Final answer:
Phase 1 of a movement in two-phase movement theories is executed with open-loop control, which is a type of control without feedback, allowing rapid and skilled actions to be executed as pre-planned motions.
Step-by-step explanation:
In two-phase movement theories, phase 1 of a movement is executed with open-loop control. This type of movement control is characterized by rapid, skilled actions executed without feedback, meaning there is no use of sensory information to guide the motion after it is initiated. Instead, the movement is planned ahead of time, and once initiated, it runs its course without modification based on sensory input. An example of this is when a soccer player makes a quick kick; the motion is pre-planned and executed without ongoing adjustments.
The concept of closed-loop control, on the other hand, involves continuous feedback and the ability to make adjustments during the movement, which is characteristic of slower, more precise actions, where spatial and temporal accuracy are critical. The cerebrocerebellum plays a crucial role in planning movements that require coordination, such as posture and gait.