worth a read

Cycles are very powerful. When you find a price series that has a controlling dominant cycle, all one needs to do to profit from it is execute a timing method on the price series change in line with the cycle. However cycles do have an powerful signal that is a little harder to market time.

http://www.safehaven.com/article/23005/cycles-produce-one-of-the-most-powerful-signals-part-one