The method of hill running not only builds strength to the muscles, but also power and speed. This added strength gives an added push-off and forward recovery of the leg muscles without the fatigue.
The hill training method is a more natural way of developing muscles rather than using weightlifting equipment. This endurance training will improve the ability of the heart to circulate blood throughout the body, which increases the amount of oxygen supplied to working muscles.
However, since hill running causes you to hit the ground harder as you come downhill, there is a greater degree of stress to the muscles and bones, which poses a greater risk for injury. It is therefore important to wear proper shoe gear with good stability and shock absorption.
Increasing flexibility is of the upmost importance in running as it will allow for a greater range of motion, allowing more ground to be covered on each stride, causing you to run faster. One of the greatest advantages of flexibility is that it allows the muscles to apply force more directly to the levers needed for efficient running, rather than against stiff tendons, ligaments and muscle tissue. The result is more efficient use of energy.
The hills will help you gain the speed for running your PR.