Originally Posted by tjspiel

Think about how people sit when they're not on a bike. If somebody has to sit on a stool or bench (something without back support) for any length of time, what to they often do?

If there's a table or bar in front of them, they'll lean forward and rest on their arms!

Even if there's no table many people will lean forward with their elbows in their laps to help hold their back and head up. Even if there is back support, most will shift around unless fairly well reclined. Watch how people sit at a stadium. You won't find many that sit in the same position all the time. Sometimes, they'll lean back. Sometimes they'll sit bolt upright. Sometimes, they'll lean forward.

That's what's nice about a bike with drops. You can rest the various muscles used to hold your torso and head up by changing your position.

Originally Posted by donnamb

Yes and no. I think they achieve a similar objective, but not quite in the same way. Behold this nifty diagram shamelessly lifted from tfahrner's blog.