# Spark Lines in the Fit Log

Sometimes it's useful to get a graphical indication of how a particular MotionMetriq has changed over the course of a fit, such as after you've completed a [sustainability test](/section-04-aero/sustainability-test.md).

Velogic Studio makes that easy through the use of a feature called "Spark Lines". To see a spark line, just click "SHOW GRID" to open the fit log grid, and then click on one or more body metrics.

You will see a series of lines displayed overtop of the fit log grid:

![Fit log grid displaying spark lines visualization with colored trend lines for selected metrics](/files/2jqxFJrU0zh0q8b0X8zi)

If a metric has left/right values, you will see a solid line for the left metric and a dotted line for the right.

You can click on multiple metrics and the lines will be automatically assigned different colors.

Simply click on the same metric again to turn the spark line off for that metric.


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