Book 28, Question 22
Why does pulling your hands back help you catch a fast ball?
When a ball hits your hands, it has to stop.
If you keep your hands stiff, it stops in a very short time and the force is large, which stings. If your hands move back with the ball, it stops over a longer time, so the force is smaller. This is the same idea behind air bags and padded landings. Good catchers give with the ball.