Well, I've never kicked anyone even half as hard as I could (and hope to never have to), so I can't really argue the point. I have dropped people and intentionally knocked them back, and the ones who went straight down were the ones in the most pain.
Wow a name like IronFoot kinda suggest otherwise,lol. I only ever used this once in actual self defense. I dont think I used full power even, as I was trying to land it as fast as possible. With that said, it ended the fight immediately. He went straight down and stayed down.Four ribs broken.
If your partner or instructor says you arent getting enough power on a snap kick then you are probably trying too high. lower the kick, like Zach suggested.