This dawned on me back when I was watching the world cup. All those L-shaped sticks with hinges in the middle carrying upper bodies around with speed and agility, when they should just fall over.
Imagine holding a severed leg and trying to kick a soccer ball with it. It would just flop around. Even if you freeze the joints, you're still trying to aim the crooked end of it to hit the ball just right. There's no way you're getting past the goalkeeper with that.
That's why people who think running isn't a skill are wrong. It's ALL skill. People who look at it as an effort never get anywhere, while fast people breeze past them with great form and no effort at all. Just instill the skill.