Updated: Jul 2, 2021
This is a question that I am asked with great frequency. It is a practical bit of information to have the answer to, but if you delve deeper it can also become a metaphor for how we communicate with our horses both in and out of the saddle.
Wouldn't it be Nice...
How fabulous would it be to know EXACTLY how much pressure to apply, how hard to pull on the lead, what is an appropriate amount of force when asking your horse to move over. Then you could repeat the same thing over and over with the confidence of knowing, yeah, i'm doing this right!!
Even better, what would it be like to know the precise cause and effect of the amount of pressure you apply. "Every time I apply 1.5 oz of pressure in this location, my horse performs "this" behavior without fail."
No Such Luck
Sorry. There is no neat and tidy answer to question of how much you should pull on the reins or any other related activity. Why? Because it depends on the horse, situation, environment, and your relationship with said equine.
Horses are living thinking creatures. They are in different positions, frames of mind, relationships with their environments, different levels of understanding, and their abilities vary from one moment to the next. That means the way we communicate with them can be neither fluid nor fixed.
But...I Don't Want to be Too Harsh
Good!! I applaud that!! You're thinking like a compassionate horse person. The way we avoid being too harsh is by breaking down requests into easy to understand approximations of what you want your horse to do. So, if your horse to yield to rein pressure, begin by making a small amount of contact. Then wait and wait until our horse happens to move in the direction that releases that pressure. And...VOILA' We have the begun the process of teaching our horse how to respond to pressure without being harsh. Over time we build on that by asking for a little more movement of the head, then teaching it with a step at the walk, several steps at the walk, at the trot, etc. Get the idea?
Your horse will let you know if your applying pressure in a way that causes distress. Watch carefully and you will signs of tension in your horse's expression or posture if confusion or discomfort are present. If you feel your horse brace, that's another clear signal meaning defense mechanisms have engaged.
Another uh-oh moment to look for if you find yourself escalating the amount of pressure to get a response. There's a huge difference to your horse between a cue and a demand. If it feels like you have to demand to get results, it's time to rethink your approach and your horse's understanding of the cue. There may also be other factors at play such as physical restrictions, pain, or emotional upset or distractions.
It's a Trick Question!!
The answer to the question, "How hard do I pull on the reins," is...as little as possible!
The reins, lead rope or any pressure you apply should be perceived by your horse as informative - a gentle non-threatening request.
If you need to "get stronger" to get your point across, there's already a breakdown in communication.
One of the major mistakes riders make is expecting too much. Give your horse a chance to respond and if there's a glitch during the process, return to an easier version of the request that your horse can successfully perform.