Riders often find connecting their horses easy when they ride in a long and low frame. However, when they start to collect (shift the center of gravity toward the hind legs), they struggle to maintain that connection.
Keep in mind that a longer, lower frame is perfect for warm-up no matter what your horse’s degree of training.
Think of the training scale. Connection (#3 on the training scale) comes before Collection (#6 on the training scale). Your horse must be connected before you can correctly collect him.
Also, if you start to collect your horse and he loses the connection over his back, you need to go back to your lower frame, re-connect him and then start to shift his center of gravity back again.
Don’t try to make this balance adjustment too fast or he will get tight and tense. You can use exercises like frequent transitions skipping a gait, lateral work with a bend like shoulder-in, and smaller circles to gradually collect your horse.
You can also use collecting half halts to bring him up. These half halts are a momentary closure of seat, legs, and hands.
Give three collecting half halts when you feel your horse’s inside hind leg on the ground. As you do it, decrease the amount of ground you cover for those 3 strides, but keep the same rhythm and tempo. (i.e. If it normally takes you three strides to ride through a corner, aim for five or six strides.)
Remember that collection takes strength. Think of it as deep knee bends.
So, establish your long and low frame, then bring your horse up slightly for just a minute or two at a time. In the new, slightly-more-uphill balance, check the suppleness in his neck and poll. If he gets tight, put him long and low again.
Then bring him up less, and check for the suppleness again. When you find a slightly more collected balance and he’s still loose, plateau off there for some days/weeks until he gets comfortable.
You’ll go through many of these gradual balance adjustments always checking for suppleness.
In other words, don’t expect a horse to go from long and low to “up” in one fell swoop!
Gradually, as he gets stronger, he’ll be willing to spend more time “up”.
Just listen to your horse. If he’s tight, rigid, grinding his teeth, or losing rhythm (#1 on the training scale), he’s telling you the work is too hard at that moment.