Depends what you want them for and how good a rider you are. As with all gadgets can be beneficial for somethings but also if used badly can be detrimental.
vile things, unless you are an expert rider using them short-term to correct a very specific evasion. in this case, their use can sometimes be beneficial.
otherwise, they can do untold damage, especially to the neck, because they are so inescapable for the horse, and increase the rider's strength a thousandfold.
i always liken them to this:
your granny says she can't touch her toes. so, you have the choice, you either show her very gently how to stretch progressively, day by day, until eventually she can touch her toes (or almost!) in comfort.
or, you rig up a rope-and-pulley mechanism from her hands to her feet, and pull hard, and say "there, now you can. look."
if the horse will not work in the outline we want, there's a reason, imho. back, teeth, muscles, saddle, bit, lack of balance, babyishness, rider... there's a reason. he's telling us as eloquently as he can that something's not right, so he can't do what we want.
have a look at http://www.classicaldressage.co.uk/html/auxiliary_reins.html
very detailed debate on them.
[ QUOTE ]
your granny says she can't touch her toes. so, you have the choice, you either show her very gently how to stretch progressively, day by day, until eventually she can touch her toes (or almost!) in comfort. or, you rig up a rope-and-pulley mechanism from her hands to her feet, and pull hard, and say "there, now you can. look."
[/ QUOTE ]OMG, I know that's not meant to be funny but I just nearly wet myself...