Others adopting physical exercise about to get appreciation (7)
I believe the answer is:
respect
'appreciation' is the definition.
(I've seen this before)
'others adopting physical exercise about' is the wordplay.
'others' becomes 'rest' (I've seen this before).
'adopting' means one lot of letters goes inside another.
'physical exercise' becomes 'pe'.
'about' becomes 'c' (abbreviation for 'circa'**).
'pe'+'c'='pec'
'rest' enclosing 'pec' is 'RESPECT'.
'to get' acts as a link.
(Other definitions for respect that I've seen before include "relation" , "Due regard; admiration" , "Admiration or esteem" , "Pay attention to" , "High opinion or regard for" .)