The leg press (leg press) is an excellent full-body exercise, activates each major muscle of the hip down. The sensation of pain in the muscles of the thigh and fatigue in the buttocks is normal and expected, but the pain in the knees is not. If your knees hurt when doing leg press, some of these situations are happening: you have a responsible pain injury, your technique is wrong or the leg press machine is not properly adjusted for your body.
If you have an injury it's time to visit a doctor. Problems with the technique and adjustment of the machine can be solved relatively easily. First, check your position on the machine again: your hips and back should rest on the seat. Adjust the platform and the position of your feet, so that when they are recharged on the platform with your knees bent 90 degrees, your big toes are still a little visible. Check that your feet and knees are pointing in the same direction. If the feet go to one side and the knees to the other, it is enough reason for there to be pain. Finally, do not immobilize your knees when the legs are fully stretched.