As fit as a fiddle with meaning in best condition?

The phrase "as fit as a fiddle" means to be in excellent physical condition. It is often used to describe someone who is healthy, strong, and energetic. The phrase is thought to have originated in the 16th century, when the fiddle was a popular instrument. At that time, fiddles were made of wood and were very delicate. If a fiddle was not properly cared for, it would become warped or cracked, and would not sound as good. Therefore, the phrase "as fit as a fiddle" came to mean that someone was in good condition, just like a well-maintained fiddle.