Final answer:
Flexion is the resting position that allows the most joint play.
Step-by-step explanation:
The resting position (open packed) that allows the most joint play is flexion. Flexion is the movement that decreases the angle between the bones of a joint. It occurs in the sagittal plane of motion and takes place at various joints in the body, such as the shoulder, hip, elbow, knee, wrist, and fingers.