@heysamjg: Let’s get rid of that pain in the front of your thigh. For all the hamstring curls make sure you are contracting the muscle through the full range of motion. This can be tricky on some machines which is why I recommend the ball hamstring curls. As long as you keep your hips high, these will target the whole muscle. It’s normal when starting out with ball curls that your hamstrings feel like they’re going to snap. Stick with the exercise and the feeling will soon disappear as the hamstrings get stronger. You may want to perform them one legged to start with to see if there are any major imbalances between left and right leg. Move on to 2 legs when the imbalance had gone.