Not riding yet?
That's cool, me too.
Still need some fun.
Go run, run, run.
I know that's not that fun but it gets the job done.
Find a ledge and do some of those plyometric thingies these will certainly give you a nice tight bum.
Do some more.
So repeat some.
Rubber legs you will have and feel real dumb.
Bye bye, peace and always have fun!