“The gym” had a completely different meaning in the 50’s than it does in the 21st century.
First of all, in the 50’s exercise was free. There was no gear or equipment of any type, you didn’t need a special outfit and there were no memberships involved. You could do sit-ups, jumping jacks and push-ups on your living room carpet. If you wanted to walk, there weren’t any treadmills about, you put on your coat and went outside. Want to up the pace? Walk faster.
No one was riding stationary bikes. They used the kind that get you from place to place. And they weren’t wearing spandex. T-shirts and shorts seemed to work. If you wanted to know how far you ran, walked or biked, your best bet was to follow up your workout by getting in the car, retracing your route, and making the calculation from your odometer.
There were gyms. They were open spaces of various sizes with hardwood floors and at least two basketball hoops. Most commonly you found them in schools. My grammar school had a gym with a low ceiling. I think that curtailed most of our basketball careers because we all starting taking jump shots with no arc.
The school gym was also the site of a 50’s favorites, dodge ball. If you are unfamiliar with this game it involved dividing the participants up into two teams and having them throw a ball at each other. If you hit someone, that person was out. If they caught your toss you were out. My gym teachers livened up the game by throwing three of four balls into the mix simultaneously.
There weren’t any other rules. If you hit someone in the head it wasn’t thought to be foul play, it was their fault for being inattentive. Aiming for the head wasn’t, however, good dodge ball strategy because it was too easy to duck away. I always went for the legs.
You could also reliably find a gym in a YMCA. And Catholic churches often housed gyms. The Catholics had already learned that a good place to play basketball was the most compelling thing they had to offer for a certain demographic. As with other areas of the church, the door was always open. No member card of guest fee required.