Glute Ham Raise Progression

So, I've decided that SLS alone is not giving my hamstrings enough focus and have started to add GHR to my Killroy-format workout. And it looks like I need to go back to the most basic progressions of this exercise, specifically, holding a glute-ham "bridge". I lie on my back with my knees bent at about 45 degrees, heels and knees together. Using glute and ham strength, I push my hip into the air and hold for 30s at the top...do this 3 times.

When I hold at the top, I feel a very intense stretch...almost painful after long duration....on the inside of both kneecaps. Is this normal? Is there a stretch I should be doing to help loosen this? Part of the reason I'm doing the exercise is because I tore my ACL and mensicus in my left knee 6 years ago. I'm fully rehabbed and feel very strong on it. However, playing soccer a few weekends ago, I felt a very mild strain in my LCL (I think ?) when my ankle and foot were abducted and I was bearing weight on my left knee.

I have full ROM now and am just wanting to strenghten the surrounding muscles to make sure there's enough support, and that inner knee sensation I get at the top of the GHR feels pretty intense.

Thanks!

JM

Tight quads?

I have often used glute ham bridge curls in lieu of floor glute ham work for beginners. Use a furniture slider or frisbee on carpet. Slide legs in and out or do just on one leg.

Wow. REALLY tight inner quad muscle at knee. I need to add that to my stretching routine. Thanks for simpler GHR progressions, too.