What constitutes a Hill?

Since the garmin and I are on a break, I have been playing around with a few things the past month (in hopes of keeping myself entertained and sane during these hot summer months). So one thing that I have been focusing on, due to its weakness in my previous training cycles and just training in general, is hills.

In living in the lower mainland of BC, one doesn't have to run far to encounter a 'hill' of some sort. But all hills are different so I suppose my main question, is what kind of elevation gain classifies a hill as being useful for hill training? I know that for me, with starting out, the hill can't be a mile plus of straight incline (yes, Whatcom 'Hill', I'm talking about you). The elevation gain is far too great and too long for  my legs to start out on, and with little to no breathing room to recover I find it mentally and physically overwhelming and defeating.

Thankfully, I have a hill by my house that for right now is a good first step in this hill training process. The roads are set up in such a way that it is a 1.15 mile loop (thanks Map My Run) with a .25 mile flat stretch, and an elevation change of 70 ft. I like this hill because it's short, a loop (which naturally, you don't look as crazy running a loop multiple times in comparison to up and down a hill... right?), and has a flat stretch that allows a small break and recovery stretch to stretch the legs out and find my rhythm again.

Now whether or not this is what a hill work out looks like I have no idea, but right now I do a small warm up and then hit up this hill. Last night I did the hill loop twice, cooled down and then stretched my legs out in hopes of preventing things from getting tight or sore... This morning my butt is definitely reminding me of the hills and lunges I did yesterday (yesterday morning I attempted to go for a run, didn't work so as punishment I made myself do lunges in the catwalk... ever notice how long catwalks are! That thing was never ending). So for the first time, in quite some time, my body is sore, in a good way. Its nice to wake up and be reminded of a previous days workout, it makes me feel like I'm improving again or working towards something, even if I'm not too sure what it is.