Chopin was not too frail to play his pieces. He was somewhat sickly some parts in his life, but lived fairly free of dibilitating sickness. He felt he had weaknessess in finger strengh, but who doesn't? I read a book on Chopin, and it said Chopin could play his pieces with out practice. When he would perform a concert, he would practice like crazy the other pieces (Bach, Mozart) that he was performing. He was considered a strong pianst at that time.