The forthcoming document is going to examine the term ‘core stability’ and review the most effective strategies publicised for trunk conditioning within the world of Sports Performance. There have been many articles written on the topic, both science based research and anecdotal theories, however the confusion on what ‘core stability’ is and how its best conditioned for Sports Performance still leave many coaches searching for answers.
Firstly ‘Core Stability’ and ‘Core Strength’ are commonly used in the same breath, many have debated them since the 1980’s. This is especially apparent within the field of fitness professionals when trying to promote core stability in sports conditioning programs. The clarification between the two has to be determined and is fundamentally important when training outcomes become paramount.
The term ‘core’ is often used to best describe the lumbopelvic region of the body. Panjabi (1992) gave the classification of ‘core stability’ a definition that suggested, “The capacity of the stabilizing system to maintain the intervertebral neutral zones within physiological limits.” It is then important to know the stabilizing system is split up in to 3 regions: The passive subsystem, the activation muscle subsystem, and finally the neural subsystem (Leetun, 2004). Bergmark (1989) gave a division of the active muscle subsystem, categorizing them as ‘global and ‘local’ groups. This classification was based on their primary roles in stabilizing the core. The global group consisted of the large superficial muscles such as the rectus abdominis, internal obliques, transverse abdominis, erector spinae and lateral portion of the quadratus lumborum. This group is geared towards the transfer of force between the thoracic cage and pelvis. They act to create intra abdominal pressure. Conversely, the local group classifications were those that consisted of the small, deeper muscles. Their roles control intersegmental motion between adjacent vertebrae. For example: multifidus, rotators, interspinal and inter transverse muscles. The core muscles are said to be like guy wires, with tension being monitored by the neural subsystem. This subsystem has the compelled task of analyzing movement in relation to forces and providing feedback to the global and local subsystems to enhance the stability required to hold the body.
On the other hand ‘core strength’, often confused with core stability, must be understood and differentiated. Greenwood (2007) provided a clear definition as to the difference between core stability and strength. The definition however was best applied to the rehabilitation sector, suggesting core stability refers to the ability to stabilize the spine as a result of muscle activity, with core strength referring to the ability of the musculature to then produce force through contractile forces and intra-abdominal pressure. Akuthota (2007) defined core strength as muscular control of force required around the lumbar spine to maintain functional stability. This statement opposes that of Lehman (2006) who defined the traditional concept of strength as; the maximal force that can be generated at a specific velocity by a muscle or muscle group. The confusion between what to train and how is largely proportionate to the different demands needed by the body in different sporting activities. That of an athlete compared to that of the general population will dictate the level of complexity of the chosen core exercises. The exercises for a field sport athlete, who will need multi directional dynamic movements will require added resistance in comparison to a general population person with a lower back problem, the requirements may be more static with less resistance required and a higher time under tension.
The anatomy of what is considered the ‘core’ is varied between that of the rehabilitation sector and that of the athletic sector. The core from a rehabilitation viewpoint has been described as a box or a double winded cylinder, with the abdominals as the front, paraspinals and glutes behind. The diaphragm is the top or roof and the hip girdle as the base. Although, in the athletic field, the core is seen as all of the anatomy between the sternum and the knees with a close look at the abdominals, lower back and hips. The data even stretches to the shoulder and pelvis regions in some of the research, as the transfer of force is greatly considered in many sporting movement patterns. Leetun (2004) suggested that hip muscle activation significantly influences the ability to generate force in the upper leg muscles and it has been identified that the hip muscle activation is important when looking at core stability and trying to improve core strength. Wilson (2005) considered the Gluteus Maximus to have an essential role in core stability and hip control. It is this cross data that often leaves fitness professionals confused on what is the correct methods to apply when trying to achieve core stability outcomes, especially when looking at the sporting population, as the majority of core stability research has been done on the rehabilitation scope of practice.
When training for core stability we must consider the process we select. Training programs must include all the processes that involve muscular strengthening and motor control of the musculature that involves the core. Many rehabilitation programs include stability exercises, although plenty of scientific articles show little evidence of their efficiency to enhance performance. Data does show however, that an enhancement on neuromuscular control can be increased using numerous variations of these methods. Joint stability, contraction, balance, proprioceptive, plyometric and sport specific exercises are believed to help, with proprioceptive shown to be most valuable in the physiotherapy world. It would then be common to see equipment such as wobble boards, Swiss balls and discs being used. Motor control stability, core strength training and systematic strength training are sub areas that Comerford (2008) identified when training the core for stability and strength. He suggested performing high and low threshold training and argued that it is essential for local muscles to be targeted and for low threshold training to be performed to avoid any imbalances, which may lead to movement dysfunctions and injuries. It is suggested this method is best used to teach the muscles how to work in isolation before moving on to more advanced functional positions and patterns.
In conclusion, the amount of research collected and the amount of data that point in favor of specific core stability or core strength exercises for activating muscle is limited. The problems that have arisen are conflictions between a wide variety of data, and a broad spectrum of studies. Ways of collecting methods, the type of exercise techniques used and the subjects being tested for analyzing have left us with the conclusion that there isn’t a one single exercise that fine tunes the core, activates it, nor challenges all of the core muscles and their subsystems. This has been discussed in previous paragraphs. Therefore, we take away that it is a combination of exercise requirements needed over a time frame that will elicit the response and outcomes needed for core stability and strength, relative to the individual. There has to be future research that identifies and clarifies specificity towards which of the exercises that are most effective in resulting in beneficial outcomes, dependent on performance and goal, as well as time frame best to be used, be that for an athlete or the general population. The studies that are currently out there are informative but fail to clarify elements such as periodization and or there correlation to the level of athlete being tested.
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Leetun, D. (2004). Core Stability Measures As Risk Factors For Lower Extremity Injury In Athletes (Vol. 6). Med Sci Sports Exerc.
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