Back to the fore. It is a very common phrase in the Spanish language and it does not mean anything other than to return to the ring, to return to the daily struggle, to work, to study, to whatever activity we do. But the word gym it implies a certain struggle, a certain effort, a certain problem. It is a word of Greek origin, one of the many words of Greek origin that we have in Spanish.
In Ancient Greece the arena was the fighting school for sports that did not require very open and wide spaces, for example wrestling or boxing. It could be part of a public gym or function independently. The arena occupied an important place within the society of the greek polis because it was the place where you got, along with the gym, the physical beauty that the Greeks adored so much. Here men became athletes and over time, as is often the case with spaces where many people gather, it became a place for debate and social political discussion.
One arena followed a certain plan: it was rectangular, in the center there was a patio surrounded by rooms that had different functions: changing rooms, bathrooms, classrooms, etc. There was a covered portico to shelter from the rain and wide corridors, as can be seen in the ruins of Delphi and Olympia. Did you know?
More information - What to see in the Archaeological Museum of Olympia
Source and photo - Wikipedia