TO STAY SURE-FOOTED—KEEP UP YOUR MOBILITY I’m sure you, like me, have noticed your muscles getting a little stiffer over the years. And you probably don’t feel as flexible as you did when you were younger.   However, not being flexible directly affects our mobility. Mobility can be looked at in a couple of ways: There is joint mobility, which is moving a joint or a group of joints—such as your hips or shoulder—through a full range of motion. And then there’s total-body mobility or how your body moves as a unit. For that you need multiple body parts to work...