After a nice walk warm-up in the relative warmth of 29 degrees (yes, I was riding in a sweatshirt, no jacket) I did about 30 walk to halt transitions to help her understand the said aid for collecting. We spend a lot of time teaching horses that the calf means “go” and spending some time teaching them that the thigh and the lower back mean “rebalance” is time well spent.
She started to understand the concept well in walk and to make the appropriate changes. She even carried it forward into trot and canter well. This was a great start.