Postural control: changes with ageing and exercise
Contribution to Book
Bezerra, P, Crowley, Z & Zhou, S 2012, 'Postural control: changes with ageing and exercise', in AM Wright, SP Rothenberg, Posture: types, assessment, and control, Nova Science Publishers Inc, New York, US.
Ageing is frequently accompanied by a decrease of neuromuscular capacities which are associated with increased risk of falls and morbidity. Postural control is one of the functional capacities that are fundamental to an independent lifestyle. Postural control is the ability to maintain the body’s centre-of-gravity within the base of support during upright stance. The sensory inputs from visual, vestibular, and proprioceptive modalities are processed by a number of structures in the central nervous system, including the cerebellum, basal ganglia, and cortex, and integrated to produce appropriate motor responses that maintain upright stance and reduce postural sway. Both strength and power, as appropriate motor responses, are important factors in the control of balance and preventions of falls. Decreased muscle strength and power associated with ageing can cause adaptations in the strategies used by the nervous system in control of posture. For example, it has been reported that there is a change from an “ankle strategy” which relies on large moments at the ankle, to a “hip strategy” which relies on moments at the hip to rotate ankle and hip joints in opposite directions. The ability in control of posture can be assessed using either traditional posturography or stabilogram diffusion analysis. Traditional postural control variables are most often characterised with the measures based on the displacement of the centre-of-pressure (COP), while the stabilogram diffusion analysis generates a stabilogram diffusion function that summarizes the mean square COP displacement as a function of the time interval between COP comparisons. However, further research is needed to identify the most appropriate postural measures for upright quiet stance. Evidence in the current literature indicates that appropriate exercise has a beneficial effect on the postural control. Amongst the training modalities that have been examined it appears that exercises that involve coordinative balance tasks, such as balance training and Tai Chi, are the most effective in delaying the age-related decline in postural control.
This chapter provides a review of current literature and our understanding on control of upright stance posture, with a focus on the effects of ageing on the factors that are essential for control of posture and the effects of exercise interventions for improving postural control