Adding trendline for certain values

[Texasandreas]

Working on a training tracker where I input what amount of lifting that has been done. Using this data I convert the data using a formula to get a calculated 1RM which is a calculated max lift. For instance lifting a weight of 100 pounds 10 times would give a 1rm of 133.
I would like to use a diagram to visualize this and also like to add a trendline giving a rate of development. Updating it on a weekly basis and see how the line changes. The problem is that as the future workout cells contains this function and also that the workout number is prestate.This will result in zero values on the y axis making the trendline negative. Tried adding a function that gives the cell "" value if no data is inserted the the workout cell but this does not help. Did the same for the workout number index but this also resulted in same way.

I added the spreadsheet. The cells highlighted in darker grey are the ones were I want to base values for the calculation. The diagram is based on the row below.

[etaf]

replace the "" with #N/A
that should stop the chart plotting a line of zeros
or any other value that you do not want to plot
that way you can setup the chart for future values that will not then drop to zero or change the trendline

http://easy-excel.com/excel-line-cha...w-to-avoid-it/