Tree Stump Training and Initials: Mechanisms of Injury Susceptibility: Part 2

Andrew Charniga

“Experience without theory is blind, but theory without experience is mere intellectual play”. Immanuel Kant

A group of essays concerning the epidemic of injuries in American sport; especially of the lower extremity; have established a cause and effect connection between susceptibility to injury and the incongruous amalgamation of strength and conditioning coaches, academics, athletic trainers, physical therapists, doctors, exercise charlatans, made for sale training methods, systems, and so forth.

To make such a claim; to lay blame at the doorstep so many educated people; for the damage they are directly and indirectly responsible; it is necessary to make a case as to how the misguided beliefs and practices of all these professionals are linked. 

A number of commonly accepted beliefs emanate from ‘facts’ found in academic publications; and/or textbooks and likewise certifications of such knowledge sold by professional organizations. These organizations certify expertise through the sale of knowledge; while at the same time providing the certified coaches and trainers who take their courses convenient access to exercise equipment vendors who pay fees to attend their national conferences, i.e., a contradictory conflict of interest.That is to say, these organizations promote the sale their certification knowledge along with equipment developed and sold by vendors with little or no experience in the field.  

At the risk of being overly simplistic; in most respects, many of the frequently occurring lower extremity injuries such as Achilles rupture, plantar fascia tear, high ankle sprain, inversion sprain, ACL tear and related knee injuries, foot injuries:  Jones, Lisfranc, pedal foot fracture, tibial plateau fracture; have many precipitating circumstances in common, i.e., a consilience of induction links the circumstances which confirms the theory as to the root cause and reasons for the injury epidemic.

Physiological Factors of Injury Susceptibility

/ a connection between a varying proportion of connective tissue in muscles with the potential to increase dynamic resistance;

Lower extremity muscles tend to contain more connective tissue than upper extremity musculature; more connective tissue means the muscles exhibit higher passive resistance to stretching (Latash, Zatsiorksy, 2016). Additional resistance to the ability of muscles to stretch in dynamic sports; where running, jumping, reactions while cutting, falling, tackling and so forth can be a factor to bear in mind; since the athlete’s lower extremity muscles are typically trained to resist large range of motion in joints (see Charniga, “Why safe is unsafe”,

The larger relative composition of connective tissue in lower extremity muscles tends to raise resistance to passive stretching forces encountered in dynamic sport. This fact should be a consideration in strength and conditioning and rehabilitation. A large number of repetitions per set, willful slow movement in strength exercises, prolonged straining at heavy weights, exercises to fatigue (i.,e bodybuilding/powerlifting) would tend to compound the larger proportion of connective tissue present in lower extremity musculature; exacerbating resistance to passive stretching (Gudz, 1975) .

Any technique or method of exercising which can potentially compromise an athlete’s ability to quickly react with lengthening of muscles, tendons, ligaments, bending or bowing of joints; is not a good idea for any anyone who competes in dynamic sport. All the more so, with exercises accentuating lower extremity musculature; which are already comprised of larger portions of connective tissue.    

/  affect of co – contraction of muscle antagonists to raising dynamic and passive resistance to stretching muscles;

A certain amount co – contraction of antagonist muscle pairs is a natural consequence of any movement. For instance, there must be back some round co – contraction of antagonists in throwing movements, such as triceps and biceps muscles. An optimum co – contraction of the aforesaid muscles permit the desired effect. However, excess tension in say the biceps as the arm extends in throwing will tend to adversely affect the outcome.

Figure 1. Straining against a backdrop of low backround static (excess co – contraction of muscle antagonists) is kinematically more efficient (Latash, Zatsiorksy, 2016). Charniga photo

Excessive co – contraction of muscle antagonists can increase resistance to rapid bending – flexing movements characteristic of dynamic sports. One can cultivate unnecessary co – contraction of muscle antagonists to dynamic movements as a result of chronic training with isometric exercise conditions, such as prolonged straining with heavy weights, exercises performed slowly, exercises to fatigue, i.e., building up ‘back round’ noise. Co – contraction of antagonistic pairs  is kinematically inefficient and “ineffective in counteracting perturbation of equilibrium” (Latash, Zatsiorsky, 2016) {see figure}

Figure 2 . Straining with minimal tension from co – contraction of antagonist muscles  (back – round static) is kinematically more efficient. Charniga photo.

Consequently, it is logical, those athletes who are able perform exercises with less back round static, i.e., with low tension from co – contraction of antagonist muscles; are more efficient (Vorobeyev, Latash, Zatsiorsky, Falameyev et al). Hence, a positive transfer to the athletic field can be expected of qualities developed from exercises performed in the gym with low back round static, i.e., excess co – contraction of antagonists .

For instance, the rapid switching of directions, from lifting to descending characteristic of high class weightlifters is not possible with excess tension in the form of co – contraction of muscle antagonists. The back round static would slow the weightlifter’s ability to relax muscles and move rapidly without superfluous internal resistance to joint mobility. The same principle applies to other dynamic sports:     

“…atypical pre – programmed reactions represent simultaneous activation responses in agonist – antagonist muscle pairs (Horak, and Nashner, 1986) Such responses increase the apparent stiffness of the joint crossed by the muscles and reduce kinematic effect’. (Latash, Zatsiorsky 2016).

/ physiological hazards of straightening lower extremities;

There are many instances in dynamic sports such as football, basketball, soccer where an athlete extends one leg near, or, to full extension of the knee in running; planting the foot heel first: “reaching at 180º planting heel to toe” (Charniga, 2020). An instant later the athlete experiences a serious knee injury such as a ACL tear as he/she transitions from extending the leg to flexing to continue moving forward, i.e., a problem connected with flexing lower extremities (see Charniga, “Nine straps”,

Conversely, most hamstring injuries occur in what is called the late swing phase of sprinting/running as the leg straightens, i.e., an injury connected with straightening lower extremities. Considerable literature attributes the hamstring injury to a lack of eccentric strength in the hamstring group. If the hamstrings were just stronger, so the thinking goes; they would be able to withstand the strain of the rapid extension of the leg in reaching for ground contact. 

However, just increasing the strength of the hamstring group; especially with simple muscle contraction exercises (see Charniga, “Hamstring injury in sport”, “Hamstring injury: Prophylaxis fallacies”, does not address the underlying physiological mechanism. A rapidly straightening of the leg immediately preceding ground contact (late swing phase of sprinting); when hamstring injury occurs most frequently; is connected with rising resistance to passive stretching of muscles:   

“Elastic resistance increases exponentially as joint motion approaches its maximal limit.” (Latash, Zatsiorsky, 2016)

Consequently, a simplistic approach based on an underlying false assumption the main culprit of injury to hamstring group is a lack of strength; irregardless if it is eccentric or concentric strength. Just increasing strength of the hamstring group discounts the underlying physiological mechanism of rising elastic resistance as the knee joint nears a fully extended position just before ground contact.

A supra – stretching regimen to address the underlying physiology of an “exponential” rise in elastic resistance as the joint nears full extension was proposed (Charniga, 2021); which is, by far, a more logical approach than the commonly applied muscle shortening exercises with machines, or, lying face down on the floor.

The prevalent solution to be found in the literature to the heightened susceptibility of hamstring injury in the late swing phase of running (as the leg nears full extension)  is to simply increase the strength of these muscles. Such a simplistic approach discounts an underlying physiological mechanism for an “exponential rise in elastic resistance”. Why does such a mechanism exists in the first place?

According to this line of thinking, increasing the strength of hamstring muscles will resist the heightened elastic resistance as the knee nears full extension? Were that the solution a significant decrease in hamstring injury rate would result as this idea has been around forever. However, there is no evidence injury rate has decreased as a result of strengthening the hamstring group.

/ “Act of will” versus reflexes;

An action is an “act of will” (Merriam Webster). There exist too many to list examples of exercise techniques where athletes are taught deliberate step – by – step, “act of will” movement patterns. Act of will movement patterns for common conditioning exercises can be found in many texts, certification courses, videos, and the like; such that, most everyone in the strength and conditioning, fitness, rehab communities teach essentially the same thing. An example of act of will exercise technique for performing the power clean with a barbell:

“tight core”; flat neutral back; drive through the heels; knees behind the toes; move bar in straight line; 

None of the nonsensical instructions listed are correct. Yet they reflect prevailing attitudes: man made, step – by – step protocols requiring act of will movement patterns to perform complex exercises. It is simply not possible to follow the aforesaid instructions while at the same time performing complex coordination exercises. However, this is no deterrence to those who prescribe act of will techniques (see figure below of textbook instructions of power clean exercise). 

Figures 3 -4. Two examples of (figure above) incorrect textbook act of will technique and (figure below) correct technique of fixing a weight on the chest for a power clean. Lower figure Charniga photo. 

The two figures illustrate two distinct methods of receiving the weight at the chest for the power clean. In the first figure the textbook/certification course instructions to “avoid moving the knees forward while entering the squat” are consistent with the instructions above “knees behind toes”; an indication most everyone of the academic community are on the same page in terms of act of will technique; which in the examples presented are instructions for flexing lower extremities, i.e, a tree stump technique.

In the textbook example (figure 3), an act of will technique is stipulated to purposefully keep shins from moving forward; even if it means subjecting the lumbar spine to an unjustified shear strain by leaning forward to receive a weight on the chest. Hence, an illogical false narrative is proposed that it is safer to subject the lumbar spine to unjustified strain in order to ‘protect’ the knees by freezing the ankle joints, i.e., with tree stump training.  

It is known approximately 70% of a person body mass is situated above the pelvis; which in its turn, means the lean forward at the waist ‘act of will’ technique compounds the strain in the  lumbar area; all the more so because the curves of the spine are designed to mitigate forces with the trunk in a vertical disposition; not a horizontal disposition.

Tilting forward to avoid flexing of lower extremities: is a tree stump technique requiring act of will. It just so happens to be identical to differences in reactions  between young and older people to perturbance in equilibrium.

The act of will technique of the power clean recommended by academia in figure 3 happens to be strikingly similar to an older person’s reaction to loss of equilibrium: to bend from the waist (see next section).

The correct technique to receive the weight on the chest is to flex knees and especially ankles; such that the spine is reasonable vertical to receive the barbell on the chest; which greatly mitigates the strain on  the lumbar area (see female weightlifter figure 4). The forces on the body are best distributed and amortized by flexing the leg springs; not by tilting forward at the waist.

Act of will exercise techniques; especially as it applies to the examples tree stump training; more often than not function to precipitate injury; not mitigate injury susceptibility.             

/  natural and unnatural aging effecting mechanisms of equilibrium;

Evidence exists aging can affect how humans react to disturbances in equilibrium. Younger subjects tend react to disturbance in equilibrium by activating muscles distal – proximal; which means the young subject reacts by bending with an “ankle strategy” with Tibialis anterior and other ankle muscles first, to re – restore balance. Conversely, older subjects react to disturbances in equilibrium with the opposite strategy: proximal – distal activation of musculature. That older subjects react with a “hip strategy” i.e., from the hip down; has implications for injury susceptibility as this happens to coincide with a loss of joint mobility with aging (Latash, Zatsiorsky, 2016).

These reactions to disturbances in equilibrium are diametric opposites: young people will tend react to loss of balance in the saggittal plane (fore – aft direction) by first bending lower extremities at the ankle joint and tilting trunk backwards opposite the movement of the shin and thigh; such that the body center of mass remains over the feet. 

By way of contrast, an older person will activate hip and trunk muscles first; tilt the trunk forward with little or no ankle bending; which in turn sends the body center of mass forward in the same plane as equilibrium perturbation. Leaning forward at the waist to prevent falling forward would not seem to be a sound strategy.

A potential take away from this phenomena is the loss of mobility in the ankle joints, muscles, tendons and ligaments compels the older people to react to loss of equilibrium with available mobility and function; and, not necessarily the best strategy for regaining equilibrium. This circumstance may shed light  on why the elderly are more predisposed to injury from falling; with the process of senescence adversely affecting mobility of lower extremities, i.e., from the ground up.  

The implications of an “ankle strategy’ versus a “hip strategy” reactions to perturbations of equilibrium with age; should be a important factor to consider for the ankle tapers and ‘tree stump exercise’ technique devotees. The artificial restriction of ankle joint mobility with either bracing (taping) or artificially restricting movements in lower extremity joints with ‘tree stump exercise’ techniques is akin to hastening the process of aging. Old people tend to react with movements to regain balance from the hip down with forward lean of trunk; which happens to coincide with a general loss of mobility; apparently, all the more so in lower extremities. Activating hip and trunk muscles first; in reaction to perturbations in equilibrium; would appear to be a poor strategy; since at least 70% of the mass of the body is located above the waist:

“The weight of the upper body accounts for almost 70% of the total body weight.” (Clauser, 1969).

That being the case, the typical activities of the ankle taper/tree stump practitioners would tend to accelerate the senescence of the young athlete’s body; which in turn are manifest in the unfortunate circumstances of heightened susceptibility to injury on the athletic field or court.

Figure 5: A youthful  reaction to loss of equilibrium: with ankle strategy. Charniga photo.

That is to say, if a young person’s reaction to disturbances in equilibrium with an ankle strategy is the preferable; then, restricting ankle mobility and likewise learning to control ankle bend in exercises would serve to displace one of nature’s millenniums old safe reactions in the youthful body; replacing it with a man made, debilitating reactiveness of old age. Does that sound right?

/ reactive versus act of will movements;

“No man ever steps in the same river twice, for its not the same river and he is not the same man” Heraclitus

The reason many exercise techniques, especially those taught with superfluous act of will movement patterns are unsafe is the fact they are based on the false assumption one can step in the same river twice and that the same ‘man’ can step in the same river. Where there a shred of truth to this; then nature is in error.

The existence of protective reactive reflexes and innate reactiveness qualities would be unnecessary. Training to develop muscular  strength with simple act of will exercise techniques so that the strength will transfer to dynamic activities in sport is based on the false assumption the conditions on the court or athletic field are predictable: 

“This is clearly impossible given the dependence of all these variables on the current external conditions, which are never 100% predictable.” M.L. Latash, V.M., Zatsiorsky, Biomechanics of Motor Control, 2016

Simple exercises with low, to non – existent coordination structure, machine exercises, exercises performed in racks or otherwise artificially restricting range of movement may instill what constitute “atypical preprogrammed reactions” where co- activation of antagonist pairs cause elevated dynamic resistance; or, in other words, what a number of authors have characterized as internal resistance: 

“Atypical preprogrammed reactions may be seen in many populations characterized by impaired stability of movements including healthy adult persons. Commonly, atypical preprogrammed reactions represent simultaneous activation responses in agonist – antagonist muscle pairs (Horak, and Nashner, 1986). Such responses increase the apparent stiffness of the joint crossed by the muscles and reduce kinematic effects, Latash, Zatsiorsky, 2016

Superfluous internal resistance to movement in dynamic sport is most certainly a factor in the aberrant injury rate as most teams, universities and school athletic, athletic training and physical therapy conditioning programs feature these types exercises, techniques and protocols.  

That being the case, do you really want confine an athlete’s reactiveness to loss or perturbance of equilibrium from running, falling, in the act of being tackled, and so forth; from the hip down?

/ false claims of micro – anatomy;

The statement below recounts two myths; nonetheless, they are widely accepted as fact in therapy rooms, athletic training facilities and so forth:

“The VMO is also a key knee stabilizer. The stronger it is, the more injury proof your joint.”

The idea a single muscle; in this case the vastus medialis oblique (VMO); is a knee stabilizer has no basis in fact. There are many muscles in the lower extremities; including muscles whose attachments cross the knee joint from behind; all of these other muscles are active in running, jumping and other activities typical of dynamic sports. All affect the movement of the knee joint. 

Since when does a joint, knee or otherwise, need to be stabilized? What criterion is applied that makes a joint unstable? The false premise at work here is the knee needs to be stabilized and/or resist movements; irregardless if movements are natural consequences of performing exercises; especially when straining is involved. Furthermore, not only a single muscle; but, the notion the relative strength of this particular VMO muscle; one out 600 plus in the human body will injury proof the knee joint with stability is preposterous. 

Isn’t it curious the importance of the VMO; widely touted in the literature; the focus of training with special isolation exercises in therapy rooms (see figure 5  “Tree Stump Training & Initials” Part I), athletic training facilities, strength and conditioning gyms and so forth, to prevent injury; happens to be same false narrative of another single muscle (transversalis abdominus {TA}? The TA muscle is the centerpiece of so – called core training; and, very much in the same vein as the VMO myth; is likewise another false claim put forth that a single muscle; the TA muscle  can mitigate susceptibility to back injury (see Lederman, E., 2007).

An indication strengthening the VMO with isolation exercises; a practice extensively utilized for decades not only has nothing to do with knee injury; it has failed to mitigate the long standing epidemic of knee ligament injuries; especially among female athletes. In point of fact, a good case could be made ideas such as VMO strength won’t necessarily mitigate susceptibility; but, in all probability be a root cause:

“This injury {ACL tear} is rampant. There are approximately 250 – 300,000 ACL injuries per year in the USA which happen almost exclusively to athletes; however, injury to the MCL ligament of the knee is most prevalent {Phisikul, P., 2006)

“More than 30, 000 serious knee injuries are projected to occur in female intercollegiate and high school athletics in the US each year. The majority of these injuries occur by non-contact mechanisms, most often during landing from a jump or making a lateral pivot while running”. Hewett, T., 2012

“ACL injuries continue to be extremely common in the young athlete population, increasing 2.3% per year, with a current annual incidence of 200,000 injuries. Most of these occur in the high school/college age group;.”US Pharmacist, 2019

/ the problem of kinematic redundancy as a major contributing factor of injury susceptibility;

Academic misrepresentations outside of logic (MOL) bowing of knees in or out during lifting, running, cutting and other motions touted as dangerous to knee, ankle ligaments and tendons is an example of misrepresentation of kinematic redundancy. Kinematic redundancy refers to movement potential in excess of the minimum to accomplish a specific task (Latash, Zatsiorsky, 2016).

Figures 6 & 7. Super elite female weightlifter exhibits kinematic redundancy in the midst of straining to straighten knee hip and ankle joints. Charniga photos  

For instance, the bowing in and out of the legs of the weightlifter depicted in the figures 6&7 would be considered wasted energy. The quadriceps muscles acting to straighten the lower legs would conceivably work more efficiently if the shins were aligned with the feet and thighs. In fact, not only is the inward – outward bowing of the knees considered inefficient it is considered dangerous and a probable cause for ACL (anterior ligament tear). However, such movements are not connected with increased susceptibility to knee injury in weightlifting; especially among female weightlifters.

Consequently, trainers, coaches, therapists and the like who in actuality aid in the precipitation of ACL, ankle and foot injuries; do so, by endeavoring to teach athletes to eliminate kinematic redundancy. The false assumption being, controlling such movements with linear alignments of shin and thigh bones with feet or MOL is safe; while in actuality, it is unsafe.  

That is to say, MOL exercise techniques are designed to restrict movement of joints within boundaries deemed safe without consideration larger than movement amplitudes; are reactive, may not be unsafe, in fact safer; and, potentially more efficient.

So, inculcating restricted motion of joints because of MOL; would conceivably increase the passive resistance of muscles to stretching; especially of the lower extremities, in the event of falling, turning, cutting and so forth; on top of the larger amounts of connective tissue in these muscles which already raise passive resistance to stretching.

Of the many Achilles tendon, ACL knee ligament tears and various ankle injury prophylactic exercises one can find in online videos of experts; few if any feature simple deep knee bends or full squats. Moreover, a simple full flexion knee bend without resistance; or even with an unloaded bar are excluded.

Yet in none of these videos does anyone cite reputable research; or, empirical surveys that purport to show full flexion knee bends cause injury; with figures to back up such claims. For instance, athletes flocking to doctor after incurring injury from this simple exercise. Why would such a simple natural exercise be excluded? Yet, all the make up exercises from the experts somehow can be deemed not only safe; but, injury prophylactic?

/ A Biological versus a chronological window of elasticity

Much is made of the effects of aging on loss of strength and muscles. In fact, a common refrain cited is that of elderly people who are observed to begin bending then fall into a chair; is due an eccentric strength deficit in lower extremities. Something is missing here. Strength most definitely decreases with aging. However, a failure to connect a decline in strength with a likewise concomitant decline in elasticity is common. Falling into a chair could very well be a sign of excessive elastic resistance in bending lower extremities (see section on difference in loss of equilibrium between younger and elderly subjects).

A factor rarely cited, if at all, in academic circles is how loss of elasticity with aging effects muscular strength. The crucial role of elasticity in the youthful body is a principle reason for the rejuvenation of the athlete in strength and power sports. One can make a case good elasticity enhances power output through better utilization of strain energy of tendons, ligaments and fascia. 

Figure 8. Textbook knowledge seldom, if at all, cover the role of elasticity in strength; especially as it pertains to internal resistance to movements as the body ages. Charniga photo. 

Little is to be found in the literature of the connection between loss of muscle – tendon – ligament resilience to the loss of strength with aging. The reason an elderly person has to fall into a chair is probably not due to a lack of strength of the older body; but, the increased resistance to stretching of the aging muscles and tendons. Lower resistance to movement as well as the ability to better utilize strain energy are not part of simplistic academic notions of strength defined in terms of muscle fiber types, hypertrophy and so forth.   

The rising resistance of muscles to passive stretching with age; should be a paramount consideration in training of athletes to mitigate injury susceptibility; as many common techniques and methods of strength and conditioning would tend to hasten the aging process as far as the decline of elasticity of muscles tendons, ligaments and fascia. 

That being said, a distinction between chronological age and Biological age is necessary. For instance, a young athlete in chronological years, with poor mobility from excessive use of static resistance training, restrictive movement of joints in strength training exercises (tree stump training) can in fact be older in Biological years. And, vice versa, an older athlete not compromised by the aforesaid training; can be considered younger than his/her chronological years.        

/ affect of disposition of  the body in strength exercises;

Neuro – muscular activation of muscles vary with body position. Strength exercises performed in different postures do not produce the same improvement in strength; and, as a consequence, can be counterproductive. For instance, strengthening of leg muscles seated will not effectively carry over to the same muscle groups standing; especially from simple machine exercises.

Furthermore, the complexity of the body’s contra-lateral control of the nervous system; where the right side of the brain controls left side of the body and left side of the brain controls the right side of the body; virtually assures simple, low coordination, low equilibrium exercises will not transfer; and more likely hinder complex movements in dynamic sports with a resultant increased susceptibility to injury. 

In fact, one is able to generate more power in complex movements, especially standing, because, among other things, tension on tendons vary; facilitating recoil of elastic energy; conditions which do not exist in simple concentric or isokinetic exercises:    

“…more force may be exerted during complex movements than during isotonic or isokinetic contractions.Bobbert, 1986

Athletes rely on forces greater than what is possible from mere muscle contraction for running, jumping, lifting and so forth, utilizing energy from elastic recoil of the tendon springs; energy systems neither activated nor the coordination structure of which are cultivated with simple strength exercises; especially with machines.


A common denominator across dynamic sports with abnormally high non – contact injury rates of lower extremities is the near universality in the teaching/learning of techniques of strength and conditioning, ‘pre – hab’ and rehabilitation exercises.

The question as to whether these techniques can be a cause of the many injuries in dynamic sports is due in no small part due to an absence of a “consequentialist” (Gree, T. 2022) forethought. That is to say, what are the potential negative consequences of teaching athletes to restrict motion in joints (tree stump training), limit movement of shins in relation to thigh in bending, perform exercises slowly for testing and exercising with resistance machines and so forth: to performance on the athletic field after chronic administration of these techniques? 

A consequentialist approach would necessitate answering the question as to whether the amalgamation of coaches, trainers and therapists involved in athletics could be inculcating internal resistance; or, in effect, raising dynamic resistance to the coordination of  movements, i.e, pre – maturely aging young bodies; which in its turn would make participation in dynamic sport more hazardous.         


/ M.L. Latash, M.L., Zatsiorsky, V. M., Biomechanics of Motor Control, 2016

/ Lederman, E., “The Myth of Core stability”, CPDO Online Journal (2007), June, p1-17. 

/ Charniga, A., “Hamstring injury in sport”,

/ Charniga, A., “Why Safe is Unsafe”,

/ Charniga, A., “Nine straps”,

/ Charniga, A., “Muscles of the Shank, Movement of the Shin & Susceptibility to Lower Extremity Injury”,

/ Charniga, A., “Shouldn’t Female Weightlifters be Injury Prone?”,

/ Charniga, A., “A Stability Instability Convexity”,

/Gudz, P.Z., “Morphological alterations of muscular connective tissue as a result of static and dynamic training”, Papers from the First All – Soviet Conference on Sport Morphology Moscow, The All- Soviet Scientific Research Institute of Physical Culture, 31-33:1975. Translated by Andrew Charniga

/ Latash, M.L., Zatsiorsky, V. M., Biomechanics of Motor Control, 2016

/ Lederman, E., “The Myth of Core stability”, CPDO Online Journal (2007), June, p1-17. 

 / Gree, T. “Pausing at the precipice”,