Do they exercise their elbows as they run? (7)

'do they' is the definition.
The definition suggests a plural noun which matches the answer.

'exercise their elbows as they run?' is the wordplay.
I cannot quite see how this works, but
'run?' could be 'jog' (jog is a kind of run) and 'jog' is found within the answer.
The remaining letters 'gers' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?