. Just this last week, I have been giving him a neck massage to help ease his tension. He seems to perform better with a "neck stretcher", but some of the trainers don't like to use it. He went from jumping 3' courses with ease to not being able to approach a small crossrail at a trot. I have been trying to be very relaxed, because I know that horses can pick up on a rider's tension.  He was given a two-week break, with just light lunging 3-4 days a week, but has not changed. Perhaps it's the cold winter? I just want to make sure that I am doing everything that I can as a rider to help him. If you have any suggestions, they would be much appreciated. Thanks, Meg

P.S.: I do not believe that he is ridden in lessons more than 6 hours a week, and those who do ride him are competent riders.

Answer
Hi Megan!

I cannot give training advice to non-owners of the horse in question.

However, I can say in the broadest of terms, the life of a schoolie is not an easy one.  They can become very resentful of the many and diverse riders they must correctly perform for.... 100% of the time.  It is a mentally tiring life, more than anything, I feel.  Either they turn off their minds and just go or they quickly find defensive moves to avoid working or having to deal with riders who are "learning" what the schoolie already "knows".  It's not super fun happy time for them...it's a job.  And just like humans, sometimes they simply grow to hate their job.  Good days, bad days and all that.

My lesson horses take years to make, require constant supervision to keep mentally happy, correct for their students and are worth a million dollars to me for all the care they return to their often awkward but well-meaning riders  :-)

Good luck and remember to always wear an ASTM/SEI approved helmet!

Solange