i'm unsure of your statement, but i believe that the statement is false. A rake would add more physical activity, since you're using both leg muscles while walking, and arm muscles.
Secondary bacterial infections is bad for any body but even worse for elderly because there body can't fight it off because there bodies are wore down the human life cycle is kinda like a car you by it brand new then as it gets older it starts to brake down and ware out then it finally brakes down for good