Core (anatomy)

Last updated November 04, 2023

The core or trunk is the axial (central) part of an organism's body. In common parlance, the term is broadly considered to be synonymous with the torso, but academically it also includes the head and neck. Functional movements are highly dependent on this part of the body, and lack of core muscular development can result in a predisposition to injury.^[1] The major muscles of the core reside in the area of the belly and the mid and lower back (not the shoulders), and peripherally include^{[ clarification needed ]} the hips, the shoulders and the neck.

Muscles

Major muscles included are the pelvic floor muscles, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm. The lumbar muscles, quadratus Lumborum (deep portion), deep rotators, as well as cervical muscles, rectus capitus anterior and lateralis, longus coli may also be considered members of the core group.^[2]

Minor core muscles include the latissimus dorsi, gluteus maximus, and trapezius.

Functions of the core

The core is used to stabilize the thorax and the pelvis during dynamic movement and it also provides internal pressure to expel substances (vomit, feces, carbon-laden air, etc.).

Continence

Continence is the ability to withhold bowel movements, and urinary stress incontinence (the lack of bladder control due to pelvic floor dysfunction) can result from weak core musculature.

Pregnancy

Core muscles, specifically the transversus abdominis, are used during labor and delivery.

Valsalva maneuver

Core muscles are also involved in the Valsalva maneuver, where the thorax tightens while the breath is held to assist, often involuntarily, in activities such as lifting, pushing, excretion and birthing.

Anatomical posture and support

The core is traditionally assumed to originate most full-body functional movement, including most sports. In addition, the core determines to a large part a person's posture. In all, the human anatomy is built to take force upon the bones and direct autonomic force, through various joints, in the desired direction. The core muscles align the spine, ribs, and pelvis of a person to resist a specific force, whether static or dynamic. ^[3]

Static core function

Static core functionality is the ability of one's core to align the skeleton to resist a force that does not change.

Example of static core function

From Army FM 3-22.9 page 4-16 ArmyProne.jpg — From Army FM 3-22.9 page 4-16

An example of static core function is firing a rifle in the prone position. To maintain accuracy, the shooter must be able to transfer their body weight and the weight of the rifle into the earth. Any attempt of the shooter to create a dynamic motion of the sights (muscle the sights onto the target vs. allowing the posture to aim) will result in a jerky posture where the sights do not sit still on the target. For the shooter to maintain accuracy, the muscles cannot exert force on the rifle, and the skeleton must be aligned to set the rifle (and therefore the sights) onto the target. The core, while resting on the ground and relatively far away from the rifle, is nevertheless aligning the spine and pelvis to which the shoulder and arms and neck are connected. For these peripheral elements to remain static, and not move unnecessarily, the spine, pelvis, and rib cage must be aligned towards this end. Thus the core muscles provide support of the axial skeleton (skull, spine, and tailbone) in an alignment where the upper body can provide a steady, solid base for the rifle to remain motionless.

Resistance: Gravity
Plane of movement: Coronal (side to side), Sagittal (forward and behind the anatomical position).

Dynamic core function

The nature of dynamic movement must take into account our skeletal structure (as a lever) in addition to the force of external resistance, and consequently incorporates a vastly different complex of muscles and joints versus a static position.

Because of this functional design, during dynamic movement there is more dependence on core musculature than just skeletal rigidity as in a static situation. This is because the purpose of the movement is not to resist a static, unchanging resistance, but to resist a force that changes its plane of motion. By incorporating movement, the bones of the body must absorb the resistance in a fluid manner, and thus tendons, ligaments, muscles, and innervation take on different responsibilities. These responsibilities include postural reactions to changes in speed (quickness of a contraction), motion (reaction time of a contraction), and power (amount of resistance resisted in a period of time).

Example of dynamic core function

An example of this is walking on a slope. The body must resist gravity while moving in a direction, and balancing itself on uneven ground. This forces the body to align the bones in a way that balances the body while at the same time achieving momentum through pushing against the ground in the opposite direction of the desired movement. Initially, it may seem that the legs are the prime movers of this action, but without balance, the legs will only cause the person to fall over. Therefore, the prime mover of walking is achieving core stability, and then the legs move this stable core by using the leg muscles.

Related Research Articles

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The human leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.

The push-up is a common calisthenics exercise beginning from the prone position. By raising and lowering the body using the arms, push-ups exercise the pectoral muscles, triceps, and anterior deltoids, with ancillary benefits to the rest of the deltoids, serratus anterior, coracobrachialis and the midsection as a whole. Push-ups are a basic exercise used in civilian athletic training or physical education and commonly in military physical training. They are also a common form of punishment used in the military, school sport, and some martial arts disciplines. Variations of push-ups, such as wide-arm push-ups, diamond push-ups target specific muscle groups and provide further challenges.

Abdominal muscles cover the anterior and lateral abdominal region and meet at the anterior midline. These muscles of the anterolateral abdominal wall can be divided into four groups: the external obliques, the internal obliques, the transversus abdominis, and the rectus abdominis.

The rectus abdominis muscle, also known as the "abdominal muscle" or simply the "abs", is a pair of segmented skeletal muscle on the ventral aspect of a person's abdomen. The paired muscles are separated at the midline by a band of dense connective tissue called the linea alba, and the connective tissue defining each lateral margin of the rectus abdominus is the linea semilunaris. The muscle extends from the pubic symphysis, pubic crest and pubic tubercle inferiorly, to the xiphoid process and costal cartilages of the 5th–7th ribs superiorly.

An exercise ball is a ball constructed of soft elastic, typically in 5 diameters of 10 cm increments, from 35 to 85 cm, and filled with air. The air pressure is changed by removing a valve stem and either filling with air or letting the ball deflate. It is most often used in physical therapy, athletic training and exercise. It can also be used for weight training.

The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral abdominal wall, deep to the internal oblique muscle. It is thought by most fitness instructors to be a significant component of the core.

The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax.

Abdominal exercises are a type of strength exercise that affect the abdominal muscles. Human abdominal consist of four muscles which are the rectus abdomens, internal oblique, external oblique, and transversus abdominis. When performing abdominal exercises it is important to understand the effects, functions, the types of exercises, and think about how to perform this exercise safely.

A bent-over row is a weight training exercise that targets a variety of back muscles. Which ones are targeted varies on form. The bent over row is often used for both bodybuilding and powerlifting.

The crest of the ilium is the superior border of the wing of ilium and the superiolateral margin of the greater pelvis.

Diastasis recti, or rectus abdominis diastasis, is defined as a gap of about 2.7 cm or greater between the two sides of the rectus abdominis muscle. The distance between the right and left rectus abdominis muscles is created by the stretching of the linea alba, a connective collagen sheath created by the aponeurosis insertions of the transverse abdominis, internal oblique, and external oblique. This condition has no associated morbidity or mortality. Physical therapy is often required to repair this separation and surgery is an option for more severe cases. Standard exercise rarely results in complete healing of the separated muscles.

Active sitting is the practice of enabling or encouraging individuals to engage in physical activity while seated. It is also commonly known as dynamic sitting. The underlying notion highlights the advantages of incorporating flexibility and movement while sitting, as it can positively impact the human body and allow the completion of certain tasks that require sitting. "Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated." One of the earliest forms of active sitting is the common rocking chair which allows forward and backward swaying motion.

Standing, also referred to as orthostasis, is a position in which the body is held in an erect ("orthostatic") position and supported only by the feet. Although seemingly static, the body rocks slightly back and forth from the ankle in the sagittal plane. The sagittal plane bisects the body into right and left sides. The sway of quiet standing is often likened to the motion of an inverted pendulum.

The Roman chair is a piece of exercise equipment. It is mainly used for the lower back, but can also target the buttocks, hamstrings, and abdomen. The definition of the equipment, and what 'Roman chair exercise' specifically means, is not clear.

In kinesiology, core stability is a person's ability to stabilize their core. Stability, in this context, should be considered as an ability to control the position and movement of the core. Thus, if a person has greater core stability, they have a greater level of control over the position and movement of this area of their body. The body's core is frequently involved in aiding other movements of the body, such as running; thus it is known that improving core stability also improves a person's ability to perform these other movements.

<span class="mw-page-title-main">Leg raise</span> Strength training exercise

The leg raise is a strength training exercise which targets the iliopsoas. Because the abdominal muscles are used isometrically to stabilize the body during the motion, leg raises are also often used to strengthen the rectus abdominis muscle and the internal and external oblique muscles.

The hip bone is a large flat bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts: the ilium, ischium, and the pubis.

<span class="mw-page-title-main">Pelvis</span> Lower part of the trunk of the human body between the abdomen and the thighs

The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.

A kick is a skill in association football in which a player strikes the ball with their foot. Association football, more commonly referred to as football and also known as soccer, is a sport played world-wide, with up to 265 million people around the world participating on a yearly basis. Kicking is one of the most difficult skills to acquire in football. This skill is also vitally important, as kicking is the way in which passes are made and the primary means by which goals are scored.

Core Strength Vinyasa Yoga is a style of yoga as exercise created by American yogini Sadie Nardini in 2006. Central to this style is a movement referred to as a 'wave' (softening). The structure of this practice includes a 7-step framework which is applied to each pose within a sequence. Nardini incorporates aspects of Kundalini Yoga, Sivananda Yoga, Anusara Yoga, Iyengar Yoga, and portions of movement sequences from Ashtanga Vinyasa Yoga. Maintaining an internal focus on joy in the moment is part of the practice philosophy. This style integrates postures with learnings from many disciplines including physics, biology, and geometry, influenced by the works of Leslie Kaminoff. It incorporates traditional yoga philosophy from the Yoga Sutras of Patanjali. It emphasizes muscles that are deep within the body and includes the use of 'waves' in order to enter and exit poses. Examples include physical moves that activate muscles close to the spine—such as psoas and quadratus lumborum in order to build support for the body from within before generating outward expression of that movement. The purpose of deep core focused poses in this practice is to improve and deepen breathing. This perspective differs from other styles in which the purpose of deep core work is to stabilize the back. In this practice, keeping belly soft and core strong improve breathing. "Belly Bonfire" breath is one example of a deep core breath technique that involves focus and target of attention and breath with softer abs. Pelvis is viewed as the body's physical center of gravity in this system.

References

↑ Karageanes, Steven J. (2004). Principles of manual sports medicine. Lippincott Williams & Wilkins. pp. 510–511. ISBN 978-0-7817-4189-7 . Retrieved 26 March 2011.
↑ Kisner, Carol; Colby, Lynn Allen (2007). Therapeutic Exercise. F A Davis Company. ISBN 9780803615847.
↑ Guide to building a strong core