Under the right conditions I would use one, but if it's for a training issue I try to address the training issue.
With my horse, I only use one when riding in a group because he puts his head practically in my face and turns his head sideways to evade my aids. He doesn't do it as badly with the running martingale. I don't ride with others often so training is slow going. I do, however ride with two sets of reins and only use the martingale if he starts the evasion and use the reins connected straight to the bit otherwise. I try to give him a chance to do the right thing. Posted via Mobile Device
I use one that is set as loosely as possible to be effective on my gelding to keep from getting cracked in the face with his head when something spooks him. It's a bad habit for him to fling his head straight back when he gets scared. I don't need a broken nose. Haha. That's all I use it for.
They should never be adjusted tightly enough to be a training aid but used correctly they wont interfere with a horses natural head position at all - pretty much a safety net 'just in case'
I wouldn't show jump, cross country or hunt without one - those are the places when things can suddenly go wrong and you feel glad you had it. In the UK they have always been considered 'part of the traditional hunting uniform' as part of a breast plate set up usually
I used one on Looby when she was going through her head flipping smack me in the face phase, a couple of nosebleeds and a crown knocked out made me think it was a good idea to stick it on her and it worked really well
I'm also finding that when the flies are bothering them badly on the trails that if their heads are coming too close to mine I'd rather put them in a martingale and have done with it.
I have to agree with jaydee - though depending on the horse, I will jump or go xc or hunt w/o one. However my aggressive hot jumper, while usually soft and forward, will when excited toss his head up. Having been caught in the face before, the running is there to keep that from happening again. It is loose enough, however, that it won't do a **** thing for headset or anything other than keeping me from getting smacked in the face. As much as I like a running on him and his sister and don't really use them on any of my other horses, I hate standings because I feel they are just a tie down and used to cover up a training issue. Just my personal opinion (and I do know people who have used them correctly). Then again, I use a tie down on my trail horse bc he learned how to flip his head just right and get his entire bridle off on trail! Yes... really... kooky arab haha. So the tie down in his case keeps him from flipping his head up and to the side in this weird motion he does that manages to remove said bridle lol
A running martingale is intended to stop the horse's head hitting the rider in the face should the horse throw its head around like a fool. If the martingale is tight enough to be able to be used as a training aid, then it is incorrectly adjusted. The rings should be able to easily touch the horse's throat latch. If you are using a piece of equipment incorrectly, as a training aid, then there are huge holes in either your basic training or your horse's, and you should go back to basics until you can master them.