Low Back Pain and Exercise Strategy, Pt. I
Unfortunately, low back pain (LBP) is an issue that many people suffer from on a regular basis; 60-80% of adults in Western countries are expected to experience LBP during their life (Gordon and Bloxham, 2016). LBP can be mild or very debilitating, and can stem from a variety of causes, and thus can be difficult to diagnose and treat. Acute LBP is defined as back pain lasting less than 6 weeks, while chronic low back pain (CLBP) persists for longer than 3 months (Gordon & Bloxham, 2016). Patients with acute LBP are at a 40% elevated risk of developing CLBP, which underscores the need for timely intervention (Gordon & Bloxham, 2016).
Long periods of inactivity have been shown to adversely affect recovery from CLBP (Gordon & Bloxham, 2016). Exercise is thus an important tool that can be used to treat CLBP and improve daily movement functions, but should be used with caution. Many cases of LBP are considered “non-specific” meaning a direct mechanism of pain is unknown (Auregard & Carroll, 2019). In such cases, general exercise programs including components of strengthening, flexibility, and aerobic exercise are recommended (Gordon & Bloxham, 2016); however a thorough screening process should be performed to diagnose postures and loads that may cause pain or discomfort. In cases in which an injury mechanism is known, care should be taken not to replicate such movements during exercise. In cases of non-specific acute LBP, it is suggested that some forms of exercise may aggravate the acute injury, and that patients with non-specific acute LBP typically recover within 4-6 weeks with or without treatment (Gordon & Bloxham, 2016). However, exercise has been shown to positively affect recovery from CLBP, indicating that a targeted approach may be beneficial for treating or preventing ongoing back pain (Gordon & Bloxham, 2016).
One method of exercise which has been shown to be beneficial for improving CLBP is core strength training (Chang et al., 2015; Wang et al., 2012). The core muscles, referring to the deep and shallow muscles which compose the trunk, are the primary muscles responsible for maintaining spinal stability during loaded movement (Chang et al., 2015). When a person is required to lift a load, the core muscles can be activated to various degrees to induce a stiffening effect which “braces” the spine and locks it into a neutral position -- referring to the maintenance of the spine’s correct natural curvature within an acceptable range.
The human spine can be described as a flexible rod, enabling movement in a wide range of motion including rotation, flexion (forward bending), and extension (arching). Whether or not spinal movements are a mechanism for injury or cause of LBP remains a debated topic. It is impossible to avoid spinal flexion and other movements during daily living, and the spine and the soft tissue structures supporting it are capable of adaptation. However, repeated flexion-extensions cycles under low loads of spinal compression have been shown to have a deleterious effect on the intervertebral disc structures (Callaghan & McGill, 2001). Additionally, high rates of compressive load applied to spines in end ranges of flexion has been observed to promote the damage and mechanical failure of lumbar discs using in vitro models as well as videofluoroscopy of a powerlifter attempting a maximal deadlift (Wade et al., 2014; Cholewicki & McGill, 1992). While it is certainly also possible to injure the spine under high loads in neutral postures (Veres et al., 2010), it is my impression that the general encouragement of a neutral posture, particularly under load, proposes the lowest potential risk for injury. Additionally, the maintenance of a neutral spine position often promotes the most mechanically efficient method of movement, as stability in the trunk provides a firm foundation for the expression of power through more mobile joints such as the hip and shoulder (McGill et al., 2009).
For these reasons, training the core muscles’ strength and endurance often represents an effective targeted approach to relieving CLBP and reducing the potential of future injuries. At Human Project Training, we employ a variety of core stability exercises which train both the strength and endurance of the trunk musculature. In part two of this series we will cover the proper execution and rationale behind several of these exercises.
References
Augeard, N., & Carroll, S. P. (2019). Core stability and low-back pain: a causal fallacy. Journal of exercise rehabilitation, 15(3), 493–495. https://doi.org/10.12965/jer.1938198.099
Callaghan, J. P., & McGill, S. M. (2001). Intervertebral disc herniation: Studies on a porcine model exposed to highly repetitive flexion/extension motion with Compressive Force. Clinical Biomechanics, 16(1), 28–37. https://doi.org/10.1016/s0268-0033(00)00063-2
Chang, W. D., Lin, H. Y., & Lai, P. T. (2015). Core strength training for patients with chronic low back pain. Journal of physical therapy science, 27(3), 619–622. https://doi.org/10.1589/jpts.27.619
Cholewicki, J., & McGill, S. M. (1992). Lumbar posterior ligament involvement during extremely heavy lifts estimated from fluoroscopic measurements. Journal of Biomechanics, 25(1), 17–28. https://doi.org/10.1016/0021-9290(92)90242-s
Gordon, R., & Bloxham, S. (2016). A Systematic Review of the Effects of Exercise and Physical Activity on Non-Specific Chronic Low Back Pain. Healthcare (Basel, Switzerland), 4(2), 22. https://doi.org/10.3390/healthcare4020022
McGill, S. M., McDermott, A., & Fenwick, C. M. J. (2009). Comparison of different strongman events: Trunk muscle activation and lumbar spine motion, load, and stiffness. Journal of Strength and Conditioning Research, 23(4), 1148–1161. https://doi.org/10.1519/jsc.0b013e318198f8f7
Veres, S. P., Robertson, P. A., & Broom, N. D. (2010). ISSLS prize winner: How loading rate influences disc failure mechanics. Spine, 35(21), 1897–1908. https://doi.org/10.1097/brs.0b013e3181d9b69e
Wade, K. R., Robertson, P. A., Thambyah, A., & Broom, N. D. (2014). How healthy discs herniate. Spine, 39(13), 1018–1028. https://doi.org/10.1097/brs.0000000000000262
Wang, X. Q., Zheng, J. J., Yu, Z. W., Bi, X., Lou, S. J., Liu, J., Cai, B., Hua, Y. H., Wu, M., Wei, M. L., Shen, H. M., Chen, Y., Pan, Y. J., Xu, G. H., & Chen, P. J. (2012). A meta-analysis of core stability exercise versus general exercise for chronic low back pain. PloS one, 7(12), e52082. https://doi.org/10.1371/journal.pone.0052082