Although I’m more of a proponent of downhill running at or slightly faster than race pace to improve muscle memory, here’s an example of how uphill repeats can improve your running.
When Allie Ostrander reached the final leg of the 2014 Nike Cross Nationals last December, she blazed over a series of hills and crossed the finish line of the 5K course in 17:19 to earn the individual title. The Alaskan native had her hometown hills–part of her strategic summer training regimen–to thank. They conditioned her to power through the short, steep inclines in the race’s final 1K.
Source: Peak Training: Summer Hills | Runner’s World