Question

Why does a cricketer pull their hands back with the ball while taking a catch?

Answer 1

A cricket player moves his hands backwards on catching a fast cricket ball to prevent injury to the hands.
Reason:
--->A fast moving cricket ball has a larger momentum.The momentum of the ball has to be reduced to zero in order to catch .
---->When cricket player moves his hands back ,  the time taken  to reduce the momentum of the ball to zero is increased.
----> Due to more  time taken to stop the ball, the rate of change of momentum of ball is reduced and hence a small force is exerted on the hands of players. So, the hands of player do not get hurt.
--->If the cricket player stops the fast moving ball suddenly, then large momentum of the ball will be reduced to zero in a very short time , due to which the rate of change of momentum of ball will very large which will exert a large impact force on player's hand causing the injury to his hands.

Conclusion:
To prevent injury to his hands, always a  cricket player moves his hands backwards on catching a fast cricket ball