I have seen a 67 yr old grampa who could barely pedal uphill only stop 4 times down clownshoes and didn't have a problem with the skinnies.
On the same ride, his grandson who is only 13 was falling off all the skinnies and flailing everywhere.
Grampa = physically out of shape, barely breaths out of one lung.
Grandson = physically tip top shape. Runs 5km every night with dad and swims/rides every second day.
Constantly, just like other sports (surfing, motox, skateboarding).. the mental aspect is always there.
Practice and dex. skills is in your head based on experience.
That is mental. Not physical.
When your brain knows what to do, your body follows.
80 % mental
20 % physical