Why is your head poking out like that? If you are like Justin Bieber and have a head that is poking all the way forward, you NEED to do this exercise. The DEEP NECK FLEXORS play a vital role in keep in the correct posture of your head. Here's how to strengthen them: Tuck your chin in. (Neck retraction) Nod your head downwards so that your chin pushes into your first. Hold for 30 seconds. Aim to feel a contraction at the front of your neck.