How do I adjust the walking belt if it slows when I walk on it?

First, remove the key and unplug the power cord. If the belt is overtightened, use the hex key to turn both idler roller screws counterclockwise 1/4 turn. When properly tightened, you should be able to lift each edge of the walking belt 5 to 7 cm off the platform. Be careful to keep the belt centered. Then plug in the power cord, insert the key, and walk for a few minutes, repeating until properly adjusted.