I can remember running along next to this crater. It seemed I could run forever on the Moon and my legs would not get tired. There was a reason, however. On Earth, I weighed about 150 pounds and suit and backpack another 150 pounds. On the Moon, with its one-sixth gravity, my equipment and I only weighed a total of 50 pounds. This light weight made me feel as if I were super strong - that I could run forever.

An astronaut learns very quickly to run in a space suit. The suit is stiff and hard to move at the knee and hip joints, but moves easily at the ankle joints. Moving about is most readily accomplished by keeping the legs relatively stiff and using mostly ankle motion. It feels and looks as if you are dancing on tiptoe. If I could bring that one-sixth gravity field back to Earth, I could win the Boston Marathon and never even get tired. And why not? My legs would only have to carry 25 pounds.