If you want to identify big moves within a 1 minute bar you need to go down to the tick level. While tick charts aren't available in MT4, the fact that the start function executes every tick means that you can quite easily write some code to check the range of the market in a shorter period ( X seconds, say). This is another way to identify sharp moves and avoid trades based on them. It's very simple to determine the range of the last X seconds:
Backtesting this would be subject to significant errors due to the way the software simulates ticks based on the 1 minute bars.