Walking for about five minutes before you start running loosens your muscles, increases blood flow, and gently raises your body temperature to prepare you for the dynamic warm up to come. It is especially important if you head out the door first thing in the morning or after you’ve sat at a desk for most of the day.
Don't worry about any particular pace. Just walk how you feel.
Butt kicks actively stretch your quads and send a message that it’s time for them to come online; you’re going for a run, and you need them to join.
Start by standing tall, relaxing your shoulders, and holding your arms loosely at your sides as you would while running. Now, begin to jog, but with an exaggerated back kick … so exaggerated that you kick your butt. Perform about 15 to 20 on each side, preferably on flat ground.
For a more advanced version: Increase your cadence.