PT on the Net Research

Core Training and Glute Activation


The following is an excerpt from Mike Boyle’s book Designing Strength Training Programs and Facilities.

Simply defined, core stability or pillar strength is “the ability to create extremity movement without compensatory movement of the spine or pelvis.” In the broadest sense, it is “the ability to produce and transmit force from the ground without energy leaks at the hips, spine or scapulo-thoracic joints.” Energy leaks are defined as points at which energy is lost during the transfer of force from the ground. Energy leaks are a result of the inability of the body to stabilize a particular joint. Torso strength encompasses core, hip and shoulder stability and, most importantly, the ability to move force from the ground to the extremities while maintaining stability in the aforementioned areas.

Setting the Stage for Stability: Training the Deep Abdominal Muscles

As the study of the interrelationship of low back pain and the training of the abdominal muscles continues, it is obvious that the paradigms will continue to shift. One such shift is occurring currently. I have written and spoken extensively about the Australian methods of training the deep abdominal muscles. The work of Richardson, Hodges and Jull, through their landmark work Therapeutic Exercise for Spinal Segmental Stabilization in Low Back Pain, has significantly advanced our knowledge of core anatomy and muscle function. In actuality, that book and the research that preceded it have forever changed the way that training is performed. Interestingly enough, some practitioners in the field have rejected the Australian concepts for a broad range of reasons. The most notable and credible among these critics is Canadian Dr. Stuart McGill. McGill provides a sound biomechanical rationale for why “hollowing,” as he refers to the “draw-in” maneuver, will actually decrease stability. McGill advocates a technique he refers to as “bracing” in place of “hollowing” or “drawing in” (these terms are defined below). I understand Dr. McGill’s premise, but I still believe that learning to hollow or draw in is a necessary skill for our athletes to achieve.

Although I am not qualified to dispute Dr. McGill’s research, I have a point of theoretical disagreement. McGill’s research clearly shows that drawing in or hollowing can decrease base of support and stability of the spine. However, we are teaching drawing in as a neuromuscular awareness exercise, not as the primary vehicle for stability.

In addition, most of our athletes are the classic “Janda lower-crossed body” with an almost protruding abdominal wall and a significant lumbar lordosis. (Vladimir Janda was one of the pioneers of manual medicine in Europe. He introduced many of the concepts of muscle imbalance on which core training and functional training are now based.) In these athletes, I believe that drawing in simply brings the rectus into normal alignment from a position of concavity. In reality, the athlete is not hollowing but simply bringing the abdominal wall back to its intended position of stability. In other words, the goal is simply to bring the abdomen back to its normal anatomical position. The key here is that drawing in for a lordotic athlete would not decrease the base of support as McGill suggests.

In my opinion, performing draw-in exercises literally sets the table for all other stability exercises. We are teaching athletes to contract a muscle they may not be capable of contracting voluntarily. Athletes or clients unable to draw in will not be able to properly stabilize in any other movement pattern. In fact, I don’t believe an athlete who cannot draw in would be able to “brace” as effectively in a natural setting. In my opinion and experience, the purpose of the draw-in exercises is not really to be exercises in themselves but to allow clients to learn to properly set the core musculature in all activities.

Initially the draw-in concept is applied in quadruped or bridging exercises (both of which can be found in the PTontheNET.com Exercise & Flexibility Library). In my opinion, the draw in is the foundation on which all other stability exercise is built. Whether you choose to draw in or brace, the execution of quadruped or bridging exercises remains the same. The difference is not in how you do the exercises, but in how you choose to set the table. The end result remains the same.

The Science Behind Core Training

Torso strength could be a book in and of itself. The training of the torso, core or pillar, depending on your descriptive term of choice, is filled with controversy and confusion. Advocates of powerlifting or Olympic lifting seem to feel that most of the scientific advances made in the areas of medicine and physical therapy do not apply to strength sports. As with many points made by those who consistently lift weights with two feet on the ground, I respectfully disagree. I think our influences in the area of injury prevention should be the physical therapists who deal with injured athletes, not people from the sports of powerlifting or Olympic lifting.

It is very easy for those who never have to worry about athletes running or jumping to tell us how to train those who do. Unfortunately, when powerlifting or Olympic lifting coaches begin to move from strength and power development into performance enhancement, problems arise. In this instance, I believe you cannot deny science. Science tells us that the deep abdominal muscles (internal oblique, transverse abdominus and multifidus) play a key role in the stability of the lumbar spine. Many in the strength community disagree. I believe that disagreement is healthy, but I have seen far too many strength athletes with problems in the lumbo-pelvic hip complex (hip and low back) to think that exercises like squats provide enough stability training to the core.

I have come to believe that learning to stabilize either via a bracing maneuver as described by McGill (simultaneous use of the rectus abdominus and the deep abdominal musculature) or by executing a draw-in maneuver is key to being able to strength train and remain healthy. Many who have read my work might consider this a departure from my previous thoughts. In fact, it is only the continuation of my education. Six years ago, I did not have nearly the depth of understanding on the anatomy of the deep abdominal musculature as I do now. McGill’s work has continued to advance our knowledge of the workings of the abdominal musculature, and I must admit his evidence is compelling. Dr. McGill’s Low Back Disorders is the latest landmark work for any strength and conditioning professional. I think the disagreements between people like McGill and Hodges are primarily disagreements of semantics as they relate to strength training and not really of science. The Australian research in the area of drawing in is still applicable to athletes because, as I stated previously, most athletic bodies are lordotic.

As I have continued to read the work of physical therapist Shirley Sahrmann, I have also changed my ideas on the training of “local muscles” versus “global muscles.” In her book Diagnosis and Treatment of Movement Impairment Syndromes, Sahrmann makes some interesting comments relative to core training as it relates to the larger muscles, like the external oblique and internal oblique. Sahrmann has isolated the essence of any exercise but, most importantly, core exercise. Sahrmann states: “Motion is restricted to the segment that is supposed to move.” Like McGill, Sahrmann relies heavily on EMG data to prescribe exercise, but her prescriptions run away from the norm. Sahrmann recommends a traditional abdominal curl-up as a segmental movement not directed primarily at the rectus but at the internal oblique.

In fact, Sahrmann states, “The primary disadvantage of improving the rectus abdominus is that the rectus cannot produce or prevent rotation, and shortness or stiffness contributes to thoracic kyphosis.” However, the data Sahrmann cites shows that the highest internal oblique activity is actually when a curl-up or segmental crunch is progressed into a full sit-up. Sahrmann makes clear distinctions as to how this should be performed with internal oblique focus and makes a wonderful case for including an “old school” exercise in the torso strength program. Sahrmann also cites the reverse crunch as a key external oblique exercise. This is a hips-to-shoulders flexion exercise that elicits high external oblique activity.

Glute Activation and Injury Prevention

To really understand core training, we need to look at the key compensation patterns that occur when someone attempts to train the core. As I often state in my work, substituting lumbar extension for hip extension is the major culprit in many of the problems that we see. This is one of the primary problems in lower back pain and may be one of the key areas we attempt to improve over the next few years. McGill uses the term “gluteal amnesia.” Mike Clark might call it a problem of reciprocal inhibition or synergistic dominance. Both are “Jandaists." Both McGill and Clark identify the same problem. The problem is, are the glutes weak because the psoas is tight, or is the psoas tight because the glutes are weak? It may be a classic interdependent, chicken and egg scenario. Either way, proper strengthening of the glutes will be the best cure. In fact, we may not even be strengthening but just re-educating the neuromuscular system. In reality, most early strength gains are more neural than contractile.

In order to do this, the athlete needs to be able to set the core and fire the glutes. Initially, this is best done in quadruped to eliminate hamstring contribution. Sahrmannn presents another series of thoughts in her book. She believes most anterior hip pain is also the result of poor glute function and the resultant synergistic dominance of the hamstrings. Sahrmann discusses the simple biomechanical explanation by citing the lower insertion point of the hamstrings on the femur. If the hamstrings are consistently called upon to be the primary hip extensor, the result will be anterior hip pain in addition to hamstring strains. The anterior hip pain is a result of the poor angle of pull of the hamstrings when used as a hip extensor.

The key to the future of torso or core training will be in combining all of the necessary movements without overemphasizing or underemphasizing a particular muscle or movement. If I look at my failings over the last five years, I would say that it would be in not training the larger global muscles. So much emphasis was placed on draw-in exercises and on stability that many of athletes could not perform sit-up or curl-up exercises. If I can make one clear statement of what I believe now about training, particularly as it applies to the core or pillar, it is "Glute activation or more importantly, lack of glute activation, may be the root of many of our evils."

As we look at more and more athletes, both injured and healthy, the inability to activate the gluteus maximus and gluteus medius stands out as the root cause of at least four major injuries:

  1. Low back pain relates strongly to poor glute max activation. (Poor glute function will cause excessive lumbar compensation.)
  2. Hamstring strains relate strongly to poor glute max activation. (Think about synergistic dominance.)
  3. Anterior hip pain relates strongly to poor glute max activation. (This relates to the poor biomechanics of hamstrings as hip extensors.)
  4. Anterior knee pain relates strongly to poor glute medius strength or activation.

Sahrmann makes one of her many lucid points: “When assessing the factors that contribute to an overuse syndrome, one of the rules is to determine whether one or more of the synergists of the strained muscle are also weak. When the synergist is weak, the muscle strain is probably the result of excessive demands.”

I call this looking on the roof. If you see water leaking into your house, you don’t simply try to plug the hole or paint over the water stain. You look for the source of the water. You look on the roof for the problem. The same applies to injuries. Don’t focus on pain site - focus on the pain source. In our case, the source keeps coming back to the glutes. In the bigger picture, coaches should look at every non-traumatic (non-contact) injury as having a root cause in either poor program design or weakness of synergists.

We perform glute activation at the beginning of every workout to develop better awareness of the function of the glutes and to hopefully “wake them up” so that they will be greater contributors to the workout.

This whole “glute activation” thing can become a problem as you will be asking your athletes or clients to continually touch their rear ends. In addition, you will be continually touching people’s rear ends. A word to the wise: In our litigious society, sexual harassment is a problem. Be careful and communicate clearly. We are treading in dangerous, but necessary, water.

One small problem: When does glute activation become resistance training versus core training? I must confess to being unsure at this point. There is a thin line between hip-dominant exercise and core training. The solution may be to do your core work (quadruped and bridging) on the days you are doing your hip-dominant lower-body exercises or perhaps to perform some type of hip-dominant exercise every day. Whatever your approach, let me be clear that I believe it is vital to perform glute activation prior to every workout.

Glute Activation Keys

Figure 1: X Band Walks Figure 2: Quadruped Hip Extension Figure 3: Cook Hip Lift

Glossary of Terms