Body grips refers to having a robust grip of the upper torso largely focused on having strength in the intercostal muscles.
What is body grip? Consider the expression “Get a grip on yourself”. What does this mean? One interpretation is that if refers to having a good grip on our body through the chest or upper abdomen. The concept of body grip is best understood by imagining that you are going to lift a heavy weight. Before you start, you prepare yourself by stretching your chest taut to expand the chest open and extend the pelvis rearward. While imagining lifting the weight you extend the large muscles attached to the front and back of the ribcage, which do most of the lifting, and you also extend the smaller muscles that hold the ribs together to help provide a firm foundation. These small muscles are the intercostals and they provide the essence of the body grip because they hold together the actual bones of the ribcage and make it a single solid stucture.