Great question. This is something that is not discussed in an extreme amount of detail in the program, let’s see if we can help. As you know, both arms start slightly bent at setup and both straighten to when the club is first parallel with the ground on the backswing. This helps to build width and begin loading the back elbow properly. From there to the TOP of the backswing, the back elbow should bend to roughly 90 degrees. Keep in mind, the front arm should remain straight and always work to straighten more throughout the whole backswing. A good way to train the back elbow is through Hand & Arm Movement 9: Baseball Throw. As it relates to Hand & Arm Movement 8: Halfway Back Loading, when the front arm is parallel to the ground the back elbow should be slightly bent. Since it is straight when the shaft is parallel to the ground and bent to 90 degrees when the shaft is again parallel to the ground at the top of the backswing, it is safe to assume a bend of around 45 degrees is proper at this point in the backswing. Feel free to have it slightly more or slightly less depending on your preference. Lauren has a tendency to create a great amount of width in her backswing so you will see her elbow slightly less bent at this point compared to the others. I hope this helps, let us know if we can provide any further clarity. Happy training.