The long-term market trend changes only occasionally its direction (in most indices only 4 times during the last 20 years). Therefore, you can assume that most of the times the trend will continue in the same direction as is.

When the trend is “Up”, you can expect that the market most likely will continue to go up. When the trend is “Down”, you can expect that the market most likely will continue to go down.

Thus when the trend turns “Up” or is “Up” for a certain market, as a Trend Investor, you want to own index funds or low-cost mutual funds that follow that market index. When the trend turns or is “Down”, you want to be out of these funds.