Size does matter. There is just no way a one hundred pound woman is going to outlast a hundred and fifty pound man. Men are genetically going to be stronger in most instances. Most women get used to being on the bottom when rolling with male partners. In an attack on the street it’s likely an assailant is going to pull/push the woman down on the ground. There are a multitude of attacks from the bottom. I read a really impressive article by Krista Scott Dixon “tips for female grapplers.” You can find this article on www.grapplearts.com. I want to mention a couple of things that she addresses. First learn and understand the angles. Downward pressure is less effective than pressure that is directed diagonally into the opponent and through the mat say in a forty five degree angle. Movement, especially hip movement is critical. Never and I mean never just lay there flat waiting for the opponent to mount you. Always keep moving, Keep them moving as opposed to trying to move them. Don’t let them settle in and drop their weight. This will make it harder for you to escape. Dixon says “gain position by erosion.” Popcorn to a better position getting it inch by precious inch. Keep them unbalanced never letting them establish a firm foundation. Learn to frame and frame and frame. Avoid trying to wonder woman them off of you by pushing with all your might. This will just tire you out. So bridge and shrimp, bridge and shrimp, bridge and shrimp while keeping the frame. If you want to read the article click on the link above and search for tips for the female grappler. Check out her thoughts on playing close verses open guard when rolling with the big fellas.