A gymnastic exercise (5-2)
I believe the answer is:
press-up
'a gymnastic exercise' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for press-up that I've seen before include "Face-to-the-floor exercise" , "Keep-fit exercise" , "PE exercise" , "Arm exercise while lying face down" , "Form of arm exercise" .)