The core musculature is responsible for supporting the spine and trunk and translating the energy from the upper and lower extremities into efficient movement. Creating a strong core will allow you to keep optimal body alignment for all athletic activities. This is especially important for all athletes as creating a strong core, will reduce your fatigue and increase power. The most visible, and well appreciated of the core muscles is the Rectus Abdominis (RA), the muscle down the front of the abdomen, which gives you that ‘6 pack’ look. While the RA will allow you to flex your trunk (think sit-‐ups), it is probably the least important. Functionally, the muscles which stabilize and support your spine, the deep trunk muscles; Transversus Abdominis, Multifidus, Internal Oblique, External Oblique, Quadratus Lumborum, Iliopsoas, and Erector Spinae should be the focus of core training (Figure 1).
These deep muscles, although are not prominently visible but are responsible stabilizing the trunk, and transferring essential motion of the body. The trunk of the human body moves in three planes; sagittal (bending front and back), transverse (rotational), and frontal (side bending) (Figure 2). It is essential as trainers, to work the body in all three planes, and in both directions to ensure balance for proper functioning of the musculoskeletal system. Strengthening the core in all three planes will also decrease injury by preventing excessive force on all structures of the kinetic chain. Many of the exercises we do using Lagree Fitness work the body in these 3 planes, and it is important to know which plane you are working in (Figure 2).
When we work the body in the positive direction of the sagittal plane, the main muscle working is our Rectus Abdominis, RA (the six-pack muscle). The RA is responsible for trunk flexion so it’s the antagonist to the Erector Spinae, which bends the spine backwards. The giant crunch, super crunch, megaformer crunch and tailbone angel crunches work the RA and give you that awesome 6-pack. The Iliopsoas, also assists with motion in this plane flexing the hips. Serve the stabilizing the spine in the negative sagittal plane. Motion in the transverse plane or the rotational plane is when the body twists from the hips and shoulders; think swinging a baseball bat or turning around to look over your shoulder while you're changing lanes on the freeway. Transverse plane exercises are performed by a variety of muscles, but the primary muscle is the External Obliques. Kneeling torso twists (Figure 3) are the classic exercise, working the oblique muscles in the transverse plane (Figure 3).
The External Obliques turn the body in the opposite direction that they contract (figure ). Thus if you want to train the right external oblique muscles, you need to do torso twists in a counterclockwise direction (toward the left). You will also be working the left internal oblique muscles, and all of the muscles that are mermaid twists, soul train, single arm rows, and angel torso twists. Movement in the frontal (or side-bending) plane, occurs when one bends laterally away from the midline of your body. Mermaid Crunch (Figure 4) is the prototype exercise that works the body in the frontal plane.
Other exercises that work the muscles in the frontal plane, include side plank, scrambled eggs. The Obliques, Quadratus Lumborum, Multifidus, and Erector Spinae are the main muscles the body uses for side bending. While it looks good to have a nice six pack, it is important to train all the core muscles to ensure creating strength in all three planes, and in both the negative and positive direction to maintain a balanced body, and remain pain and injury free. When choosing exercises for a specific routine, keep in mind that different fitness, and sculpt the torso evenly.