Comment by derefr

Just to be pedantic, an individual animal (or person) "trampling" something, would require that the top of the rise of their foot when walking, rises above the center-of-gravity of the victim, such that their foot or leg would impact the victim above their center-of-gravity and so knock them over, allowing the animal to then walk across the prone body of the victim.

Some extremely tall humans could manage to do this to a toddler, if they were kick-stepping, but most people could not. And nobody kick-steps their way around a park, anyway. People normally pick their feet up by only a couple of inches as they walk.

If you bump into a toddler when walking normally, the toddler's whole body will collide with your whole leg, and the toddler will falter backwards, maybe falling onto their ass, but not falling prone. And, crucially, the faster you collide with the toddler at speed, the further back they'd go — i.e. if you jogged into them, you'd end up punting them a good few feet away from yourself. While this would hurt, it'd be a distributed impact across their whole body, so it wouldn't cause huge damage. And it would give you the added reaction time to realize you just punted a child five feet and stop jogging.

"Trampling" by an individual animal is only really a big-animal thing. Elephants, giraffes, etc. These animals can trample a toddler without noticing, like you could trample a frog without noticing. But there are very few such animals. Even a draft horse would have to be galloping to manage to trample a toddler. Soldiers only get trampled in medieval battle by a single-rank charge of cavalry when they've been struck and are laying prone on the ground. Angry horses and cows only manage to trample people in their pens, if the person mistakenly thinks they should protect themselves from further kicks by getting low to the ground.

(I emphasize "individual animal" or "individual rank", as trampling works differently with herds of animals — you don't need to be kicked over, you just need to be knocked back; while this may stop the individual animal that collided with you, the animal is forced forward at speed by the rest of the herd, who all didn't experience the collision themselves, and so don't know to react to it; and so the herd will then flood over your knocked-back body, tumbling you each time until you do, by random chance, end up prone; at which point you'll be trampled.)

Being "ridden onto" by a tyre — whether a car tyre or a bicycle tyre — is very different, because the bottom of the tyre is pulling on the surface it's coming into contact with to propel itself forward. If a bicycle overmounts a toddler's foot at speed, the toddler will be pulled downward foot-first into the path of the tyre. Picture being caught by the roller barrel of a steam roller — with less weight, yes, but faster, grippier, and applied across a more narrow surface area.