sitting, well on mine at least otherwise it would be like UP............................................................................................................................................................................................................................................................................................................................................................................................ and DOWN, just would feel all wrong!
I'm teaching mine to do it just now, and he is doing very well. I started out with sitting, but he just kept trying to run rather than extend, and as he is a very panicky, flighty horse who hollows at the slightest upset it was doing more harm than good so I switched to rising. This really relaxed him as he is very focused on my seat and weight aids, so he must have felt he was better able to understand what was being asked of him as i was extending my rising.
Once he started getting the hang of the extending I prolonged my sitting periods. We are now getting around 5-7 strides of extended while sitting.
Agree with heebiejeebies one of mine was having a bit of trouble getting the hang of it, then for some reason (no idea why??) i stopped sitting and off he went. It was like a light bulb switching on for him.
I used to do extended trotting everywhere on my little Arab many moons ago. If I didn't he would jog and bolt the second his hooves touched grass. Loved it - an amazing pace. Always rising - if I sat he used to run then just bolt anyway the blighter... Miss that pony something rotten still, and its 20 years ago now...