Final answer:
Postural stability is achieved through the development of a central nervous system function that maintains erect posture, widened base of support, and lowered center of gravity. These aspects are pivotal in avoiding back strain and maintaining balance, with variations observed between different sexes and age groups.
Step-by-step explanation:
Postural stability is related to the central nervous system function developed in infancy that allows us to hold our bodies erect. To increase stability when standing, having the feet spread apart creates a larger base of support and lowering the center of gravity by bending the knees can further enhance stability, akin to a football player ready to receive a ball.
Additionally, devices such as a cane or walker can significantly improve stability by widening this base. In terms of physiology, having a center of gravity that lies directly above the pivots in the hips is critical for maintaining good posture and is essential for avoiding back strain and potential damage to disks. The position of the center of gravity varies by sex and age; it is lower in females than males and is located between the shoulders in young children, which presents challenges in learning to walk confidently.