Relying on glutes, hamms and quads

I will start working on my speed on the short runs. Reading other blogs has made me faced the fact that I don't use my tights while running !!!
Run 4 miles, average 10, best 7.25, cal 471, RPE 7, MR 160-171, Time 39.58
I will have to learn to push on those muscles. Squeeze them. I started today and I was watching all the time that I don't do it ever. All the time I had to be remembering myself that using them was about to rise them, to switch muscles and to bounce softly on my knees, of course this forced me to bread stronger, but not into a bad point. I assume the fact that after running for three years I should be some prepared to increase strength and improve some my speed. By consequence I am not working either on my VO2. I don't know how far I can go!!
While avoiding to be injured and because as increasing speed was painful on my shines, since last year I've been working on a slow pace which doesn't sound enough challenging on my side. Still I remember K.I.I.S.
It was a very good run, after it 30 minutes stretching session appear to have had helped a lot.