Reverse Engineering Injury Mechanism and the Consequences of Forward Engineering

Reverse Engineering Injury Mechanism and the Consequences of Forward Engineering

Andrew ‘Bud’ Charniga

Squatting under and receiving a heavy barbell at high speed without negative consequences; disproves the common myth ligaments and joints are susceptible to injury from fast, large range of motion exercises. Charniga photo.

Five previous essays explored the possibility of a concept of reverse engineering as a means to ascertain the etiology of common sport injuries by analyzing circumstances in weightlifting, where one would logically expect an injury to occur; but no injury is manifest. A reverse engineering analysis begins with the ‘why’ someone is not injured under circumstances an injury should certainly occur. Insight from this analysis is applied to determine why serious lower extremity injuries in non – contact running, jumping and so forth, should not only not occur; but should not be commonplace in the USA.

In essence, the logic of reverse engineering injury centers around practical experiences with already known outcomes. Whereas, for want of a better term, ‘forward engineering’ begins and ends with guesses founded on false truisms. A number of these false truisms underpinning forward engineering have been elucidated in previous essays such as:

“The demands placed on the muscles and ligaments of the knee joint during deep squats are severe.. A much safer alternative would be the half squat exercise.” Luttgens, 2002

The hurdlers stretch: “This abnormal stretch places high stresses on the medial structures of the knee joint, which may lead to ligament damage and eventual instability.” Luttgens, Hamilton, 2002

Even though these false truisms and many others of the same vein have appeared in respected Kinesiology books, medical texts, journals and the like, for many years; there is no validity offered and no attempt is made to establish proof of such claims. They point to the hazards created by forward engineering, i.e., predicting injury or susceptibility because of assumptions based on the false belief stretching ligaments or bending a a certain way is dangerous.

Why call the spread of the forward engineering ideas a ‘hazard’? After many years of print, word of mouth, instructional video and so forth, these ideas become so ingrained in the collective conscience, they are not questioned. Or, in the words of Thomas Paine “A long habit of not thinking a thing wrong gives it a superficial appearance of being right”.

These ideas have gained such universal acceptance in the USA that professional teams, university athletics, high schools, elementary schools, fitness magazines, exercise classes are all following the same exercise protocols to restrict knee bends to movement at the hip and knee with minimal movement of the ankle. Furthermore, ankle joints are routinely supported with braces, and/or taped to restrict movement and even feet to shoes beginning already in high school football.

However, the problems created by unsubstantiated forward engineering claims such as stretching ligaments will lead to instability, are incalculable. Enumerable laymen, professional, academic and medical alike, who hear or read of such false ideas; accept them as fact and pass on to others through word of mouth, writings, videos and so forth over a period of many years. Consequently, assuming these ideas are correct the majority never stop to question their veracity. 

For instance, consider the following quote about the avalanche of injuries in the NFL by only week 9 of the 2017 – 2018 season:

“Training methods in the NFL are designed to lower and prevent injuries, including ACL tear prevention,” Tehrany said. 

“I believe that we are looking at a new norm where we need to expect to see and treat more injuries because of the ever-growing strength and speed of the players,” Tehrany said. “Unfortunately, we are seeing this in children as well.” Dr. Armin Tehrany

The lack any semblance of logic with that statement from a medical professional, is in the words of Eldrige Cleaver “part of the problem”, not the solution. Obviously, the doctor cannot conceptualize irrational  training methods can be a significant reason the avalanche of non – contact and even a significant factor in contact injuries in football. Yet, he states without a comment, the same injuries are showing up in children. As the illustrations show children, coaches and athletes at all levels mimic training methods, exercise techniques, taping and other joint supporting activities of the elites in sport.

In point of fact, the excessive injury rate to the lower extremities in the NFL is just the canary in the coal mine for the rest of the athletic community in the USA. Figures 1 and 2 illustrate the expansive effect of some of these false truisms put into practice with children, exercise classes and such.

Figure 1. Children learning to bend at hip and knees minimizing ankles or feet to perform squat exercise. The  false truism on display is that ‘proper’ squatting technique will protect knees by sitting backwards while keeping shin vertical.

Figure 2. Training ligaments and tendons in the manner pictured because “squats hurt knees”.  The truth be known ,there is actually more stress on knees from half bends than bending with knees, hips and ankles as far as possible. Instructions accompanying the photo “…they hurt knees”. “Make sure your knees stay in line with your feet—not wobbling off to one side. And lower your butt only as far as you can without letting your knees bend forward beyond the tips of your toes.”

Sixty Six Joints

It is common knowledge there are 33 joints in each foot, ankle joint inclusive. As the old philosophers would say “nature does nothing in vain”. Consequently, it is nonsensical to assume the human feet with sixty six joints evolved in such a way that all those joints need supportive taping, high top design shoes and/or shoes stiffened to restrict movement. Furthermore, knee bends artificially limiting movement of the shins is a man made solution to some perceived defect in nature’s engineering of the human body.

The three illustrations in figure 3 show how ideas from academia, professional and collegiate sports morph into ‘safe’ exercise techniques. These false truisms spread to high school and collegiate athletics levels where individual interpretations of a bad idea make it worse.

Unfortunately, these examples can only encompass the tip of the tip of the iceberg in terms of the deluge of aberrant ideas which can be found at various levels of the American athletic spectrum; not to mention the spill over from the realms of physical therapy, orthopaedists, personal training, athletic training, and so forth.

“Weightlifting exercises performed with multiple repetitions and with a small amplitude of movement in the joints (and the closer to static tension) causes changes to the muscles’ morphology.” A. Falameyev, 1985


Figure 3. Illustrations of varying degrees of abject stupidity with regards to a fear of bending the ankles to strengthen leg muscles. On the left, a commercial bench is used to perform squats in order to restrict range of motion. In the middle picture a high school football player is propped against a wall with thighs and shins forming a right angle while loaded down with three 30 kg sand bags. The collegiate athlete pictured on the far right is ‘learning’ to squat with face and hands against a wall to prevent shins from moving.

Frequent use of static exercises does not contribute to the development of the habit to relax the muscles. Naturally, prolonged elevation of muscle tonus is one of the reasons for muscle hypertrophy. Elevated “tonic readiness” preceding speed – strength exercises translates into a diminished ability to perform the motor tasks.” Kozlovski, Y.I. Speed – Strength Training of Middle Distance Runners, Kiev, Zdorovaya, 1980

The exercise techniques feature restricted range of motion combined with static conditions which research has shown render a negative influence on performance of dynamic sport exercises. This negative influence includes potential inhibition of the overlooked ability to relax muscles in performing dynamic exercises at high speed. High speed muscle relaxation  is critical to the ability to react to unanticipated circumstances in order to avoid injury.  


Figure 4. World champion female weightlifter deftly drops barbell shaken from her grasp by excessive vibration. The lifter reacted to the falling barbell with rapid  relaxation of the musculature of the lower extremities. This allowed her to push away from the falling weight. The injury avoidance qualities on display are the woman’s rapid of switching from contracting to relaxing muscles and overall suppleness.   Charniga photos.

Little if anything appears in the literature regarding a connection between the ability, or lack thereof, to relax muscles and susceptibility to sport injuries. However, the two quotes above from Soviet era sport scientists, assert employing static tension and exercises with small amplitude of movement to train athletes for dynamic sport is not a good idea.Yet, it is these methods that comprise the preponderance of strength and conditioning methods in the USA for athletes in dynamic sports.

One can anticipate chronic performance of such exercises to lead to an impairment of or a least a diminished ability to relax muscles. The ability to react to unanticipated circumstances in sport by relaxing muscles to dissipate and or otherwise re – distribute mechanical energy cannot be understated. Muscles have to switch from contraction extremely fast in order for athletes to execute changes of direction at high speed. This skill of course comes in handy to avoid injury. Consider the examples in figures 5-7.    

Depicted in figures 5 – 7 are two different circumstances, very similar, but with distinctly different outcomes. The female weightlifter reacts to the falling barbell by first raising her front foot such that her trunk and head moves slightly towards the falling weight. She raises her foot against the combined mass of her body and dropping barbell. The contrasting photo captures of an elite football player who suffers an ACL tear in part because he is unable to raise his planted right foot until this foot is knocked out from under him by an approaching 2nd tackler.

“What we’re finding basically is that when the cleat engages with turf, if it doesn’t release at a certain level of torque, then injury can occur. That’s why we’re seeing so many ankle injuries, ACL injuries.”   R. Anderson, 2013

For instance an explanation of the plethora of lower extremity injuries in football would be: …the “cleats engage with the turf” and don’t release in timely manner. This is not credible. The rules of American football limit the length of the cleats to 12.7 mm, hardly long enough to pin the athlete’s foot to the ground. Furthermore, whole teams would move about the field slower if their cleats could ‘stick’ in the turf so easily.

On the other hand the foot of the female lifter in our example is literally pinned to the floor by the weight of the barbell. Yet her high speed reaction: contraction/relaxation of muscles, makes what looks like a sure injury a non – event.   

Figures 5-7. Two analogous situations of a female weightlifter and elite collegiate football player. The lifter has already reacted to the barbell falling towards her head by raising her firmly planted front foot to push back then push away from the falling barbell to avoid injury. By way of contrast the football player suffers a knee ligament tear after he has been tackled. His front foot is still in mid – air as he is struck in the hip area.

Figures 5 – 7. Examples of enhanced (the female weightlifter) and constrained (the football player) reactive ability to relax muscles to avoid injury (the female weightlifter) and the football player ‘react’ to injury producing circumstances. The elite football player (who suffers ACL injury) keeps his right foot planted over a rather prolonged period of time until it is virtually dislodged by another tackler. By any measure his reaction to dissipate the energy of the contact is so slow to be almost non – existent. By contrast in approximately a similar fraction of a second the female lifter has long since moved away from the falling barbell by rapidly flexing lower extremities.   

Forward engineering from questionable research

“It should also remind us that expert consensus isn’t always correct.” Chrystia Freeland, 2012

An unfortunate circumstance of a bad idea becoming mainstream, even when such ideas as deep knee bends and certain stretches hurt ligaments have been proven false; various transmutations not only persist; but, appear to be backed up by research, i.e., have “a superficial appearance of being right”. 

For instance, several such transmutations from the academic community indicate knee bends are ok as long as the thigh, knee and shin stay in line with the foot (no valgus or varus movement) and the shins should remain relatively vertical (movement of the knee beyond the toes cause a ‘dangerous’ shear). This research fosters false truisms such that exercise protocols are applied and pretty much everyone is bending with thighs, shins and feet in a line; with minimal movement at the ankle joint, and so forth. See the illustrations of children, athletes and exercise classes above.

An example highly questionable research, spawned by the false notion squats hurt knees are the following statements: “… malaligned knee positions may be potentially injurious”; “… inclusion of squats of squats similar to the ballet plie’ squat should be cautioned”. (Slater, L., Hart M., “Muscle Activation Patterns During Different Squat Techniques”, EWF Science Magazine 8:52-65:2017)

The  acceptance and ultimately irrational application en mass of this type of research is a prime example of the menace of forward engineering. On the other hand, reverse engineering is connected to the real world of known outcomes. The inward and outward bowing of the knees is not only common in weightlifting, but, especially so with the female lifter. It is not connected with any injury whatsoever. So, labeling this movement “malaligned” is nonsensical. No research, injury statistics or any practical experience to make such statement are cited in support.

Figure 8-9. Elite female weightlifter shifts knees in and out (varus and valgus movement) straining to lift a heavy weight. The bowing in and out is thought to place an unsafe stress on knee ligaments. Hence the instructions to “Make sure your knees stay in line with your feet—not wobbling off to one side”. This bowing occurs as a result of hip, knee and ankle shifting as on piece, not a deformation of a single joint. This shifting is a reaction to difficult conditions of leverage in order to more effectively overcome the resistance and not some defect. Charniga photos

The same conclusion can be said about this statement”… inclusion of squats similar to the ballet plie’ squat should be cautioned”. No research or statistics are presented or cited of ballet dancers made lame from doing plie’ squats. Furthermore, if the plie’ is dangerous, how in god’s name does one practice ballet without this exercise?

Figure 10. Professional football player suffers such severe knee dislocation upon planting his left foot surgeons were lucky to save his leg. The contact with the opposing player (which cannot be seen from this angle) occurred after the leg broke and was not a factor. Furthermore, note the large disparity in the muscle mass of the player’s upper arm and that of his calf muscle. This is a common occurrence with football players. They develop unnecessary muscle mass in the upper extremities which artificially raises body center of mass; making rapid shifts in direction more difficult.


If everyone is thinking alike, then somebody isn’t thinking”. General George Smith Patton.

Of course it is not possible to conclude with 100% certainty that the ‘safe’ techniques such as bench squats, half squats with vertical ankles, taping and bracing of ankles and knees and so forth are the sole cause of the massive rate of lower extremity injury in American sport. However, the fact remains, the overwhelming majority of all of these injuries in American sport problems have same commonality.

Most everyone in the USA involved in training and treating athletes for dynamic sports follow these protocols. The extraordinarily high rate of lower extremity injury does not occur in the weight room. These injuries become manifest when the athletes for whom the preponderance of conditioning exercises have been  partial range of motion and static movements, switch to dynamic activities: to the football field, soccer field, basketball court, volleyball court,  and so forth.

Static movements such as bodybuilding/powerlifting, machine exercises, limited range of motion exercises deemed ‘safe’ from laboratory measurements are in fact, unsafe over time for athletes whose main endeavor is dynamic sport.

The listing below consists of only some of lower extremity injuries which occur annually in the USA cannot be considered comprehensive due to methods of reporting at various levels of the athletic and medical communities; and, even how an injury is diagnosed. For instance, an injury called a “foot pedal fracture” can be misreported as a Lisfranc because both types which occur in professional football players have been associated with traffic accidents.

Nevertheless, the profoundly negative effect of forward engineering on injury susceptibility is obvious in American athletics; especially, since most everyone training athletes in the USA are employing the same exercise techniques, restricting joint movement, taping and bracing protocols. An opposing argument would be found lacking in credibility; considering the injury statistics presented below:       

Annual Incidence of Some Joint/tendon/ligament injuries in the USA:

Knee ligament related:

  • `”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
  • There are approximately 250 – 300,000 ACL injuries per year in the USA which happen almost exclusively to athletes, Souryal, T.O.
  • “The medial collateral ligament is the most frequently injured ligament of the knee.” {Phisikul, P., 2006)
  • Assuming only a 10% differential between ACL and MCL; that equates to approximately 575 – 630,000 torn or otherwise injured ACL/MCLs in the USA annually;
  • Of just those yearly ACL injuries, at least 140 – 210,000 will require surgery, Souryal, T.O.
  • “Unfortunately, regardless of treatment, athletes with ACL injuries are up to 10 times more likely to develop degenerative arthritis of the knee.“ Labella, C. et al,  Pediatrics, 05/2014:133:5
  • “Joint Replacement To Become The Most Common Elective Surgical Procedure In The Next Decades’,
  • 1,000,000+ joint (knee and hip inclusive) replacement surgeries are performed annually in the USA;
  • The anticipated annual demand of 3.48 million for knee and 572,000 hip replacement surgeries is expected to outstrip the number of available surgeons by 2030,

 Ankle Related injuries in USA and professional football

  • An ankle injury is the most common injury in American athletics, by some estimates 45% of all sport injuries are related to the ankle, Kaminski, T., 2013;
  • Approximately 230,000 Achilles tendon injuries occur annually in the USA; the rate is rising,;
  • An annual rate of 4 – 10 Achilles tendon ruptures in the NFL has become common.

Foot Injuries

  • Back in the 2000s, we saw a tremendous rise in foot and ankle injuries in the NFL and we were trying to figure out why this was happening.” Anderson, R.B,
  • “The rate of Lisfranc fractures have been rising in the NFL: Such diagnoses were rare in the 1990s, but from 2000–05, the NFL saw an average of 14.2 per season, which increased to 18.9 from 2006–14”, Lareau, C.R., Hsu, A.R., Anderson, R.B,
  • “Jones fractures commonly occur in professional athletes and operative treatment remains the standard of care in this patient population.” Lareau, C.R., Hsu, A.R., Anderson, R.B,
  • There is no precise data on the number of plantar fascia ruptures and fascitis injuries in the NFL; however, anecdotal evidence suggests the affliction is becoming more common.

In Contrast to the Problems Caused by Forward Engineering 

  • Stress on the Achilles tendon, the foot and the ankle joint in Olympic Weightlifting exercises are arguably among the highest in all of sport;
  • Ankle and foot injuries, especially Achilles tendon ruptures are virtually unheard of in weightlifting .
  • The loading on the lower extremities in the weightlifting exercises is extraordinarily high; yet the overall injury rate is low.

What is the upshot of all of this? Like some contagious disease a single bad idea can morph into various forms and magnify over time with terrible consequences. Non – contact, and, even many contact injuries to the lower extremities of NFL players should be viewed from the standpoint of the ‘canary in the coal mine’. Why? Because tens of thousands of young athletes coaches and so forth, follow the same irrational training methods as the elites in sport; and, like some out of control contagious disease, still many more copy them. Anecdotal proof positive of this is the doctor’s observation “Unfortunately, we are seeing this in children as well.” Dr. Armin Tehrany. 


 1/ Dept. of Othropedic Surgery UCSF, “Anterior Cruciate Ligament Injury (ACL) Overview”

2/ Souryal, T.O., “ACL Injury, ACL Tear, ACL Surgery”,, 2015

3/ Treatment Guide: ACL Injuries,

4/ Mayo Clinic Overview: ACL Injury,

5/ Hewett, T., “Neuromuscular and Hormonal Factors Associatyed with Knee Injuries in Female Athletes”, Sports medicine 29:52000:313-327; 2012

6/ American Academy of Orthopaedic Surgeons, “Total Knee and Hip Replacement Surgery Projections Show Meteoric Rise by 2030”

7/ Fox, M., “Knee Patients Spending Millions on Wasted Treatments”,

8/ David Ruiz, Jr., MA1; Lane Koenig, PhD1; Timothy M. Dall, MS2; Paul Gallo, BS2; Alexa Narzikul, BA3; Javad Parvizi, MD3; John Tongue, MD, “The Direct and Indirect Costs to Society of Treatment for End-Stage Knee Osteoarthritis”, The Journal of Bone & Joint Surgery, Volume 95, Issue 16

9/ Zajac, F.E., “Muscle Coordination of Movement: A Perspective”, J. Biomechanics 26:suppl1:109-124:1993

10/ “Achilles Tendon Injury On the Rise”,

11/ “Joint replacement is becoming more common. More than 1 million Americans have a hip or knee replaced each year.


13/ Phisitkul, P. et al, “MCL Injuries of the Knee: Current Concepts Review”, Iowa Orthop J, 2006:26:77-90

14/ Miyamoto, RG, et al, “Treatment of medial Collateral Ligament Injuries”, J Am Acad Orthop Surg. 17(3:152-61:2009

15/ Charniga, A., “It is all connected” I-III;

16/ Charniga, A., “Achilles tendon ruptures and the NFL”, Practical solutions to the problem of Achilles tendon rupture and the proliferationof injurois to the lower extremities of football players,

17/ Charniga, A., “There is no system” I-VI;

18/ Kaminski, T., et al, “National Athletic Trainers Association Position Statement: Conservative Management and Prevention of Ankle Sprains in Athletes”, J. of Athletic Training, 48(4):528-545:2013

19/ Lareau, C.R., Hsu, A.R., Anderson, R.B, “Return to play in national football league players after operative Jones fracture treatment”,

20/, “NFL Injury bug continues to spread league – wide”,

21/ Hunt, K., et al, “High Ankle Sprains and Syndesmotic Injuries in Athletes”, Journal of the American Academy of Orthopaedic Surgeons, 23:11;661-673:2015 Wei et al15 demonstrated the influence of shoes with flexible uppers on talus motion. These shoes allow greater talar eversion and transfer more stress to the AITFL. Thus, the level of shoe constraint may also contribute to syndesmotic injury

22/ Paine, T., Common Sense, 1776

23/ Slater, L., Hart M., “Muscle Activation Patterns During Different Squat Techniques”, EWF Science Magazine 8:52-65:2017


25/ Cerrato, R., “Lisfranc Injuries”,

26/ Hsu, A., Anderson, R.B., “Foot and Ankle Injuries in American Football”, Am J Orthop. 2016 September;45(6):358-367

27/ Souryal, T.O., “ACL Injury, ACL Tear, ACL Surgery”,, 2015



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