I haven’t noticed that much difference between men and women in regard to pelvic tilt but I would not be surprised if there is a significant difference. Most important here is to determine if the anterior tilt occurs during the pushoff. If yes then I say this is good because it indicates good technique. In essence the runner pushes the pelvis forward forcefully which indicates that the the forces are directed horizontally. When the hips get in front of the shoulders we see the anterior pelvic tilt. This typically occurs to runners who maintain good erect posture. If they have a forward lean it is difficult to produce this effect. It does not appear to be a strength issue; it is more of a technique issue. If there is a strength weakness it is low back strength.
in regard to leg stiffness I work on having the runners develop greater eccentric and isometric strength — mainly of the quads. it is the same for youngsters and adults.