When I was in my forties and was squating fairly heavy, 495lbs for 2 sets of 10 reps, it would seem that every 6 to 8 months I would get pain in my tensor fasciae latae to the point I had to back off the weight for a few weeks. The gym had an adduction machine and an abduction machine that I had never bothered using.
I decided that maybe if I could strengthen my TFL’s I might avoid the pain I would get. So at the end of my thigh routine I decided to train my TFL muscles. I used the adduction machine to stretch my groin to increase my range of motion on the abduction machine. I had worked up to using the entire weight stack from an extremely wide stretch. After 3 sets of 8 reps on the adduction machine I would switch to the abduction machine where I used much lighter weight doing 3 sets of 8 reps, where I held the flexed position for about 3 seconds. I figured the TFL was a stabilizing muscle and thought holding the flexed position might be the best strategy.
Once I started training on the adduction and abduction machines, I never again experienced TFL pain doing squats.