Charlie Hoolihan discusses core training and the complexity of the human body. He defines the core muscles as those between the sternum and knees, including the abdominals, low back, and hips. Core training aims to enhance force transfer between upper and lower extremities through movement-specific training. Hoolihan recommends exercises like planks, bird dogs, resistance band exercises, stability ball exercises, medicine ball exercises, and TRX/suspension training to develop a strong, balanced core while emphasizing proper form and fluid movement. Resources for further information are provided.