Boys saving energy for Guides! (5)
I believe the answer is:
leads
'guides' is the definition.
('lead' can be a synonym of 'guide')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for leads that I've seen before include "Guides from the front" , "stars" , "Takes initiative" , "Directs" , "Clues" .)