The Concepts of Core Stabilization
The core can be defined as the lumbo-pelvic-hip complex: there are 29 muscles that have attachments within this area. The importance of the core is to maintain the optimal length tension relationship between the functional agonists and antagonists. The achievement of optimal muscular relationship’s result in the optimum force couple relationships in the lumbo-pelvic-hip complex. Clark cites the following studies by Sahrmann (1997), Strohl et al, (1981) and Warmerdam (1996) as they suggest that maintaining optimum length tension relationship and force couple relationships allows for the maintenance of optimum joint athrokinematics in the lumbo-pelvic-hip complex during functional kinetic chain movements. The achievement of this allows for correct neuromuscular control of the entire kinetic chain and allows the muscles to contract with the correct balance of eccentric (braking), concentric (accelerating) and isometric (dynamic stabilization) contractions during functional movements throughout all planes of motion. Myers in his book Anatomy trains (2001) shows in detail the routes of the pathways of the myofascial meridians and how these are all routed through the core musculature of the body and this shows us how important it is that the musculature of the core is trained correctly to provide optimal movement within the whole body. The above has been concluded by Clark (2002) as “the core operates as an integrated functional unit, enabling the entire kinetic chain to work synergistically to produce force, reduce force and dynamically stabilize against abnormal force.” It can be concluded that the core or lumbo-pelvic-hip complex must be trained in such a manner that allows the core to efficiently distribute the balance of weight, absorb the forces and transfer the ground reaction forces. The integrated interdependent system of the lumbo-pelvic-hip complex therefore needs to be trained in a fashion that allows for it to function efficiently during dynamic activities.
The problem area that may have to be addressed more than gaining functional strength, power, endurance and neuromuscular control of specific muscles that enable them to carryout functional movements is the ability to develop the muscles to maintain spinal stabilization. For it is the effective stabilization of the spine musculature that will allow it to fully develop the strength, power, neuromuscular control and muscular endurance of its prime movers. Research by Hodge’s et al, (1996) state “A weak core is a fundamental problem inherent to inefficient movement that lead to predictable patterns of injury.” The role of that the core musculature plays is to provide a protective mechanism for the spine and helps to protect it from unwanted forces that are part of functional movements. It is therefore imperative that we as fitness professionals design programmes that help our clients to develop strength, neuromuscular control, and power and muscle endurance of the core/lumbo-pelvic-hip complex. The effective design will allow us to help our clients to develop greater balance and muscular functioning of their entire kinetic chain. The development of the greater levels of neuromuscular control and stabilization strength helps to provide an improved biomechanical position of the kinetic chain and therefore will allow for the efficient movement throughout the entire kinetic chain.
The development of neuromuscular efficiency is achieved by ensuring good postural control and stability strength are executed, as this will allow the body to decelerate forces of gravity, ground reaction forces and momentum. The importance of the neuromuscular efficiency is such that poor levels of neuromuscular efficiency will limit the ability of the kinetic chain to maintain optimum levels of forces resulting in loss of dynamic stabilization. This decease in stabilization may lead to compensation factors such as synergistic dominance, reciprocal inhibition and arthrokinetic inhibition as well as poor posture during movement. This will lead to extra strain and stresses being placed upon contractile and non-contractile tissue. Which in turn will progress to the start of the pain/injury cycle, as the muscles will develop repetitive micro trauma, abnormal biomechanics and injury?
The Lumbo-Pelvic-Hip Complex Musculature
The key musculature of the lumbar spine includes the transversospinalis group, erector spinae, quadratus lumborum and latissimus dorsi. The key abdominal musculature includes the rectus abdominus, external oblique, internal oblique and transverse abdominus. The key hip musculature includes the gluteus maximus, gluteus medius and the psoas. Once again it is important to remember that the musculature operates in functional integrated units and the central nervous system is designed to optimise the selection of muscle synergies, not isolated muscles.
The key therefore to proper function of the core is down to the correct levels of synergistic interdependent functioning of the whole lumbo-pelvic-hip complex as this enhances the stability and neuromuscular control throughout the entire kinetic chain.
The aim of core stabilisation is to maintain good posture (dynamic postural control) throughout functional movements and this helps to prevent the onset of serial distortion patterns. The aim is therefore to provide exercise that will address any postural misalignment in order that correct muscle tension relationships and arthrokinematics are maintained during movement. Gambetta (2006) states:
“Posture is clearly an integral part of many aspects of movement. In fact, I believe that dynamic postural alignment and subsequent dynamic muscle balance are fundamental movement skills. So it should be no surprise that a training regime for good posture is very similar to any functional strength conditioning program. We need to train strength, flexibility, balance and movement. We need to incorporate multi-joint and multi-plane work with high proprioceptive demand. We need to target deficiencies with remedial work whenever warranted.”
Gambetta (2004) further states the importance of the anti-gravity muscles (gastroc/soleus group, quadriceps group, glutes and erector spinae group) as “the larger core muscles known as anti-gravity muscles play a major role in maintaining a sound, functional athletic posture.” In other words there should be an understanding on the muscles that defy gravity and keep us in a balanced position. To further our knowledge of the anti-gravity muscles we should also develop a better understanding on the role gravity plays on loading the body. Gambetta (2004) suggests:
“Gravity and its effects must be a prime consideration when designing and implementing a functional core training programme or we are not preparing the body for the forces that it must overcome. Therefore we must be aware of our orientation to gravity when we are training the core. When we are standing, we are parallel to gravity and when lying or seated we are perpendicular to gravity. The demands of individual sports will dictate the primary body position we should use to train the core. For most sport, the majority of core training should be performed in upright and moving positions.”
The use of exercises to strengthen and stabilise the core can help to improve the optimum neuromuscular efficiency by improving the dynamic postural control. Research by Beckmann and Buchannan (1995), Bullock-Saxton (1994, 1993) have shown that clients who have low back pain have an abnormal neuromotor response of the trunk stabilisers accompanying limb movement, it has also been noted that there is an increase in the postural sway and an decreased amount of the limits of stability. To further worsen the situation numerous research studies have shown that if clients have had lower body ligamentous injuries they will have decreased dynamic posture stability in the proximal stabilisers of the lumbo-pelvic-hip complex. These ligamentous injuries can lead to further problems with a decrease in the muscle activity. Ligamentous and joint injuries may further lead to muscle inhibition. The muscular inhibition has the effect of altering neuromuscular control of other muscular segments and the kinetic chain then becomes secondary to proprioception and kinaesthesia. In conclusion this means that all of the muscles that cross over the injured or painful swollen area are inhibited in carrying out their full function.
The final neuromuscular consideration that must be addressed is that of athrogenic muscle inhibition. This comes about as a direct result of poor arthrokinetic reflexes that are mediated by joint receptor activity. Therefore clients who show poor arthrokinematics will result in the muscles that move the joint being inhibited. Clark (2002) gives an example of this as “If an individual has a sacral torsion, the Multifidus and gluteus medius can be inhibited. This leads to abnormal movement in the kinetic chain. The tensor fascia latae become synergistically dominant and become the primary frontal plane stabiliser. This often leads to tightness in the iliotibial band, which decreases frontal and transverse plane control at the knee. Furthermore if the Multifidus is inhibited, the erector spinae and psoas become facilitated. This will further inhibit the inner unit stabilisation mechanism (internal oblique and transverse abdominus) and the gluteus maximus, which also decrease frontal and transverse plane stability at the knee.” The question is how do we help to prevent the above postural neuromuscular problems? The answer is to include core stabilisation exercises that will improve the strength, dynamic stability, power and muscular endurance of the lumbo-pelvic-hip complex whilst helping to prevent injury and its chain reactions that are started after an injury occurs.
- Michael Clark; Essentials of Integrated Training Part 5: Core Stabilization Training; http://www.Ptonthenet.com
- Thomas W Myers, Anatomy Trains; Churchill Livingstone: 2001
- Hodges PW, Richardson CA: Inefficient Muscular Stabilization of the Lumbar Spine Associated with Low Back Pain. Spine 21(22):2640-2650, 1996.
- Gambetta: Perfect Posture: http://www.momentummedia.com/articles/tc/tc1602/posture.htm
- Gambetta: Middle In Motion: http://www.momentummedia.com/articles/tc/tc1407/middlemotion.htm
- Beckman SM, Buchanan TS: Ankle Inversion and Hypermobility: Effect on Hip and Ankle Muscle Electromyography Onset Latency. Arch Phys Med Rehabil 76(12):1138-1143, 1995.
- Bullock-Saxton JE: Local Sensation Changes and Altered Hip Muscle Function Following Severe Ankle Sprain. Physical Therapy 74(1):17-23, 1994.
- Bullock-Saxton JE, Janda V, Bullock M: Reflex Activation of Gluteal Muscles in Walking; an Approach to Restoration of Muscle Function for Patients with Low Back Pain. Spine 18(6):704-708, 1993.