Falls and their consequences are among the major problems in the medical care of older individuals. The long-term goal of this research is to a mechanistically derived therapeutic intervention to enhance muscle power, weight-shifting capability, and lateral balance to prevent falls. When human balance is challenged, protective stepping is a vital strategy for preventing a fall during activities of daily life. Many older people at risk for falls have particular difficulties with successfully stepping sideways as a protective response to loss of balance in the lateral direction. We propose that age-related declines in lateral balance function through impaired weight transfer and protective stepping linked with falls, result from neuromuscular and biomechanical limitations in hip abductor-adductor (AB-AD) muscle power generation. Moreover, we hypothesize that these functional and neuromotor impairments can be improved with high velocity muscle resistance power training. The specigic aims are:
Aim 1. To determine the age-associated changes in neuromuscular and biomechanical performance of the hip joint AB-AD musculature by evaluating the isolated maximum torque and power production and neuromuscular activation patterns.
Aim 2. To determine the aging changes in neuromotor performance of the hip AB-AD musculature during the pre-step weight transfer phase of waist-pull induced side stepping and voluntary reaction time stepping.
Aim 3. To establish a first line of evidence showing that hypothesized aging deficits in sidestepping caused by neuromotor impairments in hip AB-AD muscle power production may be reversible, we will determine the effects of velocity dependent muscle resistance power training (3 x/week x 10 weeks) compared with strength training on neuromuscular, biomechanical, and functional performance outcomes. Overall, the studies will identify age-related neuromotor mechanisms of abnormal hip AB-AD muscle power production that impair lateral weight transfer, balance stability, and mobility function. Establishing a first line of support for the superiority of velocity dependent power training over strength training on muscle performance and protective balance and functional mobility outcomes, will lead to a future comparative intervention trial to enhance these functions and prevent falls in older adults.
The relevence of this research to public health lies in its focus on understanding the causes of age- associated loss of balance function leading to falls, and on the development of effective therapeutic interventions for minimizing the devastating economic, societal, and personal consequences of falls among older people.
