So what exactly is “the core”? It is more than just a six-pack that many people envision. The core consists of the rectus abdominus, obliques, transverse abdominus, latissimus dorsi, hip flexors, diaphragm, pelvic floor, and the gluteal muscles.
Think of the body as a long connective chain with each muscle group representing a link in the chain. The core muscles are simply the middle links within the chain. The middle of the chain must be strong and stable during athletic movements.
The core muscles work to produce and transfer force from one part of the body to another during athletic movements. It also acts to stabilize the mid line of the body during movements that require a high degree of balance and body control. In regards to the “six pack” muscles (rectus abdominus); these muscles simply flex the torso in the sagital plane. However, the core muscles also extend, laterally flex, and rotate the torso during athletic movements in all three planes of motion.
The Core In Action
The core musculature plays an important role when trying to spike the ball over the net in volleyball. As a volleyball player approaches the net, she begins to lower her center of gravity by semi-squatting and then maximally jumping as high as possible. The lower body initiates the movement followed by rotation of the core and shoulder girdle. Energy is transferred along the kinetic chain from the lower body and core to the shoulder and arm. Once the core and shoulder muscles have maximally lengthened (rotated) then they contract to produce a smooth powerful strike at the ball. If the athlete is not able to transfer energy from the ground through the legs/hips, through the core, to the shoulder and out through the arm then ball will have considerably less velocity after she strikes the ball. It is extremely important that the athlete lengthen the muscles of the core (by rotating) and shoulder girdle so that those same muscles can forcefully contract to strike the ball with as much power as possible.
A baseball pitcher requires a large amount of core strength and stability to throw a pitch off the mound. The pitcher generates force by pushing up the mound with his legs and hips. This energy is then transferred through the core to the muscles of the shoulder girdle, then through the arm until the pitcher releases the ball. As a pitcher rotates his entire body around the core, these muscles are lengthening and then quickly contract to produce a smooth and powerful movement. In this example, the core is an important link between the lower body and upper body. If there are any weaknesses or energy leaks within the kinetic chain then the pitcher will not have the same velocity on the ball and may risk injuries. Many times the shoulder or arm is injured because the legs or core (links in the chain) are weak or do not function properly and cannot produce/transfer energy to the upper body. In this case, there is greater strain placed on the muscles/tendons/ligaments in the shoulder and arm to maintain velocity on the ball.