Do such classes prevent you becoming a square peg? (4,3)
I believe the answer is:
keep fit
'becoming a square peg?' is the definition.
I know nothing about this answer so I can't tell whether this works.
'do such classes prevent' is the wordplay.
I cannot quite see how this works, but
'prevent' could be 'keep' (keeping is a kind of preventing) and 'keep' is located in the answer.
The remaining letters 'fit' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'you' is the link.
Can you help me to learn more?
(Other definitions for keep fit that I've seen before include "Callisthenics" , "Do physical exercises?" , "Exercise designed for physical wellbeing" , "sort of exercise" , "Maintain health" .)