Need your help. Female - 48, personal trainer, grp fitness instructor and healthy (some low back pain due to bulging disc).  I think I’m over training my glut med and min and can’t seem to get the max involved. Even though I teach 4 night a week step conditioning and yoga - I still try to maintain my own workout at least 1-2 days a week at home. Somehow (I know how), I have over developed my glut med (mostly on my left (sore back) side).  Now I feel like everything I do (lunges,squats), just makes the glut med and min stronger and my butt looks and feels NO DIFFERENT. Need some help. I want a stronger BUTT (and the sore tight glut med) to relax some. (I have tight hip flexors and walk with my feet out like a duck (working on correcting it) and a weak mid section though I work core and abs as prescribed.  Even when I do , leg ext and curls I feel a dynamic tension in the glut med. Thanks - Patty

Have you tried hyperextensions and reverse hyperextensions?

Need your help. Female - 48, personal trainer, grp fitness instructor and healthy (some low back pain due to bulging disc).  I think I’m over training my glut med and min and can’t seem to get the max involved. Even though I teach 4 night a week step conditioning and yoga - I still try to maintain my own workout at least 1-2 days a week at home. Somehow (I know how), I have over developed my glut med (mostly on my left (sore back) side).  Now I feel like everything I do (lunges,squats), just makes the glut med and min stronger and my butt looks and feels NO DIFFERENT. Need some help. I want a stronger BUTT (and the sore tight glut med) to relax some. (I have tight hip flexors and walk with my feet out like a duck (working on correcting it) and a weak mid section though I work core and abs as prescribed.  Even when I do , leg ext and curls I feel a dynamic tension in the glut med. Thanks

Ok, how do you know glute max is not firing? Can you do a deep squat and come up, can you run sprints? If yes, there is nothing wrong with your glutes maximus.

If there is any coordination issues or recruitment, these might help

1. Stretch your hip flexors before you do glute exercises or any leg exercises. Try the thomas test to see if you have tight hip flexors: http://www.youtube.com/watch?v=9PLXyShrNDc. Use tennis ball to do some rolling on ur glute med and hip flexors.
2. Isolate your glute max with exercise like supine bridge, clams, bird and dog, squeeze your glutes when walking , walking up stairs.
3. Integrate it with compound movements. Do more hip extension exercises, like single leg deadlift, deep squat and core stability work like planks and bridges. (not ab flexion)

And how you tried doing ass to the ground squats AND adding weights to it? You cannot just look and feel to see if it’s working. Do twice the weight you do on deep squats and tell me if you don’t still feel it.

Thanks -  and I also like your terms - “coordination issues or recruitment”. You nailed it. 
I can do single leg squats - 4-5 on right leg - 1-2 on left with much strain. Should I train my left side more? Due to injury my leg side (leg/glut) has weakness and my right side is very strong. I try to do single leg work and try to do more on left side - is this correct?

I can do single leg squats - 4-5 on right leg - 1-2 on left with much strain. Should I train my left side more? Due to injury my leg side (leg/glut) has weakness and my right side is very strong. I try to do single leg work and try to do more on left side - is this correct?

First check to see if you have similar ROM in both legs: mainly ankle & glutes. And when you do single leg squat, I am guessing, your left knee is collapsing in.

And where is the injury?

Yes do more single leg deadlift work but make sure you do those hip flexor stretches (one here: http://www.youtube.com/watch?v=qKFJOTk-cUE) before you do those and the do those glute isolation exercises. And some feel they can fire their glutes better if they on their their bare feet. Try it and see. Single leg squat is mostly glute medius. singe leg deadlift will get more of glute max.

And can you do a deep squat with your chest upright and no bending at the waist?