The benefits of hill training are as follows
a) Increases aerobic capacity that enables you to use less oxygen at increasingly longer distances.
b) Improves the running economy that enables you to use less oxygen to run at a faster pace.
c) Increases your stamina that enables you to run farther at a given pace.
d) Builds strength in your gluteals (buttock), quadriceps (front of thigh), gastrocnemius (upper calf), and soleus (lower calf) muscles.
e) Improves your stride length (from uphill running) and your stride frequency (from downhill running).