Better understand the importance of flexibility, stretching, and warming up before a workout with this exercise: Take a piece of cold/chilled play dough or modeling clay and try to make it stretch. Does it stretch very well? Hold the play dough or modeling clay with both hands. Is it warming up? What do you notice as it warms up? Once it is warm, try stretching it again. Does it stretch more easily now? How is the play dough like your muscles? Do you think it is important to warm up your muscles? Our muscles are much more flexible when they are warmed up before we use them.