You can do Poorman's Roman Swings. You need a five gallon bucket, with a thin wire handle, filled with concrete. Put the handle between your big toe and the next toe. As you lift the bucket start hopping and then begin to rotate. Eventually the bucket will be swinging in a big arcing circle as you rotate around in one spot on one leg. (It's a little tough to get used to.) Do one minute, stop and then switch legs. Builds tremendous upper leg and big toe strength. Your legs are your base, your foot is the base of your leg and your big toe is the base of your foot.