Increased muscle fiber endurance can be affected by

...the type of activity performed.

To get better  muscle endurance you need to exercise those muscles.
There are two types of increase: increase of the size of the fibers or a increase in the number of fibers (it's when the muscle fibers divide).  Either way, both this methods need training.

eating a diet rich in fibers, such as whole grain foods and oats. It can also be "affected" consistent daily exercises that strengthen and tone muscles.

The photon striking the atom is moving too fast.

Explanation: