There have been several advanced training courses for personal trainers to continue their education confidently extend  their services to seniors. Seniors that incorporate a fitness regimen as part of their lifestyle can experience several benefits such as improved balance and coordination, increased strength, improved endurance, and most importantly improved confidence and quality of life. Regular physical activity not only slows atrophy and increases bone density, but it could also help speed up recovery from surgery, according to the American Academy of Orthopedic Surgeons. Please see the article below for additional information. 
Article by Mindy Caplan 1/8/14