I have a history of pulling my thigh muscle from sprinting. I was an athlete growing up and right now I'm making a football comeback at a little bit older age. I used to pull everything in my upper leg here and there but mainly my groin and thigh muscle (it feels like my vastus intermedius to be exact). I've tried warming up really good, stretching, not stretching and a few other things. The other day I had a very good warmup (but didnt stretch) then after my 2nd or 3rd full speed sprint it felt like my thigh muscle was pulled. Except for the other day I've noticed that I do better with not pulling things when I dont stretch.

This pulled thigh muscle goes back to my little leauge football days is it possible I have some deformity or injury I dont know about. I never had problems with my legs while lifting or competing in any sports only in a full sprint. A chiropractor I know who played D1 ball and trains athletes on the side thought I might need to strengthen my leg muscles more. Which growing up or a few years back would make sense because I was very fast and had a great vertical even though I didnt train my legs that much. But I would think now that my legs would be stronger. Any tips or help I cant be pulling muscles if I'm going to make a football comeback? Maybe have an MRI done or anything else? Thanks