Determining the strength of a trend can be utilised with this simple function. More details of this indicator found here: http://www.currencysecrets.com/882/identifying-weakest-strongest-currencies-measuring-trend

trendStrength.mql4

double trendStrength( int b = 52, int per = 0, string sym = "" ) {
    if ( sym == "" ) { sym = Symbol(); }
    if ( b * 2 < iBars( sym, per ) ) { b = MathFloor( iBars( sym, per ) * 0.5 ); }
	double maDiff = iMA( sym, per, b, 0, MODE_SMA, PRICE_CLOSE, 0 ) - iMA( sym, per, b, 0, MODE_SMA, PRICE_CLOSE, b );
	double strVal = maDiff / iATR( sym, per, b, 0 );
	double result = strVal * MarketInfo( sym, MODE_TICKVALUE );
	return ( result );
}