If you want to avoid injury and achieve maximum efficiency in your training, running up hill is the best routine for you, but make sure its fast, explosive and short. It is the best way to build leg strength because the fast-twitch muscle fibers are develop by running at maximum intensity. at least to start with, running uphill must be kept to 10 second bursts to avoid lactate and fatigue in the muscles. Running not more than 10-second repeats also reduces injury risk by limiting your fast-running time. Hill runs uphill can by their nature reduce the risk of injury because the slope decreases the distance you have to “fall” or land, thus reducing stress on the body. Studies have shown that sprinting uphill puts the muscles in constant overload and the nervous system working hard. It has the same speed benefit as track sprinting but is safer in some ways.