Brace yourself! Or don’t, because it may be a waste of time. Either way, we’re about to talk about the importance (or lack thereof) of core strength, core stability, core training and core “whatever else.” And it’s going to be controversial. Before we dive in, let me tell you a bit about myself and my history with core training. When I was in chiropractic college, I used to perform Stuart McGill’s “Big Three” core exercises on a regular basis. When I started to treat patients with low back pain (LBP), it seemed every patient had decreased activation of the “core” muscles (usually transversus, obliques and multifidi), so every LBP patient received core training. Heck, I even gave core exercises to people with things like shoulder, hip and knee pain. Nowadays? I very rarely perform dead bugs, bird dogs, side bridges or curl-ups. I rarely give them to LBP patients (maybe 1/10 patients). Why the change? I listened to people far more intelligent than me, read the research myself, and finally wised up.
“Whatever, I’m holding this until you convince me otherwise” – random lady doing core work
So how did the whole core stability thing start? Vladimir Janda was probably the first to propose the idea that alterations in trunk muscle activity may lead to back problems. [i] Which I fully admit, sounds very plausible (I used to be a huge Janda fan). Then, studies by Jull and Hodges showed that individuals with low back pain had delayed core muscle activity compared to patients without pain, namely the transversus abdominus (TrA). [ii] [iii] Man, this core stability idea seems even more plausible, right? Then, researchers found a whole bunch of people with LBP (there’s a lot of them out there) and started to compare core stabilization exercises vs. traditional treatments such as general medical care[iv], medications[v], manual therapy[vi] and physical therapy[vii]. And core stability training won, every single time. So time to change the title of this blog and go back to core exercises? Nope.
First, let’s go back to the delayed muscle activation. This delay is about 20 ms, or 1/50th of a second. That’s a very small amount of time. Nonetheless, it was a statistically significant difference. But what happens if we take pain free individuals and induce pain? TrA goes from having no delay to having that same 20 ms delay.[viii] That’s right, by injecting a little bit of saline solution in the low back which gives the patient temporary low back pain, core activation becomes altered. What happens once the pain wears off? The muscle activity goes back to normal. So, pain isn’t the result of altered core activation, it’s the cause! We also see this same delay in pain free individuals when there is an anticipation of pain as well![ix] So what’s going on? This delay results as a protection measure for the spine. If your nervous system detects pain or the threat of pain, it alters the way the muscles fire to protect your low back. It is no different than trying to jump with a painful knee. Your body will jump differently with a painful knee than it would with a pain-free knee, in order to protect the knee. So core stability training to improve this delay is a complete waste of time.
But what about all those studies where core stability training helped with low back pain? Well, those studies were all done compared to mostly passive treatments. What happens when we compare it to other exercise types? It leads to the same outcome, every single time. [x],[xi],[xii] Let’s look at what the authors of a recent research review[xiii] concluded when looking at the evidence:
“There is strong evidence stabilisation exercises are not more effective than any other form of active exercise in the long term. […] and further research is unlikely to considerably alter this conclusion.”
Pretty harsh words, right? Let’s look at it a more positive way though. Stabilization exercises are JUST as effective as any other exercise for low back pain. And we know exercise is the most effective treatment for low back pain. Better than rest, surgery, injections, medications, manipulations… anything.
OK, so what if you don’t care about anything other than straight up athletic performance? You just want to be a cheetah on the track or a gorilla in the gym? Well, one study showed that core training does not improve running economy or VO2 max. [xiv] A second study had participants perform eight weeks of core training and found no improvements in vertical jump, broad jump, shuttle run, 40-m sprint, overhead medicine ball throw or a 2,000m max-effort row. [xv] Another study came to the following conclusion: “Despite the emphasis fitness professionals have placed on functional movement and core training for increased performance, our results suggest otherwise.”[xvi] If you want to get better at running, run and do running specific exercises. If you want to become more powerful, train with more powerful movements.
So, is there any reason to still do core stability exercises? I think so. First, if you love doing core stability exercises, keep doing them. Never stop doing any exercise you enjoy unless it causes pain. Secondly, if you aren’t exercising at all, they are a good place to start. There’s low risk of injury and you can perform them basically anywhere. Third, I do use it with some patients to train how to maintain a neutral spine while dealing with an acute injury that needs a little time to heal. However, it’s more about maintaining good spine position and not about “activating” the core. Finally, I do use them for patients who become pain free but then test for low lumbar muscular endurance. Low lumbar endurance has been shown to be associated with a risk of future low back pain,[xvii][xviii] so improving endurance should theoretically decrease that risk. But I could be wrong. Like when I used to think low back pain was caused by core instability and gave everybody core exercises.
[i] Janda V (1978) Muscles, central nervous motor regulation and back problems. In: Korr IM (ed) The neurobiologic mechanisms in manipulative therapy. Plenum, New York, pp 27–41
[ii] Hodges, P.W. and C.A. Richardson, Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominis. Spine, 1996. 21(22): p. 2640-50.
[iii] Hodges, P.W. and C.A. Richardson, Delayed postural contraction of transversus abdominis in low back pain associated with movement of the lower limb. J Spinal Disord, 1998. 11(1): p. 46-56.
[iv] O’Sullivan, P.B., et al., Evaluation of specific stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolisthesis. Spine, 1997. 22(24): p. 2959-67.
[v] Hides, J.A., G.A. Jull, and C.A. Richardson, Long-term effects of specific stabilizing exercises for first-episode low back pain. Spine, 2001. 26(11): p. E243-8.
[vi] Goldby, L.J., et al., A randomized controlled trial investigating the efficiency of musculoskeletal physiotherapy on chronic low back disorder. Spine, 2006. 31(10): p. 1083-93
[vii] Stuge, B., et al., The efficacy of a treatment program focusing on specific stabilizing exercises for pelvic girdle pain after pregnancy: a two-year follow-up of a randomized clinical trial. Spine, 2004. 29(10): p. E197-203.
[viii] Hodges PW, Moseley GL et al. Experimental muscle pain changes feedforward postural responses of the trunk muscles. Exp Brain Res. 2003; 151(2): 262-71
[ix] Moseley GL, Nicholas MK, Hodges PW. Does anticipation of back pain predispose to back trouble? Brain 2004; 127(Pt 10): 2339–2347.
[x] Nilsson-Wikmar, L., et al., 2005. Effect of three different physical therapy treatments on pain and activity in pregnant women with pelvic girdle pain: a randomized clinical trial with 3, 6, and 12 months follow-up postpartum. Spine 30 (8), 850e856
[xi] Franke, A., et al., 2000. Acupuncture massage vs Swedish massage and individual exercise vs group exercise in low back pain suffererse a randomized controlled clinical trial in a 2 2 factorial design. Forsch Komplementarmed Klass Naturheilkd 7 (6), 286e293
[xii] Cairns, M.C., Foster, N.E., Wright, C., 2006. Randomized controlled trial of specific spinal stabilization exercises and conventional physiotherapy for recurrent low back pain. Spine 31 (19), E670eE681.
[xiii] Smith et al. At update of stabilization exercises for low back pain: a systematic review with meta-analysis. BMC Musculoskeletal Disorders 2014, 15:416
[xiv] Stanton R, Reaburn PR, Humphries B. The effect of shortterm Swiss ball training on core stability and running economy. J Strength Cond Res 2004; 18 (3): 522-8
[xv] Tse MA, McManus AM, Masters RS. Development and validation of a core endurance intervention program: implications for performance in college-age rowers. J Strength Cond Res 2005; 19 (3): 547-52
[xvi] Okada T, Huxel KC, NEsser TW. Relationship between core stability, functional movement and performance. J Strength Cond Res. 2011; 25(1): 252-261
[xvii] Abdelraouf OS, Abdel-azien AA. The relationship between core endurance and back dysfunction in collegiate male athletes with and without nonspecific low back pain. Int J Sports Phy Ther. 2016; 11(3): 337-344.
[xviii] Luoto S, Heliovaara M et al. Static back endurance and the risk of low-back pain. Clinical Biomechanics. 1995; 10(6): 323-324