With my mares first dressage show coming up, we have really been focusing on accuracy. Accuracy of transitions as well as turns. We have this major issue with our left shoulder drifting and our right shoulder cutting corners. As well as swinging our hind quarters to right when the right shoulder is the outside lead. On the other hand The transition down has naturally been easy for Heidi because she is easily collected and maintains a connection, while our up-transitions are not as clean. The upward energy and connection is not as stable when going from walk to trot or trot to canter, Heidi typically will pop her head up. She has gotten better this spring, but she still is not a firm true connection. One of the ideas my trainer and I have been working with has been the idea of body mechanics in relation to the horse’s progression. There are many positions we evolve through with training which typically advances our progress in training both rider and horse.
Any ways my little Heidi Ho and I have been working on our turns to centerline and making them accurate, and precise. The exercises that I have been using to do this are turning to center line at A as well as doing turns from B and E to center line. When doing the turn at A the initial turn should begin preparation at P and be done between F and A. At P the half-halts begin as well as the balancing to the outside rein with the horses weight balanced. 
What I have noticed with Heidi is how she typically drifts out to the left outside shoulder once on midline and when the right shoulder is the outside she cuts corners. An exercise I used to combat these issues is to leg yield right when we drift out and leg yield Left when we cut in with the right shoulder. 
When leg yielding either direction it is 1-2 steps, if turning is a major issue then leg yielding will be from center line to wall. Typically for Heidi leg yield 1-2 steps helps to straighten her enough to not drift past the center line and when cutting corners it helps to make her seem as though there is straightness. It is also important to note that when you leg yield the 1-2 steps it is because you are not on center line directly therefore it corrects the mistake.
Another exercise: If the leg yielding exercise is not working in this fashion then I have done spiral-in and spiral-out exercises on a 20 meter circle.
Spiral-in starts off in a 20 meter circle, have the horse collected and on the outside aids. Then ask the horse to take 1-2 steps to the inside creating a smaller circle while maintaining connection and body alignment on the curve. With the one time circle then ask the horse to step 1-2 steps more toward the center. 
Focus on maintaining balance and rhythm (every horse differs this may take a half-halt a simple shift in seat) and continue to do this until a 10 meter circle is achieved. Each circle is done within one complete circle but the 1-2 steps does not need to be rushed. I found that I have to take time for quality, take note of the horses body as well as my own and to not focus so much on the horses head.
Spiral-out is done as the second part of spiral-in, now while starting on the 10 meter circle you focus on moving the horse toward the outside. Maintain rhythm, balance and not allowing drifting to occur. When you ask the horse to move out the lines need to be clearly established with the outside leg and rein. I have found it easiest to ask for the 1-2 steps then half-halt with the outside and if drifting occurs then a counter bend for a step to stop the momentum of drifting. Work my way to the outside and take a break. 
What I have found is that as irritating as the fine details can be, they are what makes the exercise effective in two ways: 1. Me realizing what I am doing, and what my body is doing to make the exercise effective or a failure. 2. The horses quality of gait, balance and rhythm while being calm, and collected.
This seems to be three great exercises for Heidi Ho and I, so thought I would share.
Happy Riding! Girls have to work on our yoga skills horse and myself 🙂
Eventing4Life 