Why Is This Man Showing Leg?

I have a confession to make. I'm 56 years old and I've never been bowling. I've never even been in a bowling alley. I've seen people bowl on television and in the movies, which allowed me to recognize the bowling score card the man is holding, but I have no idea how to keep score. So why is this man showing leg? Is it part of a bowling ritual? Does the loser have to show off a shapely calf? Or maybe it's the winner that has to flaunt a little skin. Or maybe he rolled a zero and was trying to make an excuse. "Look, I hurt my knee on the back swing, and that's why I didn't hit anything." Written on the back, "Roy Scocu 1/20/53"