ID:140062
 
Code:
mob/proc
End_Sit_Ups()
winset(src, "sit_up_metre","is-visible='false'")
src.client.screen -= /obj/training/Sit_Click // <--- This one!
src.is_training = 0
src.icon_state = ""
src.moving = 0


Problem description:

The line stated isn't taking effect, Everything else there is working.
Because /obj/training/Sit_Click is a type path, not an actual object. You will need to use locate() to find an instance of an object to remove.
In response to Garthor
Thanks, I got it. :)