The term EXERCISE OF A SORT can be broken down into two crossword solutions: ETUDE (5 letters) and KNEEBEND (8 letters). An etude is a short musical composition, usually for the piano, that is designed to provide practice in a particular technical skill. It is often used as a teaching tool to help students develop their technique. Kneebend is an exercise that involves bending the knees while keeping the back straight. It is often used to strengthen the muscles of the legs and core.