Last Tuesday I had to walk down 12 flights of stairs in a high-rise office building because the Lifts suddenly went out of order. Well, I had to “pay” for that later, in terms of my leg muscles being very sore for two to three days afterward. I was not happy. I work on 2 floors having to go upstairs and downstairs (or use the Lift if it is working) many times a day and a week.
After this temporary muscle strain, whenever I went downstairs, my calf muscle in one leg or the other or the muscles in my upper legs on the front hurt. Apparently, walking down the stairs causes more strain on the calf muscles, than does walking up the stairs, because it requires more force to control the muscles in a downward movement, than going upward when the momentum of your whole body helps exert the force for your muscles to help propel your legs!