Core training is a hot trend in the fitness industry, with group exercise instructors and personal trainers having their clients perform a variety of ab-torching and butt-burning workouts. Despite the popularity, does “core training” have any benefits in improving performance and movement, and does it prevent or reduce the risk of back pain? Could most fitness teachers and personal trainers be wrong about the benefits and the approach to core training?
For years, many personal fitness trainers, strength coaches, and physical therapists have suggested that bracing the muscles around the trunk like a corset can improve core muscle function and maybe prevent or reduce chronic low back pain. These core muscles usually refer to the transversus abdominis, internal and external obliques, the rectus abdominis (the six-pack) and multifidi, as shown in an excerpt from Core Assessment and Training on Human Kinetic’s webpage. However, some research has shown that this approach to core training could be wrong and incomplete, and the fitness and physical rehabilitation industry may need to update their knowledge and alter their viewpoints on core training.
The concepts of core training, which include “hollowing” or “drawing in” of the abdominal muscles or tightening the trunk muscles prior to movement, permeate in most personal training certifications and the fitness industry. Such examples of core training can be seen in some certification handbooks, such as the ones from the National Academy of Sports Medicine (NASM). In its core training chapter, the drawing-in maneuver is used to “recruit the local core stabilizers by drawing the navel in toward the spine,” while the bracing involves contracting the lower back, abdominal, and buttock muscles at the same time. But does activating these core muscles consciously really improve strength and function or prevent or reduce low back pain? Current research says not necessarily.
A 2013 meta-analysis published in PLOS One reviewed five studies consisting a total of 414 participants that analyzed whether core stability training or general exercise training is better for chronic low back. Core stability exercises usually include a Swiss ball, wobble board, or low-density mat. The researchers found that core training is better than general exercise training for short-term pain relief. At about six or 12 months, however, there were no significant differences between both groups for long-term pain relief. Even so, the data collected were of low quality due to small sample populations and inconsistent interventions in the experimental setup in each of the five studies.
Dr. Peter O’Sullivan, Ph.D., who is a professor of musculoskeletal physiotherapy at Curtin University in Perth, Australia, stated that chronic low back pain is complex and stems from so many different causes that no one single method of exercise therapy, including core training, can treat all cases. While some causes of low back pain are caused by biomechanical factors, such as nerve impingement or tense muscles, other causes could stem from stress, chemicals (i.e. cancer), or nerve pathways. O’Sullivan emphasized that the biopsychosocial model should be used to address chronic low back pain. This model takes the “physical, lifestyle, neuro-physiological, psychosocial and genetic factors” that can contribute to pain.
Despite the evidence suggesting that strengthening the core have limited effects on those with chronic back pain, the belief that core training is a “magic bullet” cure or prevention to low back pain is still widespread. There are some plausible reasons why some fitness trainers and medical professionals think so. O’Sullivan wrote in an editorial in British Journal of Sports Medicine (August 2011) that many of the core training with low back pain studies with small sample populations were applied to the much broader chronic low back pain populations “without the results of these studies being reproduced in these populations or in larger groups.” O’Sullivan added that single-method approach to treat low back pain could make the pain worse, causing a continuous pain cycle. The reductionist model of managing and treating low back pain fails to address the psychological, environmental, and chemical factors that can contribute to the disorder. For some people, no amount of core training could improve or prevent chronic low back pain, which could be a wrong method for personal fitness trainers to do.
The biomechanical approach does not address why some pregnant women have reduced back pain with reduced core muscle strength.
In a critical review written by physiotherapist Eyal Lederman, D.O., Ph.D., in The Journal of Bodywork and Movement Therapies, he stated that most women who had given just given birth had weakened abdominal and pelvic floor muscles, yet most of them have reduced back pain. This is based on a Dutch study published in 2006 in BMC Musculoskeletal Disorders that compared the outcome between biopsychosocial approach to treating back and the traditional model that focused on the lower back and pelvic girdle. Out of 869 women who were suffering from back pain during pregnancy, 635 were excluded from continuing in the study because of their “spontaneous unaided recovery within a week of delivery.” During this period, the abdominal muscles have yet to return to their pre-pregnancy strength, length, and control. Low back pain was much reduced during the recovery period. Lederman asked if the core muscles are weakened and lack control, why was there an improvement in back and pelvic pain? Was the relationship between core muscles and spinal stability over-emphasized?
Lederman also addressed that core exercises are usually performed on a four-point kneeling position, prone position (i.e. planks), or a supine position (i.e situps, leg lifts). The idea is that by strengthening and activating the core muscles with the right timing, movement and performance can be improved. However, it is very unlikely that any significant improvements could be developed because the nervous system and motor control of the muscles and tissues are very movement specific. Strengthening the abdominal muscles by doing sit-ups in hopes of slugging a home run or preventing muscle spasms during stair climbing is like squeezing a rubber ball to strengthen the fingers to play the piano better.
Core training for most weightlifters should be in an upright position, not lying down.
Based on the SAID principle, which stands for “specific adaptation to imposed demands,” the body and the nervous system get better at specifically what they are trained to do. Physical therapist and professional break dancer Tony Ingram, who practices in St. John, Newfoundland and blogs on Bboy Science, said that he did not develop his ability to do a single handstand by doing shoulder presses with weights to strengthen his shoulders. He got better at doing handstands by practicing handstands. Therefore, to improve core function, one must practice specifically in the movement pattern that is close to the actual skill. For example, sprinters and baseball players would need to train mostly in a standing position while yoga novices and wrestlers may need to train in certain ground positions that are specific to their activity.
Even though core training could be overrated in the fitness and physical rehab industry, personal trainers and physical therapists are not completely wrong because there are many ways to address chronic low back pain and low back pain prevention. Physiotherapists Paul Hodges and Lorimer Moseley and four other medical professionals, who co-authored the book Spinal Control: The Rehabilitation of Back Pain, mentioned that the current modalities to exercise management of low back and hip pain can coexist. Rather than focusing on one modality and ignoring the others, professionals should use a variety of modalities and perhaps use one specific modality to “emphasize” in each case. The biomechanical/anatomical and biopsychosocial models can be integrated rather than used in isolation. Therefore, depending on each clients or patient, muscle activation in core training could be useful. However, other factors outside of anatomy should also be addressed, or the practitioner may miss out on the bigger picture of why pain exists.