With an influx of thugs seemingly deciding to make random attacks a regular occurrence there are a rash of martial arts classes being taught. Some offer great instruction at reasonable prices and if you follow their martial arts techniques closely, you will be in a much better position to defend yourself. The problem is that with so many classes and teachers there are bound to be some con artists who don't know what it is they're doing. They make all sorts of claims, stating that they are a ‘Grandmaster' and that everything they teach you is guaranteed to work. This would be all fine and good only for the fact that their super secret techniques are more likely to hurt you than your opponent.
Amongst these idiotic martial arts techniques is the blocking of a strike from an extremely hard object like an iron bar using your forearms. You don't need to be an expert in the fields of biology and physics to know that blocking an object that is far harder than your arms and traveling at a fearsome velocity is not going to end well for you. The real outcome will see your arms broken, leaving you as an easy target for the attacker. The smart option in this instance is to move away from the object before taking the opportunity to catch them off balance and deliver some damage of your own.
If this doesn't strike you as dangerous enough, how about trying to kick a knife out of an attacker's hand? If you are trying to learn martial arts and have a teacher that gets their students to do this then walk right out the door. First of all, the kick will have to be incredibly accurate as you are aiming for a very specific target. Secondly, the knife would need to be held quite loosely and you better believe that a thug with a knife will be clinging onto it for all that he's worth! Finally, you are more likely to miss and get cut.