I first learned this technique from Claude Pauch in Virginia. He has a range of hip hop lessons where he also teaches the body roll and how to stall when doing a helicopter move.
A chest pop is a basic move using rib isolation (isolating the pectoral muscles in your chest). The biggest problem most beginner hip hop artists/dancers have with chest pops is rolling the shoulders or doing chest "expansions" (this is when the artist or dancer inhales air to expand their chest or use their back bone to push their chest out.) This improper technique of the chest pop can cause back pain. This is where having hip hop lessons with an instructor can be helpful in the beginning stages of learning the fundamental hip hop moves, such as the Stomp in krumping (and don't think there is only one style of stomp in krumping).
To perform the chest pop you first need to isolate your pectoral muscles (the muscles in your chest). A helpful hint is to breathe out as you engage your pectoral muscles. This will help not only to relax the muscles but also to gain better control to provide a more fluid and convincing "pop" of the chest. Now you just need to pop your chest out and then drop it back. Remember not to roll your shoulders as this is not how the technique is performed. Practice this over and over again until you have it down pat, a good idea is to do it in front of a mirror or supervised as it is hard to tell when performing the move if you are rolling your shoulders slightly as you pop your chest.
Now if you want to take the next step in the hip hop lessons you can use your fingers and hand to further emphasis the chest pop. This can be done by pulsating the fingers.To do this place your hand on your chest about where your heart is and hold the fingers out slightly bent like you are holding a small 5cm ball over your heart. As you pop your chest expand the fingers like you are trying to reach around a 30cm basketball. This adds character to the chest pop move and can add a more dramatic chest pop.
This chest isolation is like an explosion it connects the moves in hip hop. It is commonly used when transferring the energy of a move from your feet up to your chest. which results in a "bang" when the chest pops out.
An example would be to use a stomp and a chest isolation move together. As you stomp the ground the energy transfers up your leg through to your stomach, continues up into your chest giving you an adrenaline pump, as it continues onto an arm swing. The chest isolation pop is most commonly used in the krumping style of hip hop as it is a highly explosive style of dance.
In today's hip hop lesson you have learned about the chest pop which is a rib isolation exercise designed to link moves coming from the feet up through the body to the arm's
For my next article I will be talking about another move taught by Josh Jackson again which is the body roll. The body roll is learning to combine all your body's motions into one. With the body role you will need to focus on the details of running up from the legs and through the hips, up the chest and finishing through the fingers.