drop behind vs drop back

drop behind and drop back both are verbs.

Word	Noun	Adjective	Verb	Adverb
drop behind	No	No	Yes	No
drop back	No	No	Yes	No

As verbs, drop behind and drop back are synonyms defined as:

Other synonyms of drop behind include drag, get behind, hang back, trail.

drop behind (verb)	drop back (verb)
to lag or linger behind	take position in the rear, as in a military formation or in the line of scrimmage in football
	to lag or linger behind