Hill repeats are repeated short segments of hard uphill running. They increase aerobic power, high-intensity fatigue resistance, pain tolerance, and run-specific strength. The ideal hill on which to run hill repeats features a steady, moderate gradient of 4 to 6 percent. Hill repetitions are typically done at the end of the base-building period as a relatively safe way to introduce harder high-intensity training into the program.
Example: 2 miles of easy jogging (warmup) + 10 x 45-second hill repeats at a hard effort with 2-minute jogging recovery between reps + 2 miles easy jogging (cooldown)