Better trot

I am warming up, I have just asked Gally to trot, and since he is not making much of an effort I dig a spur in. Bang. Like a flash we end up on the opposite side of the arena, heading for the jumps. I've lost a stirrup, but that doesn't worry me at all. We go over two jumps, and the horse keeps rushing forwards, seemingly terrified. I bail.

I get back on and take a solid contact on the rein, and ask for a more serious effort. Everything is fine. The rest of the dressage work goes very well. In fact, I start to notice a real improvement in the trot. It's like it has body and soul, and makes me feel quitely confident about Sunday's horse trials.

So why the outburst at the start?