Some athletic shoes have inflatable air pockets inside them. these air pockets act like springs that become stiffer as you pump up the air pressure. high pressure also makes you bounce back up off the floor sooner. why does high pressure shorten the bounce time?

Stiffer air pockets mean less distortion. More distortion takes more time

Explanation:

Distortion is the alteration of the characteristics of something. In this case, the characteristics would be the shape of the air pocket that is distorted when the shoe hits the ground with your weight on top of it.

If the air is at a higher pressure and it becomes stiffer, it would allow the air pocket to distort less on the impact. Less distortion would take less time to take place than a higher level of distortion.

this is poiselle's equation from fluid mechanic in physics. mech eng

it breaks and dirupture other materials and other sencews from the bottom