I feel nauseated just imagining what it would be like to land on my knees without any sort of padding. Ugh, brings me back to when I was a kid and I’d fall off my bike or scooter and have a purple knee for days with a giant gash in it lol.
I'm an old guy just learning to ride an electric skateboard and used the tripple8 pads in this video. I fell on the pavement with enough forward speed to slide the elbow pads up, exposing my elbow and forearm to pavement. I lost a lot of skin and damn did it hurt! I'm now upgrading to beefy motocross pads, which looks like riot gear armor...
Judging by RU-vid videos and the local skatepark, Scooter Kids like the largest knee pads available, regardless of whether they're going to stay in place or not!