She tells me that Tilly was purchased as a reschooling project which didn't really get going. This was initially because Tilly was discovered to be expecting me, much to everyone's shock and surprise. Then Tilly was found to have dodgy ligaments; she went to hospital for an operation on her hind limbs only to find that one of the fore limbs was a bit dodgy as well. Thus, Tilly is only allowed to do light work, although she is still having to trot round in circles to improve her waistline.
She says that this video clip is a good example of the wisdom of Udo Burger who says "If the horse is moving actively and purposefully forwards, it stretches of its own accord and seeks the rein contact".
She thinks it will be fun to do another video of Tilly in six months' time, ligaments permitting, and see if her way of going has improved. I think it would be more fun to measure the circumference of Tilly's tummy and see if that has improved.