This is an excerpt from Applied Biomechanics Lab Manual With HK Propel Online Video-Loose-Leaf Edition by John C. Garner,Charles Allen,Harish Chander & Adam C. Knight.
Postural control is considered to be a complex dynamic interaction of sensory and motor responses in accomplishing the functional tasks by maintaining postural orientation and postural equilibrium (Horak et al., 2006). Postural control can also be defined as the ability to maintain stability of the body and its segments in response to the forces that disturb the body’s equilibrium (Levangie & Norkin, 2019). Maintenance of postural equilibrium occurs when all forces acting on the body are balanced so that the body rests in an intended position (static equilibrium) or when a person is able to progress through an intended movement without losing balance (dynamic equilibrium) (Kandel, Schwartz & Jessell, 2021). The postural control mechanism is a result of the sensory systems (visual, vestibular, and somatosensory or proprioceptive) and the motor systems (neuromusculoskeletal) working together with integration from the central nervous system. Degradation of any aspect of the postural control system will result in an abated ability to maintain upright balance and an increased risk of falls and fall-related injuries.
Basic Concepts of Postural Control and Balance
To maintain optimal balance and postural stability, the relationship between the COM and BOS must be understood. An object’s or an individual’s balance and stability depend on the interaction of COM with the BOS following these basic concepts: (1) the larger the area of the BOS, the greater the balance and stability; (2) the closer the COM is to the BOS, the greater the balance and stability; and (3) an object or an individual cannot be perfectly stable, unless the COM is within the BOS.
Application of Concepts and Assessments of Balance to Different Populations
The maintenance of balance is critical under both static and dynamic conditions and is not only important for humans to participate in daily activities of living, but also critical in specific tasks such as competitive sports and occupational tasks. Additionally, falls and fall-related injuries are one of the leading causes of both fatal and nonfatal injuries in various populations such as geriatric, occupational, and certain clinical populations. Moreover, balance training in fall-risk populations can lower the incidence of falls and improve balance performance. Hence, assessments of an individual’s balance can provide an understanding of the overall status of the postural control system and can help in the diagnosis, prognosis, rehabilitation, training, and prevention of falls and fall-related injuries.