Ladies the best defense is, if you can, get someone to accompany you. A 120 pound women will have absolutely no chance against a 200 pound man. The muscles and bone structure of most men is made to take punishment. And if the dude is crazy and fit you will have no chance. The only thing I can see that can actually work is the headbutt, if you're lucky. Keep your keys between your finger and your biggest key as if you're holding a knife. Punch, gouge, scream, kick and never give up. They don't mention it in the video but to use those techniques you must be highly trained to be effective.