Invert direction reverses your acceleration graph and flips it horizontally.
The Motion Analysis tool uses global acceleration as a default setting, which takes an athlete’s acceleration with respect to the pool. The Triton unit automatically detects the direction the athlete is moving in, providing acceleration from one end of the pool to the other.
However, during turns, the athlete is moving in 2 different directions (towards the wall, and then away from the wall), and so the system has to select one as the most predominant direction. There is also a slim possibility that the system makes an error in judging the direction the athlete is travelling in. When this happens, the acceleration graph will display the opposite trend for this lap. Instead of seeing a positive spike for positive acceleration, for instance, you will see a negative trend on the graph.
Turning on invert direction corrects this, giving you acceleration in the opposite direction.
The image below demonstrates how when a swimmer turns, negative acceleration is now in the direction they are swimming.
To turn on invert direction