I've noticed after my last two lessons I've had a tight/sore lower back for a few days. I have a pretty crappy lower back anyway and doesn't take much for me to twinge it, but I think the culprit might be sitting trot. I don't do a whole lot of sitting trot but it's the only thing different in my lessons that could be causing this. Anyone else out there have problems with their lower backs and sitting trot? Is there anything I should be aware of when I'm riding that can reduce this (like sitting deeper into the saddle?)? I know I need to strengthen my lower back in general, so I'll be doing additional exercises.
If it's not the sitting trot, the other thing I'm thinking of is my lesson horse - he's an absolute chow hound. There are huge hay bales at one end of the arena and he tries like hell to get at them when we pass them during our warmup walk. He also does this to grass and random wheelbarrows outside when we're walking to/from the stables/paddock. I have to brace a lot and pull him away pretty hard to keep him moving, so that could be the culprit as well.