What sorts of things?
Inability to run?
Inability to bend down?
Sorry, I need specifics - I should have made that clearer
I do not exactly recall the specifics of the medical I went though for my previous job of station staff, but from what I recall, there was a BMI assessment (height/weight), drugs and alcohol sampling, hearing test, eye test and colourblindness test.
I do know whilst on the job that there was plenty of bending down to pick things up off the floor, carrying of heavy suitcases and wheelchair ramps, and pushing wheelchairs (sometimes I had to push a wheelchair and carry a heavy suitcase at the same time!)
A mobility assessment I did for the company I work for now involved walking across a piece of dummy track, reading something from a wall (similar to the eye test you do for driving lesson; reading a number plate across a car park) and a colour test, being shown green, yellow, red and white signals on a handlamp and having to identify them.