You have 'em. Do you use them?
Mine didn't work. I had a "hitch in my giddy up" as my PT guy put it. But really, my giddyup was gone and those glute muscles didn't quite know what they were supposed to be doing back there. I'd had a history of low back issues long before I was a runner and things had been off for a long time. I strengthened core and butt and found a PT who could address the issues and then I had to do the next hardest thing. I had to teach the glutes to work again. I've had glimmers.
Hill repeats. Take a short hill and run up it hard. No don't push off harder with your feet, extend your back leg instead and engage those glutes. When your foot hits the ground, feel that contact and pull that ground along making you go up. Voila! Glutes at work. I could only really do this for short bursts uphills. Then I'd feel my glutes tire quickly and I'd go back to the shuffling.
They weren't used to working at all. I could hear them whine: This is hard. I'm tired. Leave me alone.
With the PT's help, I've found the little tricks that keep my low back and hips aligned and happy. A quick roll on a foam roller for my low back and IT bands, a quick exercise to keep the hip upslip at bay (upslip = one side of the hip sits higher than the other). My mom has almost the same exact issue with her low back so I think it must run (snicker) in the family. I'm lucky that the running I want to do has forced me to address the issue and I found someone who could help. I hate to think of what my back would be like today if I hadn't done anything but sit on the couch. If I keep that upslip at bay, everything stays happy and my glutes miraculously start to function properly.
Another glimmer. We did a field test a couple weeks ago. One mile run hard over a cross country course. My glutes were burning on the uphills. This was completely new. I'd had my hamstrings burning, my lungs burning before etc. My glutes? Hunh. they must've been working and like usual complaining.
I'm starting to get it. Even when I'm running easily over flat ground, i can feel that grabbing action and my glutes engaged. I've gotten faster in the past month. coach has been having me do some shorter speedwork. It absolutely forces me to focus on my form. Glutes. Oh there you are!