Jut walking for health proves valuable.
Tennis Walking
Tennis Walking is a way of walking while practicing. You don't have to run for balls that are out of reach of a walk. Look at older players and you'll often see that they don't run or even jog but rather limit the balls they reach by how far they can walk to reach a ball.
Another approach to this is a toss and hit method of solo practice when you don't have a backboard. Just toss the ball to the maximum distance you can move and reach it on one bounce while walking.
