Market rallies appropriately have been compared to the launch of a rocket. For a rocket to have enough momentum to exit the Earth’s atmosphere, the ship must be launched with enough initial force to overpower Earth’s gravity and penetrate the planet’s atmospheric constraints.
Market thrust theory portends the market has an atmosphere of boundaries as well, made up of old trading ranges, resistance lines and the tendency of investors to submit to the urge to pocket short-term profits.
If a market move is to have a chance of overcoming these boundaries, the initial rally must be propelled with a thrust adequate in force to send the market through levels of resistance that thwarted previous rally-launching attempts.
In thrust we trust
In his book "Winning on Wall Street," published in the mid-1980s, Martin Zweig detailed a particular breadth thrust signal that occurred on rare occasions where the sum of daily advancing issues over any 10-day period was twice the sum of declining issues on the New York Stock Exchange Composite Index. For an updated table, see "Traditional breadth thrust signals" (below).
After more than a decade (1992-2008) without a lot of guidance from traditional market breadth thrust indicators, such as Zweig’s 10-day, two-to-one NYSE Advance/Decline Ratio Signal, there were three sightings in 2009 that generated a renewed interest in understanding these signals’ historical significance.