Duplicate is frequently recorded but rarely changed. The purpose of Duplicate is to save the user time from entering information over again and it will carry forward until you change it.
For example, if ‘1’ associates with your athletes being present in the weight room and ‘2’ can associate with your athlete missing in the weight room. This is useful for attendance.
Carry Forward Shadow is a measurement that is taken from time to time but used often in calculating other values.
For example, if you measure body weight on Monday and want to use that measurement on Tuesday for one of your tests, the shadow feature will have the most recent measurement as the default.