Resistance loop bands - Calories burned?

Hi Everyone!

Is there a way to at least estimate the calories burned while doing exercises with resistance band loops? I have a light, med, and heavy resistance band, but I can't seem to find any resistance exercises in the myfitnesspal database to be able to figure estimated calories burned. This morning I just logged my 15 min of exercises with my light resistance band as "mild stretching" which said I burned 39 calories....

Thanks for the help!