Detect life of any type of price direction

If smoothed line of price have sharp decreasing direction at beginning of short time. So how to know how long it save this direction in future? What indicator support?

You can not know this for the future. You can only find out how log an average trend lasted in the past, by doing a trend length statistic with historical data.

Nobody know future but make best estimation about future. Actually you do not understand my major idea.