Exercises before small drinks (5-3)
I believe the answer is:
press-ups
'exercises' is the definition.
(press-up is a kind of exercise)
'before small drinks' is the wordplay.
'before' becomes 'pre' (prefix meaning 'before').
'small' becomes 's' (abbreviation - e.g. clothes size).
'drinks' becomes 'sups' (to sup is to drink).
'pre'+'s'+'sups'='PRESS-UPS'
(Other definitions for press-ups that I've seen before include "Exercises done facing the floor" , "Exercises performed face down" .)