Nikki is like that sometimes.. At first I just fought with her doing flexing, bending, backing..Nothing worked, it just frustrated us both. I've gotten to the point of knowing that Nikki will never be a pokey trail horse, she'll walk but it's a fast walk, she wants to work. At a show if she starts doing it she immediately gets taken away from the arena and we go lope circles for a few minutes. It brings her mind back to me and she gets to "work".. She's not thinking about bending and flexing, she's listening to my legs, seat, hands..We'll do a few circles each way and if she's still feeling frisky I will just keep her moving doing different things. As long as I have her moving at a show she's not getting hyper and turning into a giraffe..
Are you standing at the arena watching other people run? I can't stand by the arena on Nikki, she gets worked up and uses all of that excitement and energy just standing at the arena and wanting to run, she'll literally lunge at the gate when someone runs out thinking it's her turn. I work away from the arena and just keep walking around then when my name is called I let her trot up to the arena, crow hops into the chute and then by the end of it I'm pushing her into her stride...
I'm usually not for it but have you thought about breezing her? That way she gets that energy out in a good way, you can work on your seat and how she listens to you at a good amount of speed, then bring her back down slowly, long trot around, then do the bending and flexing..Then back down to a walk..You used up that energy in a good way, not fighting with her.. I've started doing this with Nikki about once every two weeks or so..Maybe once a week if she absolutely needs it but that's very rare.. If you're just going to trails and that jazz I would just lope circles before you went out on the trail, use that energy in a positive way, not fighting with her on the trail.. It's all about redirecting that energy in a positive way and not you both getting frustrated.
I've always ridden Nikki is a snaffle combo, it's what I bought her in.. If you want to bit up a little, I ride Lark in a hack combo bit..It's a chain mouth piece but it's actually a very light bit. It also works off of the nose arena so it's an equal pressure on her face..Not just her mouth. When a snaffle just wasn't working for her I moved her to it with great success.