Soldiers' brisk jog (7)
I believe the answer is:
refresh
'jog' is the definition.
(thesaurus)
'soldiers' brisk' is the wordplay.
'soldiers'' becomes 're' (I've seen this in other clues).
'brisk' becomes 'fresh' ('fresh' can be a synonym of 'brisk').
're'+'fresh'='REFRESH'
(Other definitions for refresh that I've seen before include "Renew" , "Breathe new life into" , "Invigorate -- her serf (anag)" , "Give drink to" , "Restore strength and vigour as with food and drink" .)