Archive for the ‘Safety Studies’ Category

A study was recently published in the British Journal of Sports Medicine reviewing the Amateur International Boxing Association’s recent rule change to remove headgear from international competition.

In the recent study (Because Not All Blows To the Head are the Same) the authors suggest that one type of impact, namely head clashes, can lead to serious injury and headgear is effective in reducing these risks.

The study reviews a specific case involving  22 year old boxer who suffered an acute subdural haematoma following an international bout where he received multiple head to head impacts.

The study notes that while the number of direct punches to the head are relatively similar with and without headgear, head to head impacts rose more than 40% with no headgear.

The study suggests that the risk of injury from head clashes is a reason to revisit the issue of whether headgear should be worn in amateur boxing.

A journal subscription is needed to access the full article but an extract is available here.

As recently discussed, one of the most important questions in combat sports medicine is how much head trauma is too much?

Although the answer is not known, the current regulatory landscape could use improvement in deciding when regulators should pull the plug on an athlete that is ‘too tough for their own good‘.  To this end an important study was published today in the Journal of The Physician and Sports Medicine addressing this issue and calling for regulatory consistency.

In today’s article titled Determining Brain Fitness to Fight: Has the Time Come? the authors highlight the fact that “up to 20-50% of former professional boxers” exhibit symptoms of  chronic brain injury.  They further note that “the precise threshold of damage required for the production of both acute and chronic neuropathology remains elusive; thus early detection and appropriate management of neurological injury in professional boxing is imperative“.

The note that without central regulation “there is little uniformity with regard to the medical regulation of professional boxing in the United States” with some commissions understanding the perils of head trauma far less than others.  The authors call for a uniform set of minimum requirements for brain safety that would be available and shared between states.  The recommended standards include –

  • Standardized neurological testing
  • Use of Neuroimaging
  • Adoption of a Fight Exposure Index to identify High Risk Fighters
  • To consider looking to biomarkers in future years if their clinical significance becomes clearer

The article ends with the following conclusion –

Unfortunately, acute and chronic brain injuries are the most common injuries sustained by boxers. The sport has long been regulated by state commissions, but currently these governing bodies vary greatly in providing for the neurologic health of boxers. Many states lack best practice medical requirements and enforcement varies widely, which leads to forum shopping by the boxer until a favorable fighting venue is located. State regulation of boxing also results in conflicts of interest because stringent regulation by a state may lead to lost revenues when a bout is scheduled elsewhere. Boxing remains the only major sport in this country that lacks a central regulatory organization. Concussion and lasting brain damage is an especially significant risk for boxers, as the goal of the sport is, in fact, to deliver a concussion to the opponent. With studies estimating that up to half of all boxers will suffer from chronic traumatic brain injuries, the time has come for the development of uniform minimum requirements for brain safety that all states incorporate. The health of boxers and the long-term viability of the sport both depend on it.

Update – August 18, 2015 – another useful discussion was recently published in the text “Brain Neurotrauma” confirming that more insight into CTE is needed with the authors noting “Despite extensive publicity, the real risk of CTE among amateur and professional players has not been measured or adequately characterized and notions derived from autopsy studies, although useful for understanding mechanisms, cannot give an accurate picture of the range of outcomes after repeat concussions and are limited because of ascertainment bias

_____________________________________

As recently discussed, science does not have a clear understanding of how many hits are too many when it comes to a career in combative sports.  What is known, however, is that an accumulation of trauma, both concussive and sub-concussive, play a role in the development of CTE.

A study was recently published in the Journal of Current Pain and Headache Reports titled “Concussion in Chronic Traumatic Encephalopathy” confirming this understanding.

The authors note that “Overall, the number of years of exposure, not the number of concussions, was significantly associated with worse tau pathology in CTE. This suggests that it is the chronic and repetitive nature of head trauma, irrespective of concussive symptoms, that is the most important driver of disease.”

The study’s Abstract, which can be found here (I can’t republish the full study yet as it is behind a paywall) notes:

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease that occurs in association with repetitive mild traumatic brain injury. It is associated with a variety of clinical symptoms in multiple domains, and there is a distinct pattern of pathological changes. The abnormal tau pathology in CTE occurs uniquely in those regions of the brain that are likely most susceptible to stress concentration during trauma. CTE has been associated with a variety of types of repetitive head trauma, most frequently contact sports. In cases published to date, the mean length of exposure to repetitive head trauma was 15.4 years. The clinical symptoms of the disease began after a mean latency of 14.5 years with a mean age of death of 59.3 years. Most subjects had a reported history of concussions with a mean of 20.3. However, 16 % of published CTE subjects did not have a history of concussion suggesting that subconcussive hits are sufficient to lead to the development of CTE. Overall, the number of years of exposure, not the number of concussions, was significantly associated with worse tau pathology in CTE. This suggests that it is the chronic and repetitive nature of head trauma, irrespective of concussive symptoms, that is the most important driver of disease. CTE and exposure to repetitive head trauma is also associated with a variety of other neurodegenerations, including Alzheimer disease. In fact, amyloid β peptide deposition is altered and accelerated in CTE and is associated with worse disease. Here, we review the current exposure, clinical, and pathological associations of CTE.

Getting hit in the head is not good.  How much head trauma is too much?   As the executive director of the Sports Legacy Institute tells us, nobody really knows but the connection to CTE is clearly there

Tweet RE CTE and Trauma

What is known, however, is that trauma is cumulative and there is only so much mileage an athlete can be exposed to before the toll adds up.  A recent study was published earlier this year in the International Journal of Basic Sciences and Applied Research shedding more light on this issue in the context of boxing.

The full study, titled Comparison of Neuropsycholgical Disorders of Professional and Amateur Boxers can be found here.

The study participants were 20 amateur boxers with at least two years of Iranian National Team membership experience, 20 amateur boxers with no national team membership experience and 40 non-athletes.  The participants were put through a battery of neuropsychological tests.

The results, not surprisingly, were that “boxing develops more serious neuropsychological implications in people who compete professionally and in national level than those with no national team membership background”.

The measured neurospychological deficits included impairment of visual memory, intelligence quotient visual perception and fundamental visual abilities.

Studies like this confirm that all combat sport athletes must appreciate that the tolls of brain trauma are cumulative and care must be taken to minimize the volume of trauma exposure over the course of a career.  The dangers inherent in the sport cannot be eliminated but athletes who engage in practices such as ‘hard sparring’ are playing Russian roulette increasing the odds of taking that immeasurable ‘one shot too many’.

Adding to this site’s archives canvassing safety studies in combat sports, two studies were published this month in the British Journal of Sports Medicine.  The first addressed injury rates in elite level amateur boxing.  The second addressed the impact performance of various headgear.

The first study titled “Boxing Injury Epidemiology in the Great Britain Team” reviewed injuries in training and competition in the Great Britain (GB) amateur boxing squad between 2005 and 2009.  The studies highlights were as follows –

  • Total injury rate during competition was 828 injuries per one thousand hours of competition
  • More injuries occurred during training than during competition
  • More injuries affected the hand than any other body location
  • Hand injury rate in competition was 302 injuries per 1000 hours
  • The incidence of recorded concussions was “comparatively low

An abstract of the article can be found here.

The second study, titled “The Impact Performance of Headguards for Combat Sports” aimed to assess the impact energy attenuation performance of a range of headguards for combat sports.

Seven different headguards of varying thickness were  put through a drop test with a 5.6 kg drop assembly mass. Tests were conducted against a “flat rigid anvil” both with and without a boxing glove section.

The results of the study were as follows –

Headguard performance varied by test condition. For the 0.4 m rigid anvil tests, the best model headguard was the thickest producing an average peak headform acceleration over 5 tests of 48 g compared with 456 g for the worst model. The mean peak acceleration for the 0.4, 0.5 and 0.6 frontal and lateral rigid anvil impact tests was between 32% and 40% lower for the Top Ten boxing model compared with the Adidas boxing model. The headguard performance deterioration observed with repeat impact against the flat anvil was reduced for impacts against the glove section. The overall reduction in acceleration for the combination of glove and headguard in comparison to the headguard condition was in the range of 72–93% for 0.6 and 0.8 m drop tests.

An abstract of the study can be found here.

Adding to this site’s archived posts addressing safety studies in combative sports, an importation study was published in the Annals of Neurology this month finding that traumatic brain injury likely causes accelerated atrophy “aging” the brain by an average of over four years.

In the recent study conducted by James H. Cole, PhD, Robert Leech, PhD, and David J. Sharp, PhD, the researchers were able to accurately predict brain age based on MRI data.  The same brain age calculating methods were then applied to MRI’s from patients who suffered traumatic brain injuries.  The data set included 99 patients with persistent neurological problems after suffering a traumatic brain injury.  The cause of injury included a variety of mechanisms including sports injuries, vehicle collisions, assaults among others.

The study found, regardless of the cause of injury, the patients who suffered a traumatic brain injury had accelerated brain atrophy making their brains appear 4.66 years older than their actual age.  The severity of brain injury correlated to the severity of ‘aging’ with more profound brain injuries leading to greater brain atrophy.

Figure 1 TBI Aging StudyFigure 4 TBI Aging Study

The full study is valuable for anyone interested in health and safety issues in combat sports and can be found here – Prediction of Brain Age Suggests Accelerated Atrophy after TBI

Rapid Extreme Weight Cuts have taken their toll on the health of many combat sport practitioners and may even play a role in fatalities in combat sports such as boxing and MMA.

Regulators and others involved in the industry have slowly started to take notice with calls for reform with perhaps the most viable suggestion being that athletes be required to pass a hydration test when making weight.

A new study has now been published in the International Journal of Sport Nutrition and Exercise Metabolism documenting more harms of the practice.  The study reviews biochemical and hormonal responses between MMA practitioners who undertake rapid cuts versus those that do not.  In short the study concludes “The practice of rapid weight loss showed a negative impact on energy availability and increased both muscle damage markers and catabolic expression in MMA fighters.”

An abstract of the recent study,titled Rapid Weight Loss Elicits Harmful Biochemical and Hormonal Responses in Mixed Martial Arts Athletes, can be found here.

Adding to this site’s archives of combat sports safety studies, important findings were published today connecting reduced brain volume and slower processing speed to the number of years and the number of bouts combat sports athletes endure.

In today’s study (Repeated head trauma is associated with smaller thalamic volumes and slower processing speed) published at the British Journal of Sports Medicine, 224 fighters (131 mixed martial arts fighters and 93 boxers) were recruited along with 22 controls.  Each participant underwent computerised cognitive testing and volumetric brain MRI.  The results were that “Increasing exposure to repetitive head trauma measured by number of professional fights, years of fighting, or a Fight Exposure Score (FES) was associated with lower brain volumes, particularly the thalamus and caudate. In addition, speed of processing decreased with decreased thalamic volumes and with increasing fight exposure

The study concluded that “Greater exposure to repetitive head trauma is associated with lower brain volumes and lower processing speed in active professional fighters.“.

Perhaps not surprisingly, boxers were found to have endured more damage as illustrated by the following graphic:

Reduction of Brain Volume in Boxers v MMA Fighters

The study will follow up with its participants for baseline evaluation on an annual basis over the next 4 years. Given the longitudinal nature of this study important information is expected to be forthcoming in the following years giving far greater insight into the toll of combat sports on the brain.

In my ongoing efforts to highlight studies addressing safety issues in combat sports, an interesting study was recently published by Benjamin Lee and Stuart McGill from the Spine Biomechanics Laboratory, at the University of Waterloo (Canada) testing the peak forces caused by MMA gloves contrasted with 16 oz boxing gloves.  The study also reviewed the time to peak force between these gloves along with their patterns of wear during 10,000 strikes.

The study reached the following conclusions:

MMA  gloves  produced  4‐5  times  greater peak force and 5 times faster load rate compared to the boxing glove. However, MMA gloves also showed signs of material fatigue, with peak  force increasing by 35% and rate of loading increasing by 60% over  the duration of  the  test. Boxing glove  characteristics  did  deteriorate  but  to  a  lesser  extent.  In  summary,  the  kinetic  properties  of  MMA  glove  differed substantially from the boxing glove resulting in impacts characterized by higher peak forces and more rapid development of  force. Material properties including stiffness and  thickness play a role in  the kinetic characteristics upon impact, and can be inferred to alter injury mechanisms of blunt force trauma. 

The full study can be found here: Striking dynamics and kinetic properties of boxing and MMA gloves

I asked physicist Jason Thalken, a person who knows a thing or two about the science of striking, for some feedback on the importance of this data who felt that the peak force metric was not nearly as important as the faster time to peak force produced by MMA gloves.  Here are Jason’s comments:

Jason Thalken 1

JAson Thalken 2

As a long time fan of MMA and other combat sports I feel past, current and future athletes are owed a fair and sober discussion of the realities of traumatic brain injury.  Yes a bit of common sense tells us these sports have inherent dangers and yes being hit in the head is not good for ones health.  That said, the legacy of traumatic brain injury usually builds slowly over time and can be a near invisible problem that deserves its ever increasing attention.

To this end I recently came across a video and medical case study from storied MMA veteran Guy Mezger who has been left with a legacy of traumatic brain injury after ‘17 years of being hit in the head.’

Here is Guy’s story along with a case study detailing his symptoms.  I’m not sharing this to bash the sport, simply pointing out an ugly byproduct that can come with a career in MMA.

Guy presented with:

  • daily bouts of severe dizziness
  • was not able to perform normal daily activities due to lack of balance
  • difficulty tracking written word
  • difficulty walking
  • daily mental fatigue
  • memory loss
  • Profound reduction in his balance on a normal surface, even with his eyes open.
  • Severe reduction in balance on a flat surface, with eyes closed.
  • Profound reduction in balance on an unstable surface with eyes open.
  • Profound reduction in balance on an unstable (foam) surface with eyes open.

The below video is an advertisement detailing some treatments Mezger took which fortunately appear to have lessened some of his symptoms.  Despite the commercial nature of the below video the points made about having an exit strategy and the focus on brain health are worth highlighting for those involved in combat sports.

On a related note, former MMA fighter and boxer Michele “Diablita” Gutierrez recently shared the long term effects she has suffered from combat sports which can be found here.