Legend

 p = momentum m = mass v = velocity Fav = average force t = time

The impulse exerted by the punch changes the momentum of the recipient's head.  The gloves are heavily padded to increase t which decreases Fav of the punch.

Impulse

 The change in motion is proportional to the motive force impressed; and is made in the direction of the right [straight] line in which that force is impressed.  Hence, p is parallel to Fav and putting it all together symbolically, we have:Fav = p/t = (mv)/t The average net force equals the time-rate-of change of momentum.  It is useful to combine the force and time into a single notion that equals the known momentum change.  This concept of change in momentum is called impulse. Favt = p This is the measure of the force and the length of time that the force actually acts. Momentum, like gravitational potential energy, spring energy, etc. is a conserved quantity, as the Law of Conservation of Momentum states: total momentum of objects before = total momentum of objects after. Thus along with work and energy, momentum is an additional factor one considers when analyzing motion problems, particularly problems involving collisions or explosions. The pitcher exerts a force on the ball over as long a distance and for as long a time as possible.  The greater is Ft, the larger is p, and the higher the release speed.  Here the ball is shown every 1/100th of a second.  The greater the distance between images of the ball, the greater the speed.
 Momentum Inelastic Collisions