Community-based Power Training in Faller and Non-faller Older Adults: a Feasibility and Fall Risk Study.

Aging leads to substantial alterations in the nervous and skeletal muscle systems that ultimately lead to a reduction in "neural drive" and motor performance. While maximal strength starts declining as early as 50 years of age, aging brings even greater reductions in rate of force development and muscle power, that has been shown to be a stronger predictor of functional independence and balance impairments.

Falls are a major health concern as one third of adults over 65 years loses balance and falls every year, and based on a published report, the estimated health care costs associated with falls in the European Union is €25 billion.

The ability to recover balance declines with aging, where older individuals often recover balance with a greater number of balance recovery steps and non-optimal stepping strategies. In addition, older adults have more difficulty recovering balance in the medio-lateral direction. The hip abductors are fundamental in controlling the motion of the body centre of mass in this direction during weight transfers of standing, stepping, and walking.

Furthermore, these muscles appear to be more susceptible to age-related composition and performance declines than other muscles of the lower limbs, especially in individuals at a higher risk for falls.

Unfortunately, common balance interventions, such as, functional balance training, Tai-Chi, or dance, have a very limited capacity to reduce the risk of falls in older adults. Interestingly, resistance training is relatively better than the mentioned interventions at reducing this problem. This may come about through mitigating the agerelated neuromuscular performance deficits. However, traditional resistance training lacks the emphasis in high velocity movements required for adequate fall prevention protective stepping strategies. Muscle power training is a safe and effective alternative to traditional resistance training. By emphasizing in maximum speed of execution, its results are often better than with traditional resistance training, especially in functional outcomes, with the potential to enhance balance recovery. However, there is little and inconsistent evidence on the optimal exercise parameters (such as velocity) for prevention of falls.

Community-based multi-component exercise programs are often used to promote health and functional benefits in the older adult population. These programs not only have a positive impact in a larger number of communitydwelling individuals, but can also lead to significant improvements. Nonetheless, these programs limited in reducing the risk for falls. Considering the robust effects of muscle power training in the older population, it is conceivable that a multi-component community-based exercise intervention, that focuses on developing muscle power and reduce fall risk, can improve the older individuals' ability to recover balance and consequently, bring greater benefits to the older adult community. However, there is no information on the feasibility of conducting an exercise program to develop muscle power and reduce fall risk in a community-based setting. Furthermore, it is generally unknown if such an exercise intervention can improve function, balance, and reduce the occurrence of falls in older adults especially, among those that have fallen in the past- which are the most relevant target population for both clinical studies and practice.