Originally posted by: brikis98
First of all, soreness is not an indicator of anything. It is possible that your hamstrings just don't get sore easily, but are still being used plenty. On the other hand, if you don't feel yourself using them at all during squats and deadlifts, and you think they are still weak, then probably means your form is wrong. Without some videos to see, it's hard to guess exactly why, but here are some pointers:
Squat: you aren't using hip drive. Instead, you're probably doing a leg press like motion with a weight on your back, which is a very quad dominant and inefficient motion. If you have the SS book, re-read the squat chapter. If you don't have the book, get it! To have a strong squat, and to build the kind of strength that transfers well to the real world, you've got to engage our hamstrings, glutes and adductors in the motion.
This video shows some good cues for doing just that.
Deadlift: if you don't feel your hamstrings working like crazy on deadlifts, you're doing something very very wrong. Only thing I can guess is that you are yanking it up with your back, which is not only horribly inefficient, but also dangerous. Again, read the chapter on deadlifts in SS. The primary role of your back muscles in the lift is to keep your back rigid in full extension. The weight is lifted first by your quads (while the bar is below your knees) and then by driving your hips forward with your hamstrings and glutes (when the bar is above your knees). I suppose if you're doing the latter part using your back, then you won't feel it as much in your hamstrings, but it's impossible to tell without a video.