Excerpt from letter she wrote her mother:

Swimming was great yesterday. I didn't swim much better, but there were a lot of kids from my class there. When the others all left at 3:30 p.m., we all went into the pool with the shallow water and played: ball, pull out, pull through, pull through, etc. Today I finally had lessons with Mrs. Müller again. She recognized me right away and said I had grown a lot and sends her best regards. Because she didn't have time to go into the lake, I swam in the pool on a loose line. I think today was better. [1]

Notes:

[1] My speculation was that swimming was one of the things that Mom did to help in her polio recovery, but somehat unclear from Mom's memoirs exactly when in 1932 she contracted polio. Obviously, she grew to like swimming a lot.