Since many forum members are also into juggling, thought I'd share an interesting 2-page article in the latest issue of
Physics Today...
Botvinick-Greenhouse, Jonah, and Shinbrot, Troy, 2020,
Juggling dynamics, Physics Today, v. 73, p. 62; doi: 10.1063/PT.3.4417. I can view it online at
https://doi.org/10.1063/PT.3.4417, but that link might only work for subscribers.
(You know you're a hopeless nerd when
Physics Today is your favorite magazine.)
The central question: How can a speed-juggler catch a new ball every 120 ms when the reaction time of a highly trained human is 200 ms at best?
Short answer: Nobody knows for sure, but 2 features of our neurophysiology may help...
1. Our inner physicist: Human and monkey brains seem to be able to compute accurate parabolic trajectories from an internal representation of the relevant laws of motion.
2. Muscle memory.
Similar considerations may bear on advanced throwing top tricks, but there you have the added complication of string control. Hard to imagine that your inner physicist carries around equations of motion for something as physically perverse as flying string.