what is the polarity principle 
the polarity principle refers to the price phenomenon whereby once resistance is broken it becomes support and vice versa a break of a resistance zone will usually see a quick test of the breakout level to see if the break holds or if it fails and reverses lower the bottom linea resistance point or zone develops when prices are unable to move higher from that zone resistance levels can be found on short term or long term charts with long term resistance levels carrying more weight for the overall direction of the next move in the security resistance levels are identified by technical analysis or visual inspection using such tools as trendlines horizontal lines moving averages and bollinger bands from a trading perspective resistance levels offer various trading opportunities you may go with the flow and buy into a resistance zone looking for a break higher you might jump in on the long side after a breakout has occurred or you could look to sell into the resistance zone going short holding the view that the resistance will hold and prices will turn lower no matter your situation once prices near a resistance zone it s time to take notice of the price action and subsequent opportunities 