Substantial proportion (in the range of 6% to 25%) of free-living individuals, who are 65 years old and even older, suffers from many aspects related to the syndrome of frailty. Although the syndrome is complex and still lacks a standard definition, there is a growing consensus about the signs and symptoms. Patients who are afflicted with frailty typically exhibit losses of muscle strength, fatigue easily, are physically inactive, with an increased risk (and fear) of falling, have undergone a recent, unintentional loss of weight, experience impaired cognition and depression and, is frequently complicated by a variety of coexistent illnesses. In this context, functional tests to predict discapacity and frailty are needed. Accelerometry offers a practical and low cost method of objectively monitoring human movements, and has particular applicability to the monitoring of disability in aging population. Accelerometers have been used to monitor a range of different movements, including gait, sit to stand transfers and postural sway. On the other hand, it is important from both scientific and practical points of view to examine to what extent older people could minimize age-related losses of muscle mass, strength and power due to strength training. The benefits of maintaining or improving strength and/or explosive strength production of the neuromuscular system in aging people include correction of gait disturbances, prevention of falls, improved stair climbing and walking, and increased mobility, as well as improved performance of activities of daily living. Ongoing resistance training may also serve to delay the threshold for dependency by several years and. can be utilized as preventive, therapeutic, and rehabilitative tools to optimize neuromuscular function.