Balance (ability)
In biomechanics, balance is an ability to maintain the center of gravity of a body within the base of support with minimal postural sway.[1] When exercising the ability to balance, one is said to be balancing.
Balancing requires concurrent processing of inputs from multiple senses, including equilibrioception (from the vestibular system), vision, and perception of pressure and proprioception (from the somatosensory system), while the motor system simultaneously controls muscle actions. The senses must detect changes of body position with respect to the base, regardless of whether the body moves or the base moves.
Age-related decline in the ability of the above systems to receive and integrate sensory information contributes to poor balance in older adults.[2] As a result, the elderly are at an increased risk of falls. In fact, one in three adults aged 65 and over will fall each year.[3]
In the case of an individual standing quietly upright, the limit of stability is defined as the amount of postural sway at which balance is lost and corrective action is required. The limit of stability may be described by an irregular conical envelope above the support base.[4]
Balance can be severely affected in individuals with neurological conditions. Patients who suffer a stroke or a spinal cord injury for example, can struggle with this ability. It has also been determined that impaired balance is strongly associated with future function and recovery in some cases, particularly in stroke patients. Additionally, balance problems have been identified as the strongest predictor of falls.[5]
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[edit] Balance training
Since balance is a key predictor of recovery and is required in so many of our activities of daily living, it is often introduced into treatment plans by physiotherapists and occupational therapists when dealing with geriatrics, patients with neurological conditions, or others whom they have determined it to be beneficial.
Balance training in stroke patients has been supported in the literature.[5][6] Methods commonly used and proven to be effective for this population include sitting or standing balance practice with various progressions including reaching, variations in base of support, use of tilt boards, gait training varying speed, and stair climbing exercises.[5] The type of training should be determined by a physiotherapist and will depend on the nature and severity of the stroke, stage of recovery, and the patient’s abilities and impairments after the stroke.
[edit] Functional balance tests
Functional tests of balance focus on maintenance of static balance, balance during weight shifting or voluntary movement (dynamic balance), balance responses to manual perturbations, and functional mobility.[7] Standardized tests of balance are available to allow physiotherapists and other health care professionals to assess an individual’s functional performance. Some functional balance tests that are available are:
- The Romberg Test: used to determine proprioceptive contributions to upright balance.[7]
- Functional Reach Test: measures the maximal distance one can reach forward beyond arm’s length while maintaining feet planted in a standing position.[7]
- The Berg Balance Scale: measures static and dynamic balance abilities using functional tasks commonly performed in everyday life.[7] One study reports that the Berg Balance Scale is the most commonly used assessment tool throughout stroke rehabilitation, and found it to be a sound measure of balance impairment in patients following a stroke.[8]
- Performance-Oriented Mobility Assessment (POMA): measures both static and dynamic balance using tasks testing balance and gait.[7]
- Timed Get Up and Go Test: measures dynamic balance and mobility.[7]
- The Balance Efficacy Scale: self-report measure that examines an individual’s confidence while performing daily tasks with or without assistance.[7]
[edit] References
- ^ Shumway-Cook A, Anson D, Haller S. "Postural sway biofeedback: its effect on reestablishing stance stability in hemiplegic patients," Arch. Phys. Med. Rehabil. 1988, vol. 69, pp. 395-400.
- ^ Schmitz, T. J. (2007). Examination of Sensory Function. In S. B. O’Sullivan & T.J. Schmitz (Eds.), Physical Rehabilitation (5th ed., pp.121-157). Philadelphia, PA: F. A. Davis Company.
- ^ Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. (8 December 2010). Costs of Falls Among Older Adults. Retrieved May 15, 2011, from http://www.cdc.gov/HomeandRecreationalSafety/Falls/fallcost.html
- ^ Hutchinson, Karen J., "Changes in the mean center of balance during balance testing in young adults", Physical Therapy, 1995, 75(8):699-706 PubMed
- ^ a b c Lubetzki-Vilnai, A., & Kartin, D. (2010). "The effect of balance training on balance performance in individuals poststroke: a systematic review". Journal of neurologic physical therapy 34: 127–137. doi:10.1097/NPT.0b013e318lef764d.
- ^ Hammer, A., Nilsagard, Y., & Wallquist, M. (2008). "Balance training in stroke patients � a systematic review of randomized, controlled trials". Advances in physiotherapy 10: 163–172. doi:10.1080/14038190701757656.
- ^ a b c d e f g O'Sullivan, Susan, & Schmitz, Thomas (2007). Physical Rehabilitation (Fifth ed.). Philadelphia: F.A. Davis Company. pp. 254–259.
- ^ Blum, Lisa; Korner-Bitensky, Nicol (May 2008). "Usefulness of the Berg Balance Scale in Stroke Rehabilitation: A Systematic Review". Physical Therapy 88 (5): 559–566.
[edit] External links
- McCredie, Scott (2007). Balance: In search of the lost sense. New York: Little, Brown. 296 pp.
