Adult entering short run gets injury (6)
I believe the answer is:
sprain
'injury' is the definition.
(I know that sprain is a type of pull)
'adult entering short run gets' is the wordplay.
'adult entering short' becomes 'spin' (I am not sure about this - if you are sure you should believe this answer much more).
'run' becomes 'ra' (I've seen this in other clues).
'gets' is an insertion indicator.
'spin' placed around 'ra' is 'SPRAIN'.
Can you help me to learn more?
(Other definitions for sprain that I've seen before include "Wrench (an ankle) 6)" , "Wrench (ligaments)" , "Wrench or twist" , "Injure a joint by twisting its ligaments" , "Twist ligament(s)" .)