Hi, Jan. I had been running for five years before I got my first nodule, then two more appeared after I ran the marathon. I do find that lots of walking and running makes the lumps sore, but you have to weigh that against the pleasure of doing things you love. I've actually switched to speed walking with MBTs instead of running mostly because the marathon damaged my knee. I'd still keep running even with Ledderhose, and you'll find other posts on this site by active people who say the same.