Warming your horse’s muscles, and for that matter your own, is really important if you want to avoid injuries to your horse. You should continue your warm-up patterns for about ten minutes or until you feel that you have made progress with your transitions and your horse is relaxed and rhythmic, before you move onto other training exercises.
Exercise 6: Halt Across the Centre Line
This exercise can be varied to a walk and halt, depending on your level of training.
Gait: Walk or Trot
Difficulty: 
Aims: Halts, straightness and improving accuracy of turns.
Instructions
Working trot large (means trot around the sides of the arena), halt at C, working trot large, at S turn across the arena and halt across the centre line (facing R), trot on to R, right rein, turn across the arena at B, halt across the centre line (facing E), trot on to E, left rein, at V turn across the arena and halt across the centre line (facing P), trot to P, right rein, working trot large, halt at A, trot large to V. You can continue this exercise by turning across the arena at V, B and S.
Animation
Click on the image below to view an animated guide to this exercise.
Aids Used in this Exercise
All your aids will be given in the following order:
UPWARD TRANSITIONS (Walk to Trot):
Prepare > Rein > Weight > Leg > Yield
DOWNWARD TRANSITIONS (Trot to Walk):
Prepare > Body Core > Rein > Weight > Leg > Yield
NOTE: Your rein, weight and leg aids occur at almost the same time. Do not rely on your rein aids; they should be the least important aid.
Tips
By completing two circuits of the arena you will have completed 9 x Halt and 18 x Corners/Turns. This is great practice to get your turns accurate, your Halts square and Trot from Halt happening smoothly.
