We have rode many, many times outside. In fact, the first time I backed Riva, was outside. But I have never cantered her in the outdoor arena. Success today :) I did 'cheat' and have my daughter ride her first at canter. My husband said I better be careful letting L ride her - she was having way too much fun and would have kept riding. L thought she was much more forward than the last time she rode her.
We started with some warm up walk and trot. L was riding Henny also and he was very looky and jumpy. So, of course, Riva decided if Henny was that way, must be tigers hiding somewhere! I basically ignored her behavour and kept changing it up and refocusing her attention. We worked on 20 meter circles and some leg yielding at trot.
I then had L get on her and Riva went right in to a left lead canter for her - it was pretty smooth and rhythmic. L was able to circle her and keep her going. She switched to right lead - little tougher. L had to open the inside rein to ask for canter, then bring her hands in together and lay them slightly to the outside of her neck to keep her going. This seemed to help Riva balance and not fall in on her shoulder.
I got back on and Riva went in to left lead canter for me when asked. I was able to keep her in canter for 2 circles of about 1/2 the outdoor arena. First time I have been able to steer her in a canter and make a turn without a wall coming at us. She had good controllable speed - felt great :) We switched to right lead - Riva again went in to it when asked. I had to try a couple of times to get her to pick up the correct lead and maintain it. L's way of helping her balance using the reins worked for me also. We were just able to get 1 circle at right lead - but it was much easier to ride than ever before.
Was really glad I tried the canter outside this evening. Riva seemed pretty proud of herself also!