Intensity is the amount of physical power (expressed as a percentage of the maximal oxygen consumption) that the body uses when performing an activity.
I will do yoga 4 times a week and stretches everyday for 2 months to improve my flexibility. I will do these flexibility movements every single day to get more blood flow into my body and improve my flexibility. I will know that my goals have been met when I don't feel pain or strain when I do yoga or stretch my body.