The most common and most likely answer to this crossword clue is the 7 letter word MUSCLED
I've seen this crossword clue in Independent
M
U
S
C
L
E
D
Buddy explains!
The straight part
We know that "probably having done a lot of working out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case probably having done a lot of working out = muscled.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MUSCLED mean?
MUSCLED verb- To use force to make progress, especially physical force.
- Bearing muscles or muscle tissue.
- Having large muscles.