I'm not so sure about that... what if you're a disabled person?
What if you started giving free tickets to people who can do 60 sit-ups, or 100, instead of 30? Wouldn't this mean free tickets for men only (or mostly)?
So give the disabled people a free ride (which, YMMV, they should be getting anyway and actually are already in Germany)
As for the men-only part... enhance the system to not use a fixed number but have that number depend on the applicant's estimated gender, age, weight etc.
You could even gamify this, gain money from selling people's user statistics (ugh!) etc.
> 60 sit-ups, or 100, instead of 30? Wouldn't this mean free tickets for men only (or mostly)?
Why would you think that? Body weight exercises are generally easier for smaller built people to get good at. For one, it gets harder and harder to add more muscle as you get bigger, and secondly smaller built people have shorter distances to move. If it was limited by explosive strength, maybe, because it's harder for women to grow large muscle volume, but if you can do 10-20 plus, it's pretty much down to endurance beyond that point.
You alter the activity for different disabilities. Someone unable to use their legs could do some lifting. Someone unable to use their legs or arms could do some encouraging yelling to other people.
Don't let diversity scare you away from doing things - do them, but make best efforts to be inclusive.
What if you started giving free tickets to people who can do 60 sit-ups, or 100, instead of 30? Wouldn't this mean free tickets for men only (or mostly)?