From Degrees of Bizarre Lewdity Wiki

The gym is a special location added by the mod where you can increase fighting and athletics skills. It is located on Cliff street. The entry fee is 50 pounds, upon first entry of the gym you will be faced with this screen

You are in the gym. Here you can pay to improve your physique or athletics, either by yourself or with the help of a trainer. Asking for a trainer is more expensive, but the results improve significantly. Entries cost £50 per day and personal training costs £15 per session. There is also a set of stairs going up somewhere.

(The gym is not much populated yet. Not much people like to wake up early on the weekends.)That is one possible gym scenario which differs according to day of the week and time.

(1) Workout by yourself (1:00) | + Fatigue | + Physique

(2) Do cardio by yourself (1:00) | + Fatigue | + Athletics

(3) Call for a personal trainer (1:00) | Costs £15 | + Fatigue | + Physique | + Athletics

(4) Investigate upstairs (0:01)

(5) Changing room (0:01)

(6) Leave

After choosing the fourth option you are greeted by: You slowly climb up the stairs and, once at the top, you see some people dressed in eastern clothes, wearing colored belts and making weird noises. "Why hello there, young grasshopper," says an elder man, "I can see you are new here. Here is where honored warriors come to refine their body and mind. Welcome to the Dojo. Feel free to come and train with us anytime. And do not worry about my eerie-looking students, they have been very well disciplinated". "Sensei," says one of the students, "I need help with this new movement..." and so the great mantis goes back to teach the young grasshoppers.

(1) Okay

You are in the Dojo upstairs of the gym. Here you can acquire fighting experience and strengthen your willpower.

(1) Train (1:00) | + Fatigue + Fighting | + Willpower

(2) Leave