Historians frequently:

• Sit for long periods of time.
• Repeat the same movements.

It is important for historians to be able to:

• See details of objects that are less than a few feet away.
• Speak clearly so listeners can understand.
• Understand the speech of another person.

It is not as important, but still necessary, for historians to be able to:

• See details of objects that are more than a few feet away.
• Focus on one source of sound and ignore others.
• See differences between colors, shades, and brightness.
• Use stomach and lower back muscles to support the body for long periods without getting tired.