As an athlete I always searched for ways to train harder without beating up my joints. When I came across hill sprints, it was not too long until I realized I was on to something. Hill Sprints get your heart and lungs rev'd up with less stress on your joints and muscles compared to flat surface sprints. Most athletes take a huge beating at their daily sport or weight lifting seasons so I believe methods like these are golden. Not only they are safer on the joints due to the incline but less muscle break down occurs due to the concentric nature of hill sprints (assuming you are sprinting up Hill). This means less delayed onset muscle soreness will be experienced after this workout.
Dagestan, which is a Northern location in Caucasus mountains in Russia, is home to many of the olympic gold medalists in wrestling. It is also known for it's mountains and hills. Dagestani wrestlers are known for performing an old warrior ritual which consists of gathering every morning at a bottom of a mountain and running all the way to the top which is about a couple miles. This has been a staple of their workouts and is a ritual they performed for centuries. Hill sprints were also practiced by athletes like Jerry Rice and it is no coincidence hill sprints became very popular lately.
One down side of the hill sprints is that it can make you slower since you are getting accustomed to working at slower speeds. I usually incorporate hill sprints earlier in the competition preparation programs and take slowly decrease the frequency of the in programs closer to competition.
How to Perform Hill Sprints:
Once you find a hill, make sure to warm up and wear cleats if necessary. Once you are warmed up, slowly start at the bottom of the hill and instantly increase your speed and go all out all the way to the top. Slowly walk down the hill and repeat. Depending on the length of the hill, start with 3-6 rounds and try to increase the number of rounds each season. Stop performing the workout if your technique is becoming sloppy and make sure not do this workout more than twice a week. Note that, longer sprints improve power endurance and shorter ones improve maximum power output. It is best to combine short and long hills in your regimen.
Be safe and have fun.