With market players questioning when the stockmarket rally will run out of steam - or if it already has - equity strategists at Morgan Stanley have produced some timely research.

Teun Draaisma and the European equity strategy team at the investment bank have been poring over 19 major secular bear markets, including the US in the 1930s, the US and Europe in the 1970s, Gold in the 1980s and Japan in the 1990s.

They have found some interesting patterns - summarised in a nice chart - and used them to assess the potential course the current market will take. 

Looking at the 19 examples, they summarise:

"Each involved a peak-to-trough decline of at least 40% lasting at least a year. The median of these bear markets showed a 57% decline over 30 months."

"The usual rebound rally is 71% over 17 months... Structural bear markets are always followed by a strong rebound, typically from the moment authorities take decisive action."

"A turn in the rate cycle is often the trigger for the next correction. Often the peak in the rebound rally has been around, or prior to, a change in the interest rate cycle."

"Broad multi-year trading ranges followed the initial rebound in 10 of 19 bear markets. In most cases, structural problems in the real economy acted as a headwind to a new bull market, such as financial bubbles, high debt levels, fiscal deficits, current account deficits, deflation and high inflation."

Applying their conclusions to the latest European bear market between June 2007 and March 2009, they point out it was very typical: a 57% decline over 21 months.

Turning to the rebound rally, Morgan Stanley's strategists note that Europe is now up 42% from its trough, in 5 months "so if it ends here, it would have been a very small rebound rally."

The conclusion is:

"If the aftermath of these 19 secular bear markets is anything to go by, the current rally could go on a bit longer; is likely to stall a few months before the first Fed rate hike, which we expect in Q3 of 2010 ... and is likely to be followed by some sort of trading range for years to come because of the structural problems of financial sector and household deleveraging as well as the poor state of government finances."