The most common and most likely answer to this crossword clue is the 12 letter word HEEL-AND-TOE
I've seen this crossword clue in Financial Times
H
E
E
L
-
A
N
D
-
T
O
E
Buddy explains!
The straight part
We know that "Walking method" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case walking method = heel-and-toe.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.