I'm trying to clarify something I hear about racing coverage during the tour de france.

Sometimes they'll talk about someone trying to break away and then some other rider from another team will chase them down, stay on their wheel, and "drag them back".

Does this mean that having someone right behind you, assuming you are in front, slows you down (as opposed to race cars where the front car still benefits some)? And, if this is so, does it only apply when one person is behind you, but not if you are leading a large group?

Bob