Run to second reproduction (6)
I believe the answer is:
sprint
'run' is the definition.
(I know that sprint is a type of run)
'second reproduction' is the wordplay.
'second' becomes 's' (common abbreviation).
'reproduction' becomes 'print' (I've seen this in another clue).
's'+'print'='SPRINT'
'to' acts as a link.
(Other definitions for sprint that I've seen before include "Quick dash" , "Short fast run" , "Run rapidly" , "To make fast progress" , "quick run" .)