My friend, this "default" that we all fall back upon is the ROOT OF THE PROBLEM!
Unless u r willing to unlearn bad postural and movement patterns and habits, u will continue to activate some muscles while neglecting others, just because u feel more comfortable. The price to pay for not identifying yr faults and changing will b far higher than to take that effort to see what feels 'natural' yet is in reality harming u daily.
Take the common sidelying straight leg raise exercise, meant to activate the gluteus medius, as an example. The correct way to execute the exercise is to point the toes of the exercising leg down towards the ground as u lift the leg up and then lower it. If u let the toes point straight ahead or even diagonally outwards, u activate some other muscles in yr hip as well, including the TFL and quadriceps.
Ask yourself this question: Why do so many do this exercise and yet do not get well?
Is it not because when they get on with their every day living, they assume that since they have done the work, the glute med ought to activate by itself? Yet this does not happen, as evidenced by the past 28 pages of testimonies. Why is this so, since this is the muscle that so many experts point out as key to this coordination problem?
This is because we do not walk and run daily with our feet/knees positioned in the manner that they r when we were doing glute med exercises!
We don't do that because it doesn't 'feel natural', because it violates what is our 'default' gait and movement habits!
Just try it out for yourself and u will see that as u change the way yr feet r positioned, yr entire body up north will also need to re-adjust itself. U will realise that ytr shoulders r rounded, neck craned, back rounded, butt 'swayed back', knees too straight and locked, and all these will make a standing position with feet pointed forward or slightly inwards feel very unnatural!
In order to accomodate this new feet position, one which activates yr glute med, u will need to undo all that poor posture up north! U will b surprised at how much better u will feel, and u will breathe better. U will run better too!