It’s a natural instinct to try to break the fall. Doesn’t work of course.
This is why professional bicycle racers do tumbling exercises during the off season. If you’re going down, gravity will inevitably win. Tumbling exercises conditions the person to tuck and roll instead. Worked for me once in a mountain bike race and twice at the velodrome.
I’ve had a few low back surgeries that weren’t fully successful. The first one left my left ankle super weak but after some years I was able to gain some strength back as the nerve regrew. The second surgery did the same thing to my right ankle but I don’t think I’ll be getting it back like the left one. I’ve fallen a few times but luckily I was able to remember to twist and fall on my upper arms rather than try to catch myself. More embarrassment than anything.
Back in the 80’s I was riding a motorcycle that went out from under me on a sweeping curve. I was fine rolling along until I got the bright idea to put my arms and hands out to stop my roll. That’s when the road rash got me. Live and learn I guess. Never did see anything on the road to cause the tires to slip out. No gravel, oil, or water. The bike was fine so I picked it up and rode on.