My QH is 13 yrs and whenever it is close to winter usually the beginning of November, he must have this habit of not wanting to work in the close and during the winter time. So lets say I bring him out in the riding ring I will warm him up by getting him the run and stretch his muscles and then tack him up and walk him for a bit, trot, and lope. And then that's the usual for in the summer but he wants it differently at this time. He try's, well I wouldn't say try but he bucks or when I ask for a trot he'll want a fast canter and when I try to slow him down he then brakes into a buck. What should I do?