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Writer's picturePhysio Explored

29. Demystifying Core Muscles: Understanding Their Composition and Role in Injury Prevention

Core muscles have become a buzzword in fitness and wellness circles, often touted as the key to a robust and pain-free body. But what exactly are core muscles and are they as important as usually claimed? In this blog, we will delve into the intricacies of core muscles, debunk common myths, and explore their role in preventing injuries and pain, especially back pain.


Contrary to popular belief, the core is not just limited to the deep abdominal muscles. It encompasses a complex network of muscles that work together to provide stability, support, and power to the spine, pelvis, and hips.


The core is not just the set of muscles in front of your abdomen but includes and is synonymous with the trunk, the axial part of the body. Hence it has all the muscles axially from the shoulder to the button of your torso along with the pelvic and thoracic girdles. The core muscles include the rectus abdominis, transverse abdominis, internal and external obliques, erector spinae, multifidus, pelvic floor muscles, and diaphragm.


Among these core celebrities, one muscle often steals the limelight – the deep core muscle known as the transverse abdominis or TA.


The concept of "activating" the core has gained widespread attention, but it's important to note that the core muscles are constantly active to some degree. They provide a stable foundation for movement and posture throughout our daily activities. It also functions to control pressure in the abdominal cavity for vocalization, respiration, defecation, vomiting, coughing, etc. TA forms the posterior wall of the inguinal canal where its valve-like function prevents the viscera from popping out through the canal.


So, it's clear that TA's role goes beyond spinal support and pain prevention, raising intriguing questions about its involvement in other vital functions when it is said to be inactive, or, incorrectly activated, or, weak.


Surprisingly, there are multiple instances where the TA is damaged or put under abnormal mechanical stress, potentially affecting its activation and strength, without necessarily making the individual susceptible to lower back pain.


During pregnancy, the abdominal wall muscles undergo dramatic elongation, associated with force losses and the inability to stabilize the pelvis against resistance. Indeed, in a study of pregnant women, they were shown to have lost the ability to perform sit-ups due to this extensive elongation and subsequent force losses. Whereas all non-pregnant women could perform a sit-up, 16.6% of pregnant women could not perform a single sit-up. Astonishingly, there was no correlation between the sit-up performance and backache, i.e. the strength of abdominal muscle was unrelated to backache.


Often cited predisposing factors for LBP during pregnancy include body mass index, a history of hypermobility and amenorrhea, low socioeconomic class, the existence of previous LBP, posterior/fundal location of the placenta, and a significant correlation between fetal weight and LBP, rather than a localized musculoskeletal mechanical factor like spinal stability, emphasizing on a previously known fact that pain is a multifactorial condition

Pregnancy

Furthermore, postpartum, it would take the abdominal muscle about 4-6 weeks to reverse the length changes and for motor control to reorganize. For example, rectus abdominis takes about 4 weeks postpartum to re-shorten, and it takes about 8 weeks for pelvic stability to normalize. Yet, back and pelvic pain often decreases during this period, even when abdominal muscles are far from peak efficiency. This raises intriguing questions about the relationship between abdominal muscles and spinal stability.


In a study, the effects of a cognitive-behavioral approach were compared with standard physiotherapy on pelvic and lower back pain immediately after delivery. An interesting aspect of this research was that out of 869 pregnant women suffering from back pain during pregnancy, 635 were excluded because of their spontaneous unaided recovery within a week of delivery. This spontaneous recovery was during a period, well before the abdominal muscles had time to return to their pre-pregnancy length, strength, or control. Yet, this was a period when back pain was dramatically reduced.


Even in people suffering from obesity, like in pregnancy, the distension of the abdomen should disrupt the normal mechanics and control of the core muscles, leading to a host of muscles, but does everyone suffering from obesity have LBP?


A piece of common advice generally given is in the form of a core exercise where the patient is asked to contract the core actively (tucking the tummy in/bracing) anywhere from 20 to 100 times, throughout the day, and at worst, the patient is advised to tuck the tummy in constantly throughout the day which could stand as a hindrance to smooth recovery as people suffering from low back pain already report feeling stiff/tensed/rigid/locked/spasmed unconsciously as well as consciously as they become more careful of moving their bodies to prevent further pain and injury, tucking the tummy, even more, can potentially add to this feel of stiffness and lead to restricted movement and potential damage.


Moreover, increased intra-abdominal pressure as a result of tensing the abdominal muscles can exert potentially damaging forces on various pelvic ligaments.


Core muscles

In summary, while having a strong core has its place, it is not limited to just activation and strengthening of the TA. Also, it is essential to understand that core strength alone is not a panacea for preventing injuries and pain. The core muscles work in conjunction with each other as well as other muscle groups to maintain balance, alignment, and control during movements. It is time we recognize and accept that pain is personal, subjective, as well as, multifactorial experience being influenced by much more than solely a muscle.







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