This hill fartlek workout is designed to challenge different energy systems and improve both strength and speed. Warm-up properly by completing the light jog for 5-10 minutes, as well as the dynamic exercises. For the main set, find a hill with a moderate to steep incline, which is long enough that you will be sprinting for approximately 20-40 seconds. After sprinting, slowly walk back down the hill and start again after approximately 2 minutes of active recovery. Repeat 6x times.