I've gotten a few questions from people about how effective I think knees are, how to knee in the most effective way, etc., so I thought I'd share my experiences on how to properly introduce some guy's unsuspecting balls to your friendly knee.

In short, kneeing is tricky. It's a lot harder to get the right angle with a knee than it is with a kick or a punch, and your room for error is smaller. If you connect with your thigh instead of your kneecap, it won't hurt much. If he's leaning…