Using IF, ISNUMBER and MAX function

Hi there,

I am using the following formula so that the excel sheet I am using for data entry will automatically select the highest of 3 values for each participant in a study I am conducting, so that the second sheet will contain the highest value for dynamic graphing.

=IF(ISNUMBER('Muscle data'!I2:I4), MAX('Muscle data'!I2:I4)," ")

Is there a way I can manipulate this formula so that I do not have to manually change the range from where I want the values to come from?

E.g. I2-I4, the next selection would be I5-I7 but I want the formula to change automatically. Is this possible?