Flexibility is a “use it or lose it” aspect of aging.  As we age we typically get into certain patterns of movement.  We take the easier path to doing common tasks.  For example, instead of bending over to tie our shoes we sit down and bring the foot up to the hands.  Muscles which are not stretched become tight, which effects the movement of the joint.  In the case of tying shoes if we never stretch the hamstrings they get used to being in the shortened position.  This changes the movement dynamics of the joints affected by the hamstring and thus alters our overall movement patterns.  I include flexibility training in all client exercise programs.  My goal is to ensure that my clients are not limited in any range of motion.