A toddler's tiny mass, along with a rubbery and flexible body, allow them this luxury. An adult's mass quickly runs afoul of the above mentioned physics-gut-check.

That greatly depends on the surfaces involved and the persons skills.

I’ve fallen off the back of a galloping horse before as an overweight 6+ foot guy and been fine, but that frequently causes severe injuries. I doubt a one wheel rider is dealing with significantly more energetic collisions. They are however dealing with the dangers of urban environments.

I’m actually curious how the physics works out on this one.

Excess body fat is going to act as additional padding, but it’s also additional mass going into the collision equation.

I wonder where the sweet spot is?

I’d wager the primary factor is how you land, whether you hit your head, etc. If you land on your buttocks first it likely wouldn’t be as bad as landing flat on your back and striking your head. Although getting that much shock/compressive force applied to your spinal cord probably isn’t great either.

Replace body fat with muscle mass and you'll have found the sweet spot. Muscles need to protect and hold everything together to protect them from shock. They also provide more of a barrier.

Body fat is just extra weight, it's not going to hold up anything.

I'm convinced that Fat is just a tax on the body.

Unless you are an aquatic mammal. Or a human that loves to float.

The gamut of human capability when crashing vehicles is SO MUCH larger than most people realize. The average bike commuter probably has a much higher chance of injury in a solo crash than someone who's skated for decades on a onewheel. When I see discussions of safety I rarely see "get good at crashing" brought up, but it's such an important skill.

When I ride my bike I'm always hopping up curbs at speed, doing quick whip skids/ted shreds etc, not just because it's fun, but because those are the skills you need to stay alive in abnormal situations. It's honestly kind of baffling to me that most people don't actively work on expanding their safety envelope.

You can get good at crashing, and at avoiding crashes, and when you do you can either do the same things safer, or do more fun things with the same level of safety. This is why Alex Honnold isn't dead (yet).

> The average bike commuter probably has a much higher chance of injury in a solo crash than someone who's skated for decades on a onewheel

what of the average onewheel commuter?

I can ride a bicycle in the Netherlands (haven't crashed since I was a child) but you couldn't pay me to ride in London.

I rode in London, a lot. Fast, too. Couple of accidents, once slipped off a pedal it speed, ran over my foot, but stayed on (thanks, physics), once got too close too a rising curb and couldn't steer, hit a fence at speed, got deep cuts and lots off bruises, but bike took most off the damage. Have had accidents since, usually from heavy breaking, with complication leading to launching over the front. I cannot see how these boards could be safer, any dismount at equivalent speed would need considerable skill to not face plant, and any complications would just add energy too the impact. That or you could simply quail too stop in time and hit something (like a car door opening, or a truck pulling out, or that kid/dog that ran in front of you)

I've only crashed once in Copenhagen, when a tourist turned left directly from the right side of the lane.

Oh, and once when I was so drunk I fell off 2 seconds after getting on the bike.

In London it's necessary to plan a quieter route, using roads most people don't even realise exist. It can't be as nice as the Netherlands, but it can be OK.

I think your chances of ever encountering a truly abnormal situation on a bicycle (that you couldn’t get out of with knowledge of how to use your brakes) is not something that happens to most people even once in their lives.

I once took a bike safety class that included practicing "quick turn", "rock dodge", and rapid braking. (I guess the last is included in "how to use your brakes".)

I'd like for my skills at each of these to be better than they are today, and I ride my bike quite a bit.

> When I ride my bike I'm always hopping up curbs at speed, doing quick whip skids/ted shreds etc, not just because it's fun, but because those are the skills you need to stay alive in abnormal situations.

I've cycled to work for 15 years, and I've never hoped up a kerb and I don't even know what a whip skid / ted shred is.

> I've cycled to work for 15 years, and I've never hopped up a kerb and I don't even know what a whip skid / ted shred is.

My commuter e-bike weighs a solid 80lbs fully loaded. I'm not hopping curbs or doing "whip skids" on it. I basically ride it like a touring motorcycle.

I used to commute through London by bike. Like the cliche I was I ended up riding a fixie (everything else either got stolen or broke).

I found through trial and error that riding aggressively was safest, not because it was inherently safer but because everyone would take note of the idiot hooning around too fast and take extra caution. Of course the failure mode here is when someone doesn’t notice you…

Years later I now commute by bike in Cornwall where the local population is ignorant of cyclists. I ride an electric cargo bike with my son on the back and I’m incredibly conservative.

There’s no real difference in incidence of accidents, but incidence of “near-miss” and severity of possible accident? Hands down riding conservatively with no hopping around is safer. Duh! ;)

Have you gotten good at reacting to a firmware failure that suddenly and drastically changes the handling of your bike? ;-)