When teaching my first graders I typically jog at the front of the pack for our warm up lap, stopping at any point a student passes me. Towards the end of the lap I tell the students that I am going to turn on my jets and then I sprint to the end leaving them in the dust. After doing this one day a child towards the back looked up at my assisstant and sadly told her "I forgot to bring my jets today, but tomorrow I'm gonna bring them"