I am a 74 years old man who while bicycling fairly extensively have lost most my calve muscles to the degree that I cannot tip toe. My left leg toes can be overcome by my hand pushing against them and I can hardly tip toe ( for a few seconds only using both legs.To rebuild those muscles I started 2 months ago walking one to one hours a day, climbing stairs and exercising tip toeing, but all with no noticeable improvement. I appreciate your helpful comment.