Postural instability, falls, and fear of falling that accompany frailty with aging and disease form major impediments to physical activity. In this article we present a theoretical framework that may help researchers and practitioners in the development and delivery of intervention programs aimed at reducing falls and improving postural stability and locomotion in older individuals and in those with disability due to disease. Based on a review of the dynamical and complex systems perspectives of movement coordination and control, we show that 1) central to developing a movement-based intervention program aimed at fall reduction and prevention is the notion that variability can play a functional role and facilitate movement adaptability, 2) intervention programs aimed at fall reduction should focus more on coordination and stability boundary measures instead of traditional gait and posture outcome variables, and 3) noise-based intervention techniques using stochastic resonance may offer external aids to improve dynamic balance control.
Jones, van Emmerik (NAK Fellow #512), and Busa are with the Motor Control Laboratory, Department of Kinesiology, University of Massachusetts, Amherst. Baird is with the Physical Therapy Department, St. Ambrose University, Davenport, Iowa. The writing of this article was supported by a Research Grant from the National Multiple Sclerosis Society (RG3974A2).