Everytime I do good mornings or squats (with feet flat) I am always uncertain as to whether or not my lower back is perfectly arched or not. I find it to be perhaps the most difficult thing to check in such an exercise especially since I don’t have a mirror or a qualified trainer available at all to check my form while doing the exercise with as focus as I can put into the exercise.
Also, I obviously can’t just turn my head around to see if my lower back is set up correctly. It’s frustrates me because I am so concerned about doing a given exercise with perfection and yet I don’t how I am supposed to know by myself with 100% certainty as to whether or not my back is perfectly arched?