I die a little inside every time I hear someone mention “the core.” It has become a term that is used so often that people forget to think about what it actually means and if it even makes sense. A weak or unstable core has been added to the ever-growing list of things we think can cause pain, along with tight fascia, trigger points, muscle imbalances, poor posture, immobile livers, and altered pelvic alignments, to name a few. Is there any reason to believe that core strength is such a problem for so many people we see? Why are pelvic tilts, planks, and other stability drills the universal prescription for patients with back pain? Do athletes really need to do core exercises to perform better? As one would expect, the current body of research casts some doubt on long-held assumptions in the physical therapy world.
The Traditional, But Potentially Antiquated View
If you are reading this, you probably have a good idea of what someone means when they say core strength or core stability, although a precise definition is hard to come by. We have all had the lecture detailing the musculature between the chest and the hips, the lab where we pretend to try and contract the transversus abdominis (TrA) instead of the rectus abdominis, and the patient we had to instruct on how to perform a plank or a pelvic tilt with a march. Core strength or stability can be roughly defined as the ability of the central muscles (whichever ones you want to include) to contract and transmit forces. Core strength or stability exercises are any exercises performed to improve strength, endurance, or control of these muscles.
The traditional view of the relationship between core stability, core strength, and back pain has been outlined already here, here, and here. In brief, research from Paul Hodges et.al. showed that the TrA of people with back pain had a delay in firing, as compared to people without back pain, when they were asked to perform a movement task. As Eyal Lederman points out, Hodges’ work confirmed a broader idea that was already well established; motor control strategies and muscle activation patterns change when there is pain, and the back was no different. Both Lederman and Lehman mention that despite the humble results of this study, it has been misinterpreted and its importance magnified, to the point we are at today. The supposed importance of TrA is ubiquitous, and I would bet any therapist reading this learned how to assess it and prescribe exercises for it. And, as we all learned, the TrA is but one of many “core” muscles that we think need to be trained. It is thought that the TrA, in conjunction with the lumbar multifidi (LM), rectus abdominis, and the obliques and maybe your glutes and pecs too, help prevent your delicate spine from disintegrating. However, the misinterpretation of Hodges’ work and the cascade of research that followed it may be because of a simple logical fallacy: assuming causation from correlation.
Correlation and Causation
Changes in core muscle activation, morphometry, and histology are associated with patients with back pain (Wong, 2013). Which causes which? Should we even assume one causes the other? The mirror image of what has been proposed could be true: perhaps back pain causes the changes we see in core musculature. There are a few interesting studies that attempted to clarify this relationship.
- Wong et.al. attempted to determine if baseline characteristics of the TrA and multifidus, including activation, morphometry, and histology could predict clinical outcomes for patients with back pain. They found that the current evidence is largely conflicting, and there are no papers that displayed a strong predictive value of these factors (Wong, 2013).
- Wong et.al. attempted to determine if changes in TrA and LM characteristics were associated with changes in LBP and LBP-related disability. They found no or limited correlation between positive clinical outcomes and changes in the following variables: TrA or LM thickness, anticipatory muscle activation, TrA lateral slide, LM endurance. Meaning, the people that got better after an episode of back pain did not have corresponding positive changes in characteristics of their core muscles. (Wong, 2014).
- Hodges et.al. performed an interesting experiment with a unique design to assess the causal relationship between pain and altered motor control. They assessed the timing of core musculature onset during upper extremity tasks in multiple conditions; with or without pain elicited via saline injections. The researchers found that recruitment patterns were in fact altered by pain, with delays in TrA firing being the most consistent. (Hodges, 2003).
- Steiger et.al. performed a systematic review looking at the association between positive clinical outcomes and various aspects of performance for patients with chronic non-specific low back pain. From 16 studies, the authors found there were no correlations between changes in mobility, trunk extensor strength, trunk flexor strength, and back muscle endurance (Steiger, 2011).
“Based on the findings of our review and on similar information from other systematic reviews and studies, we suggest that changes in physical function are largely unable to explain changes in the clinical condition in cLBP patients, and that the important ‘‘side effects’’ of exercise therapy (including, amongst other things, changes in psychological variables such as fear-avoidance beliefs, catastrophizing and self-efficacy regarding pain-control) should be more specifically emphasised and investigated in future rehabilitation programs” (Steiger, 2011).
The above papers cast some doubt on the traditional view of the core and back pain; particularly that altered core performance may not be the cause of back pain, and the relationship may be a bit more complicated than we thought. We can no longer assume that the people that get better with traditional spinal stability exercises do so because of changes in core muscle function.
Do Core Exercises Even Work?
Undoubtedly, clinicians will tell you that they have seen success utilizing core exercises, and there may therefore be something of clinical interest happening, even if it isn’t correcting abdominal muscle “dysfunction.” So what does the literature say in regards to the efficacy and effectiveness of core exercises for patients with back pain? Are they better than regular exercise? Let’s start with some clinical trials. In particular, I will be focusing on larger scale, higher quality trials that compare traditional core exercises, i.e. TrA activation or LM activation, as compared to general trunk exercise, general strengthening, or aerobic exercise. They should use pain or function as an outcome measure.
- Koumantakis et.al. compared specific stabilization and general endurance exercises to general endurance exercise alone for 55 patients with recurrent low back pain, measuring paraspinal muscle strength and fatigue, repeated trunk flexion, repeated sit to stands and the fifty foot walk test. The found that though both groups improved, there were no significant differences between groups on the outcome measures used (Koumantakis, 2005).
- Cairns et.al. compared conventional physical therapy versus conventional physical therapy plus traditional core stabilization exercises for 97 patients with recurrent, non-specific low back pain and found that both groups performed about the same on the all outcome measures utilized at all time periods. The authors suggest that this may be due to an inability to appropriately classify patients into etiology-based categories, and those that truly benefit from stability exercises were not isolated. (Cairns, 2006)
- Ferreira et.al. compared general exercise, motor control exercise for trunk musculature, and spinal manipulative therapy for 240 patients with chronic low back pain and found that after eight weeks of treatment, all groups improved, but the motor control group did a bit better in the beginning (Ferreira, 2007).
- Franca et.al. compared typical TrA and LM exercises to superficial abdominal strengthening exercises for 30 patients with chronic low back pain and found that after 12 sessions of exercises, both groups improved on pain scores and on the Oswestry back questionnaire. The TrA/LM group scored significantly better on these measures than the superficial group, but the clinical importance of this difference was not assessed and the authors ultimately suggest both protocols can work (Franca 2010).
- George et.al. compared four different conditions for the prevention of low back pain in patients in the military. 4,325 soldiers were divided into four groups: a core exercise group, a core exercises plus psychosocial education session, a traditional lumbar spine exercise group, and a traditional lumbar spine exercise group plus psychosocial education session. They found there that type of exercise made no difference in the prevention of new episodes of back pain, but the presence of a psychosocial education session reduced incidence by a small amount. (George, 2011).
- Kachanathu et.al. compared core stabilization exercises to traditional physical therapy strengthening exercises for 30 bowlers with chronic low back and measured pain via the VAS and disability via the oswestry questionnaire. They found that both groups improved significantly after eight weeks, but the group performing core stabilization exercises had statistically better results. However, the differences in improvement were small and of debatable clinical importance (Kachanathu, 2012).
- Shnayderman etl.al. compared a general strengthening exercise program to a walking program for 52 patients with chronic low back pain and found that after six weeks, both groups had improved scores on the six minute walk test, functional disability scales, and trunk muscle endurance tests. There were no significant differences between groups on any outcome measures (Shnayderman, 2012).
- Vasseljen et.al. compared core stability exercise, sling exercise, and general exercise for 109 patients with chronic low back pain and found that after eight weekly sessions, there were no changes in onset of deep abdominal muscles after a rapid shoulder flexion movement. (Vasseljen, 2012).
- Sung et.al. compared core stabilization exercises to spinal flexibility exercises for 46 patients with recurrent low back pain and found that disability decreased in the core stabilization group but not the flexibility group, and there were no changes in core muscle fatigability in either group after four weeks (Sung, 2012).
- Puntunmetakul et.al. compared core stabilization exercises to stretching and hot packs for 42 patients with clinically diagnosed instability and measured pain, disability and abdominal muscle activation ratios. They found the core stabilization group did significantly better on all outcomes (Puntunmetakul, 2013).
- Javadian et.al. compared general exercise to general exercise plus core stabilization exercises for 30 patients with chronic low back pain secondary to spinal instability and measured the translation and rotation of lumbar segments via xray during movement. They found that both groups had positive changes in lumbar segment movement, but the core stabilization group did statistically better, on the order of a few millimeters/degrees. (Javadian, 2015).
- Palekar et.al. compared core exercises to superficial strengthening exercises for 52 patients with low back pain and found after six weeks, both groups improved in pain scores and disability, but the core stabilization group improved on TrA activation (Palekar, 2015).
- Shamsi et.al. compared core stabilization exercises to general trunk strengthening exercise for 43 patients with chronic low back pain and measured their performance on the trunk flexor, trunk extensor, and side bridge endurance tests, as well as disability and pain. After 16 sessions, both groups improved and neither group did better than the other (Shamsi, 2016).
- Ahktar et.al. compared core stabilization exercises to general strengthening and stretching exercises for 120 patients with chronic low back pain and found that both groups saw a reduction of 3.08 points and 1.71 points, respectively, on the VAS after 6 weeks (Ahktar, 2017).
- Bhadauria et.al. compared core stabilization exercises, dynamic strengthening and pilates for 44 patients with low back pain and found that after 10 sessions, each group improved on each outcome measure. However, the core stabilization group did the best (Bhadauria, 2017).
- Selkow et.al. compared core stabilization exercises to inactive control for 42 patients with or without low back pain and measured TrA activation (measured via the ratio of thickness of the TrA during contracted and relaxed states) and timing after four weeks. They found that those in the exercise group improved in both measures as compared to the controls, who had no change. However, the amount of improvement on timing was small, about .2 seconds (Selkow, 2017).
There is a huge number of trials looking at the effects of core stabilization exercises and comparing them to other standard treatments, including, but not limited to superficial trunk strengthening, aerobic exercise, general exercise and other passive modalities. The general trend was that most of the time, most groups improved regardless of what type of exercise they did, but sometimes the groups performing core stabilization exercises did better in the short term. These differences however, were generally small, did not last, and were of debatable clinical importance. Next, we will take a broader look at core exercise literature with some systematic reviews and meta-analyses.
Systematic Reviews And Meta-Analyses
- A review and analysis of 12 trials revealed that specific stabilization exercises were helpful for patients with spinal or pelvic pain, and is better than inactive interventions, but not more than spinal manipulative therapy or traditional physical therapy programs. In addition, stabilization exercises were not found to be effective for patients with acute back pain (Ferriera, 2006).
- A review of 18 trials revealed similar results to the 2006 study above; specific stabilization exercise can be helpful for patients with non-acute back pain and is better than inactive interventions, but not much different from other active interventions (May, 2008).
- A review and analysis of 14 trials, five of which compared motor control exercise to other exercise therapy found that both types were essentially the same and neither was better for reducing pain or disability (Macedo, 2009).
- A review and analysis of five trials for patients with chronic low back pain revealed that core stabilization exercises were better than general exercise for improving pain and disability in the short term, but there were no differences in the medium and long term (Wang, 2012).
- A review of 15 trials revealed both motor control exercises (i.e. exercises designed to target motor function of specific muscles like TrA and LM) and general exercises can help patients with subacute or acute back pain, and neither was consistently better than the other (Brumitt, 2013)
- A review and analysis of 16 trials found that motor control exercises were superior to general exercises in the short, intermediate, and long term for decreasing disability (Bystrom, 2013).
- An update of the review by May performed in 2008 was done and included 29 studies. The researchers found the additional studies added to the May study reinforced the original conclusion; stabilization exercises can help alleviate low back pain symptoms by small amounts, but not better than other active approaches at any time frame.
“This review cannot recommend stabilisation exercises for low back pain in preference to other forms of general exercise, and further research is unlikely to considerably alter this conclusion.” “The rehabilitation strategy surrounding stabilisation exercises has been challenged and has been suggested could encourage unhealthy thoughts and beliefs on pain and movement” (Smith, 2014).
- A robust Cochrane review and analysis of 29 trials found that motor control exercises can help for patients with chronic non-specific back pain more than no intervention, and may be slightly more effective than exercise in the short and intermediate term. However, there is little or no difference between a motor control approach and other types of exercise.
“Given the minimal evidence that MCE is superior to other forms of exercise, the choice of exercise for chronic LBP should probably depend on patient or therapist preferences, therapist training, costs and safety” (Saragiotto, 2016).
- A review and analysis of 11 studies revealed that stabilization exercises were better than general exercises in the short term (Gomes, 2016).
In the majority of robust reviews and analyses, core stabilization exercises were equally effective or better than general exercises in the short term, but in the long term, there were typically no differences between the two approaches. Next, we will take a look at some of the research focusing on athletic populations. Do they really need to do core exercises?
Do They Matter For Athletes?
Every athlete has probably performed some core exercise in their training. In my one-season run as a fifth-string 100M sprinter during my last year of high school, I certainly performed a few planks in between my runs. It makes some sense; many sporting activities rely on the transfer of power from the upper body to the lower body, or vice-versa. Wouldn’t you want a strong core for that? Can core exercise actually improve performance?
- A review of 24 studies looking at the relationship between core exercise and performance as measured in many different ways, showed generally mixed results, without any strong links. Many of the studies did report improvements in measures of core strength but not necessarily performance. The heterogeneity in the types of core exercises performed, the way performance is measured, and the demands of each sport make any links hard to see. In addition, core exercises are not performed in isolation, making it difficulty to attribute improvements to core exercises alone (Reed, 2012).
- A review looking at the relationship between core exercises and low back pain in athletes found that the five studies they were able to include were not of sufficient quality to make any firm conclusions. Most of the studies reported benefits for athletes performing core exercises, but the quality and risk of bias made the results questionable (Stuber, 2014).
- A review and analysis of 15 correlation studies and 16 intervention studies revealed that there were small correlations between trunk muscle strength and athletic performance and core strength training only had small effects on proxies of physical performance. The studies assessed were of limited quality, but the authors concluded that overall, core strengthening exercises probably have little effect on performance (Prieske, 2015).
- In a narrative review on the relationship between core strength and athletic performance, the authors reported exercises for core strength have not been tested for effectiveness for athletes, there is insufficient evidence to suggest that athletes have core strength deficits, EMG recordings of trunk muscle activation patterns varied significantly, and traditional strength training exercises are sufficient stimuli for the preferred adaptations (Wirth, 2016).
The reviews thus far have cast some doubts on the importance of core exercises in an athlete’s program, and questions how much core strength or stability is even related to performance. I suspect that classical strength training should be sufficient to build load tolerance and general “robustness,” and any sports specific skills that seem to require core strength can be improved by practicing the task itself, instead of a core exercise.
Meaningful, Challenging, And Fun
This brings us back to the original question: Do core exercises matter?
Not as much as we thought…and maybe not at all.
For patients with back pain, there is no doubt utilizing the traditional core exercises can help reduce pain and improve function by small amounts. We have good reason to believe however, that something else is going on besides an improvement in stability or core muscle function that correlates with a resolution of symptoms. As mentioned by Steiger, perhaps the real improvement comes from the “side effects” associated with core exercise, like changes in beliefs about back pain, locus of control, fear avoidance, and pain catastrophizing.
Luckily, these side effects are probably not unique to the core exercise approach and may be found with any exercise that the patient likes to do, is empowering, and makes them feel good. Core exercises are just a very good option that makes sense to people. There is good reason to believe that a general exercise approach can be just as effective, especially as time goes on. No matter what approach we chose for our patients, it is important to address any maladaptive beliefs they have regarding their back pain and make sure they understand that they are not weak.
If you choose to incorporate a core exercise approach, you need to make sure you are not contributing to those beliefs by suggesting they have a weak core or their spines are fragile, or they need more stability. Any exercises that are meaningful, fun, and challenging, could confer benefits to patients in pain. While core exercises may check off those boxes, they are not the only ones that can. For patients with back pain, you first need to explain the complex relationship between core strength, back pain, and exercise. Then, simply give them options, let them lead on their treatment of choice, and guide them down the path they want to take.
- Akhtar, M. W., Karimi, H., & Gillani, S. A. (2017, 08). Effectiveness of core stabilization exercises and routine exercise therapy in management of pain in chronic nonspecific low back pain: A randomized controlled clinical trial. Pakistan Journal of Medical Sciences, 33(4). doi:10.12669/pjms.334.12664
- Bhadauria, E. A., & Gurudut, P. (2017, 08). Comparative effectiveness of lumbar stabilization, dynamic strengthening, and Pilates on chronic low back pain: Randomized clinical trial. Journal of Exercise Rehabilitation, 13(4), 477-485. doi:10.12965/jer.1734972.486
- Brumitt, J., Matheson, J. W., & Meira, E. P. (2013, 09). Core Stabilization Exercise Prescription, Part 2. Sports Health: A Multidisciplinary Approach, 5(6), 510-513. doi:10.1177/1941738113502634
- Byström, M. G., Rasmussen-Barr, E., & Grooten, W. J. (2013, 03). Motor Control Exercises Reduces Pain and Disability in Chronic and Recurrent Low Back Pain. Spine, 38(6). doi:10.1097/brs.0b013e31828435fb
- Cairns, M. C., Foster, N. E., & Wright, C. (2006, 09). Randomized Controlled Trial of Specific Spinal Stabilization Exercises and Conventional Physiotherapy for Recurrent Low Back Pain. Spine, 31(19). doi:10.1097/01.brs.0000232787.71938.5d
- Ferreira, M. L., Ferreira, P. H., Latimer, J., Herbert, R. D., Hodges, P. W., Jennings, M. D., . . . Refshauge, K. M. (2007, 09). Comparison of general exercise, motor control exercise and spinal manipulative therapy for chronic low back pain: A randomized trial. Pain, 131(1), 31-37. doi:10.1016/j.pain.2006.12.008
- Ferreira, P. H., Ferreira, M. L., Maher, C. G., Herbert, R. D., & Refshauge, K. (2006). Specific stabilisation exercise for spinal and pelvic pain: A systematic review. Australian Journal of Physiotherapy, 52(2), 79-88. doi:10.1016/s0004-9514(06)70043-5
- França, F. R., Burke, T. N., Hanada, E. S., & Marques, A. P. (2010). Segmental stabilization and muscular strengthening in chronic low back pain: A comparative study. Clinics, 65(10), 1013-1017. doi:10.1590/s1807-59322010001000015
- George, S. Z., Childs, J. D., Teyhen, D. S., Wu, S. S., Wright, A. C., Dugan, J. L., & Robinson, M. E. (2011, 11). Brief psychosocial education, not core stabilization, reduced incidence of low back pain: Results from the Prevention of Low Back Pain in the Military (POLM) cluster randomized trial. BMC Medicine, 9(1). doi:10.1186/1741-7015-9-128
- Gomes-Neto, M., Lopes, J. M., Conceição, C. S., Araujo, A., Brasileiro, A., Sousa, C., . . . Arcanjo, F. L. (2017, 01). Stabilization exercise compared to general exercises or manual therapy for the management of low back pain: A systematic review and meta-analysis. Physical Therapy in Sport, 23, 136-142. doi:10.1016/j.ptsp.2016.08.004
- Hodges, P. W., Moseley, G. L., Gabrielsson, A., & Gandevia, S. C. (2003, 07). Experimental muscle pain changes feedforward postural responses of the trunk muscles. Experimental Brain Research, 151(2), 262-271. doi:10.1007/s00221-003-1457-x
- Javadian Y, Akbari M, Talebi GA, et al. (2015) Influence of core stability exercise on lumbar vertebral instability in patients presented with chronic low back pain; A randomized clinical trial. Caspian J Intern Med, 6(2): 98-102.
- Kachanathu, S. J., Zakaria, A. R., Sahni, A., & Jaiswal, P. (2012). Chronic Low Back Pain in Fast Bowlers a Comparative Study of Core Spinal Stabilization and Conventional Exercises. Journal of Physical Therapy Science, 24(9), 821-825. doi:10.1589/jpts.24.821
- Koumantakis, G. A., Watson, P. J., & Oldham, J. A. (2005, 06). Supplementation of general endurance exercise with stabilisation training versus general exercise only. Clinical Biomechanics, 20(5), 474-482. doi:10.1016/j.clinbiomech.2004.12.006
- Lehman, G. (2012) CORE STABILITY AND PAIN: IS IT TIME TO STOP USING THE WORD STABILITY TO EXPLAIN PAIN?
- Lehman, G. (2013) CORE STABILITY AND LOW BACK PAIN: HOW STABILITY EXERCISES MIGHT HELP. PART TWO
- Lederman, E. (2010, 01). The myth of core stability. Journal of Bodywork and Movement Therapies, 14(1), 84-98. doi:10.1016/j.jbmt.2009.08.001
- Macedo, L. G., Maher, C. G., Latimer, J., & Mcauley, J. H. (2009, 01). Motor Control Exercise for Persistent, Nonspecific Low Back Pain: A Systematic Review. Physical Therapy, 89(1), 9-25. doi:10.2522/ptj.20080103
- May, S., & Johnson, R. (2008, 09). Stabilisation exercises for low back pain: A systematic review. Physiotherapy, 94(3), 179-189. doi:10.1016/j.physio.2007.08.010
- Palekar, T.J. & Das, A.K. & Pagare, V.K.. (2015). A comparative study between core stabilization and superficial strengthening exercises for the treatment of low back pain in two wheeler riders. International Journal of Pharma and Bio Sciences. 6. B168-B176.
- Prieske, O., Muehlbauer, T., & Granacher, U. (2015, 11). The Role of Trunk Muscle Strength for Physical Fitness and Athletic Performance in Trained Individuals: A Systematic Review and Meta-Analysis. Sports Medicine, 46(3), 401-419. doi:10.1007/s40279-015-0426-4
- Puntumetakul, R., Areeudomwong, P., Emasithi, A., & Yamauchi, J. (2013, 11). Effect of 10-week core stabilization exercise training and detraining on pain-related outcomes in patients with clinical lumbar instability. Patient Preference and Adherence, 1189. doi:10.2147/ppa.s50436
- Reed, C. A., Ford, K. R., Myer, G. D., & Hewett, T. E. (2012, 08). The Effects of Isolated and Integrated ‘Core Stability’ Training on Athletic Performance Measures. Sports Medicine, 42(8), 697-706. doi:10.2165/11633450-000000000-00000
- Saragiotto, B. T., Maher, C. G., Yamato, T. P., Costa, L. O., Costa, L. C., Ostelo, R. W., & Macedo, L. G. (2016, 01). Motor control exercise for chronic non-specific low-back pain. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.cd012004
- Selkow, N. M., Eck, M. R., & Rivas, S. (2017, 12). Transversus Abdominis Activation And Timing Improves Following Core Stability Training: A Randomized Trial. International Journal of Sports Physical Therapy, 12(7), 1048-1056. doi:10.26603/ijspt20171048
- Shamsi, M. B., Rezaei, M., Zamanlou, M., Sadeghi, M., & Pourahmadi, M. R. (2016, 02). Does core stability exercise improve lumbopelvic stability (through endurance tests) more than general exercise in chronic low back pain? A quasi-randomized controlled trial. Physiotherapy Theory and Practice, 32(3), 171-178. doi:10.3109/09593985.2015.1117550
- Shnayderman, I., & Katz-Leurer, M. (2012, 07). An aerobic walking programme versus muscle strengthening programme for chronic low back pain: A randomized controlled trial. Clinical Rehabilitation, 27(3), 207-214. doi:10.1177/0269215512453353
- Smith, B. E., Littlewood, C., & May, S. (2014, 12). An update of stabilisation exercises for low back pain: A systematic review with meta-analysis. BMC Musculoskeletal Disorders, 15(1). doi:10.1186/1471-2474-15-416
- Steiger, F., Wirth, B., Bruin, E. D., & Mannion, A. F. (2011, 11). Is a positive clinical outcome after exercise therapy for chronic non-specific low back pain contingent upon a corresponding improvement in the targeted aspect(s) of performance? A systematic review. European Spine Journal, 21(4), 575-598. doi:10.1007/s00586-011-2045-6
- Stuber, K. J., Bruno, P., Sajko, S., & Hayden, J. A. (2014, 11). Core Stability Exercises for Low Back Pain in Athletes. Clinical Journal of Sport Medicine, 24(6), 448-456. doi:10.1097/jsm.0000000000000081
- Sung, P. S. (2013). Disability and back muscle fatigability changes following two therapeutic exercise interventions in participants with recurrent low back pain. Medical Science Monitor, 19, 40-48. doi:10.12659/msm.883735
- Vasseljen, O., Unsgaard-Tøndel, M., Westad, C., & Mork, P. J. (2012, 06). Effect of Core Stability Exercises on Feed-Forward Activation of Deep Abdominal Muscles in Chronic Low Back Pain. Spine, 37(13), 1101-1108. doi:10.1097/brs.0b013e318241377c
- Wang, X., Zheng, J., Yu, Z., Bi, X., Lou, S., Liu, J., . . . Chen, P. (2012, 12). A Meta-Analysis of Core Stability Exercise versus General Exercise for Chronic Low Back Pain. PLoS ONE, 7(12). doi:10.1371/journal.pone.0052082
- Wang, X., & Chen, P. (2014, 05). Core Stability Exercise Versus General Exercise For Chronic Low Back Pain Meta-analysis. Medicine & Science in Sports & Exercise, 46, 505. doi:10.1249/01.mss.0000494982.79731.79
- Wirth, K., Hartmann, H., Mickel, C., Szilvas, E., Keiner, M., & Sander, A. (2016, 07). Core Stability in Athletes: A Critical Analysis of Current Guidelines. Sports Medicine, 47(3), 401-414. doi:10.1007/s40279-016-0597-7
- Wong, A. Y., Parent, E. C., Funabashi, M., & Kawchuk, G. N. (2014, 04). Do Changes in Transversus Abdominis and Lumbar Multifidus During Conservative Treatment Explain Changes in Clinical Outcomes Related to Nonspecific Low Back Pain? A Systematic Review. The Journal of Pain, 15(4). doi:10.1016/j.jpain.2013.10.008
- Wong, A. Y., Parent, E. C., Funabashi, M., Stanton, T. R., & Kawchuk, G. N. (2013, 12). Do various baseline characteristics of transversus abdominis and lumbar multifidus predict clinical outcomes in nonspecific low back pain? A systematic review. Pain, 154(12), 2589-2602. doi:10.1016/j.pain.2013.07.010