Creates a bond and a sense of respect between you and horse
Establishes you as a trusting leader.
It gives the horse a choice of accepting the human as herd leader or not. The horse is not forced to but the horse learns it is easier to accept you as leader than to not. Make the correct answer the easy one as usual!
May need a lunge whip, lead rope, crop, depending on how sensitive the horse is. This is only meant to drive the horse forward, not to hurt or punish the horse.
A round pen is highly preferred.
An arena is not preferred because the horse can entirely evade pressure or get “stuck” in a corner.
It is possible to do join up without a round pen on a regular lunge line.
Patience. It can take a while for a horse to join up.
An air of confidence and calmness. You need to be the sturdy leader and it’s not going to happen if you are nervous. Remember, a horse will reflect your own emotions!
Introduce your horse to the round pen if they are unfamiliar. Spend some time just leading them on a lead rope.
Send horse out on a circle. Lunge as usual to start. Since you are in a round pen, you do not need a lunge line. It also makes changes in direction harder and presents a trip hazard.
We are looking for the inside ear to lock onto you or for the head to dip in towards you. Other good signs include licking/chewing and a drop in head carriage.
At this point, tell the horse “whoa”. Stop your body and stop sending signals. Take a deep breath and relax everything. Drop eye contact (pressure).
We are waiting for the horse to stop and look at you or even better, stop and walk up to you! Reward the horse by scratching between the eyes, scratching the neck, or scratching the withers. These are all ways horses show each other affection and reassurance.
If the horse does not join up (is not paying attention to you), send them back out on the circle. If they are running around aimlessly, work on directional switches.
Now, if the horse has truly joined up, the horse will follow behind you! They will stop when you do and walk when you do. If not, send them back out and do it again.
Walk one circle in one direction and reward. Switch directions and reward again.
https://www.wikihow.com/Join-Up-With-a-Horse
https://www.thesprucepets.com/horse-training-what-is-join-up-1886681