when you run and slide in your socks on a hardwood floor, which foot winds up in front?
Discussion
My brother made me do this test several times and it was moreso right foot than left.
Is this the same as standing and letting your self fall to the front. Your preferred leg will catch you.
There is also this trick with finding your preferred eye, don't know what it was exactly. Thanks for search engines: https://www.allaboutvision.com/resources/dominant-eye-test.htm