Gym implements (9)
I believe the answer is:
Here is my best explanation:
I believe this clue is a double definition.
'gym' is the first definition.
'implements' is the second definition.
(Other definitions for exercises that I've seen before include "Works out", "Exertions to develop endurance or skill", "Keep-fit activities", "trains", "Activities to develop a skill", "Multiple repetitions to train" and "Muscle movements to promote fitness".)