The common myth about quicksand is that it sucks you down. It you struggle then you will sink because your body movements actually dig deeper into the muck. Quicksand is highly saturated sand or silt or mud where water has not evaporated or leached out. If sand or dirt particles won't sink then neither will you so long as you stay calm and allow yourself to float to the top. If it is very muddy then when you struggle you may create a suction in the mix that has to be broken before you can come out. If your leg is stuck because of suction, you need to take something (walking stick, branch, piece of hose) and push it down along your leg to break the suction. A piece of hose is ideal because it lets air in around your trapped leg to break the suction. Best rule: don't go hiking alone.