Stay in touch with the leaders (4,2)
I believe the answer is:
keep up
'stay' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for keep up that I've seen before include "Progress at same pace as others, or maintain appearance" , "Match pace or store aloft" , "' - - with the Joneses'" , "Stay with the pace, don't fall behind" , "Don't dawdle!" .)