Some gymnasts and coaches prefer to begin the full turn from a lunge position, others from a regular step forward, and some like to start the full turn from a fourth position. Here are several passe full turns beginning in a fourth position.
Observe how the gymnast centers her body weight support evenly between the two feet with the legs in a demiplie. Consistent success in any type of beam turn depends on placing the center of mass as vertical as possible on top of the turning foot.