Fostering functional capacity comprises promotion of functioning, prevention of functional decline, rehabilitation of functional losses, and compensation for functional deficiencies. The levels of functioning include organ level, person level, and person-environment relationship, which also comprises participation in different life situations. The functional levels are useful to consider for disablement as well as for re-ablement and in the context of rehabilitation. The functioning of organs, such as muscles, changes with increasing age; however, resistance training can counteract age-related decline. With increasing age, deficits may occur in multiple systems requiring more complex approached in restoring functioning. Finally, it may become necessary to employ compensatory strategies.