Running form while training

Sometimes fast hiking is faster than running and has better economy. It also targets sligthly different muscle groups as you use while running. If you are training for an event where you will be hiking a lot, then you should even train the hiking. Do you use poles?

Not to cop out, but training both running and hiking are important – glutes are critical for both. But running and hiking have different gaits, where hiking does use the calves more. A critical question to ask is how much you hike versus run on uphills – this should dictate which you emphasise (as Thomas was indicating). That said, I consider them equally important, which includes as well the ability to rapidly transition back and forth based on both on variations in terrain and in racing strategy at particular points.
For training, on the tiny local ski hill (all of 47 m of vertical) I will do some repeats as runs and some repeats where I switch mid-way where the incline steepens a bit from running to power hiking (with or without poles). [Or at least will do them once the snow melts enough to leave an open track up.]