Archive for the ‘Safety Studies’ Category

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.

Recently the Journal of Athletic Enhancement released a first of its kind study examining the cognitive performance on neuropsychological testing of MMA athletes.

The study, authored by Christopher Heath and Jennifer Callahan, conducted a series of cognitive performance tests on 28 MMA athletes and a control group of 28 non MMA athletes.

The MMA athletes “reported training an average of 2.6 days per week”.   The participants sparred “approximately 109 minutes each week“. 29% of these participants reported previously experiencing a knockout with almost half of the group reporting a previous TKO.  The mean age for the athletes was 28.9 years.

The control athletes were non MMA fighters who “participate in exercise regimens that do not involve repeated head trauma” such as submission wrestling or high intensity interval training.

The study sought to see if the MMA athletes would differ in neuropsycholigical functioning compared to the control group.  No meaningful differences were found with the authors concluding that “the neurocognitive performance of MMA athletes was indistinguishable from control athletes not regularly exposed to repeated head trauma“.

The risk of head trauma in MMA, as with any full contact sport, remains real and studies such as this should not be misinterpreted to suggest that MMA is not without real risks.  The study points out its limitations noting that additional research is warranted particularly focusing on a larger sample and breaking down further factors such as intensity and frequency of sparring.  That said, the study’s conclusion that “participation in the growing sport of MMA by a typical athlete may not pose significant – or at least unique – neuropsychological risk” compared to other contact sports is worth noting by stakeholders studying these issues.

Findings such as this must be tempered by other studies such as the Cleveland Clinic’s ongoing longitudinal “Professional Fighters Brain Health Study” which has released the following initial findings:

  • Across an average of all data collected, there is a relationship between number of fights and decline in the volume of certain areas of the brain
  • Changes in brain volume are not seen until after approximately five years of professional fighting and not all fighters exhibit such changes
  • The number of professional fights and knock outs are correlated with loss of fibers that course across the brain, as well as the connectivity between different areas of the brain as seen on MRI brain imaging. The implications of these findings are currently unknown; only long-term follow-up will determine if they predict neurological decline.

The full article can be found here – Assessment of Cognitive Functioning in Mixed Martial Arts Athletes

Following UFC 177, an event which had headliner Renan Barao yanked from his title bout following a difficult weight cut, UFC President Dana White was asked whether this is a sign that the UFC can or should do anything to get involved in this process” referring to rapid extreme weight loss (“REWL”) practices which are the norm in MMA, to which White responded “Nobody’s ever been hurt from it, I mean, there’s only so much we can do“.

This reminds me of Senator Moynihan’s famous quoteEveryone is entitled to his own opinion, but not to his own facts.”

The truth is athletes have been hurt as a result of rapid extreme weight cutting practices.  A few examples include –

Renan Barao is the latest addition to this list.  I have shared this list on mixedmartialarts.com where Dr. Rahjai added the following helpful comments:

…weight cutting is very difficult on the body as you are messing around with electrolytes and fluid balances which are against the natural homeostasis of the body.
Low Calcium, magnesium, and especially potassium can result in cardiac conduction abnormalities which can potentially lead to cardiac arrest if severe enough.  Also the strain it puts on the kidneys is tremendous.   That’s just the more likely causes of death not listing the other potential causes!  Dangerous comment to make suggesting it’s normal for people to lose 20+ lbs at a time

Despite Dana’s quote,in reality the UFC is well aware that harm does come from REWL practices.   For proof you simply need to fast forward a mere twenty minutes in time from the post event press conference to the subsequent media scrum.  Here White acknowledges the harm suffered by Barao noting as follows “When they come in we weigh all of them so we have a good idea where everybody is and know where they are.  What happened this time, and don’t quote me on this…is he got to (138 pounds) and that was it, his body shut down and wasn’t cutting any more weight…He was 138 when he feinted and it wasn’t even a feint, what happened is once you deplete all the electrolytes in your body you basically become paralyzed.  That’s what happens.  You become paralyzed and you can’t move any of your limbs.  They had to come and call 911.

White goes on to suggest that athletes alone have the responsibility to make weight.  While it is true that professional athletes do bear responsibility for their actions promoters cannot turn a blind eye to dangerous practices that take place under their nose.  The UFC knows exactly how much their fighters weigh when they arrive at their fight location the week prior to a bout.  In turn this means the UFC knows exactly how much weight their athletes are going to attempt to lose and as illustrated by the above examples these cuts are not always made safely.

Just as the NCAA fashioned safety measures following deaths from REWL practices in the 1990’s, promotions such as the UFC along with State and Provincial Athletic Commissions can fashion minimum safety measures to prevent further tragedies from occurring in MMA.  At a minimum, adding a hydration requirement when athletes make weight can go a long way in addressing dangerous cuts.  Whatever the solution, ignoring the problem and saying “nobody’s ever been hurt from it” is not the answer.

Although the mandatory use of gloves in Mixed Martial Arts was one step which helped bring the sport from its ‘human-cockfighting‘ stigma into greater mainstream acceptance, this requirement likely increased the incidence of brain trauma for the sport’s participants.

Gloves protect fighters’ fists from injuries and reduce superficial cuts to opponents but do little to protect an opponent from brain injury.  Given the greater understanding of the long term harm that accompanies head trauma, I decided to look at objective evidence of the greater rate of knockouts from punches in MMA with the addition of gloves.  In short, the knockout rate from punches increased from 1% to 10% after gloves became mandatory for the sport.  While I appreciate that correlation does not always prove causation this is, at the very least, a compelling statistic.

Methodology –

I reviewed the results from the numbered UFC events from UFC 1 to UFC 50.  Where only a KO was noted with no accompanying information as to the cause of the KO, I reviewed the bouts to determine if the KO was from punches or other strikes.  In the early tournament format UFC’s I excluded any alternate bouts as video footage was not readily accessible to review any ambiguously reported knockouts.  TKO stoppages were not included in this study.

Results –

Gloves became a required part of the sport at UFC 14.  For this reason the study broke these events down into two categories, the events from 1-13, and 14-50.  In the first 13 events a total of 101 bouts occurred.  Of these only 4 knockouts by punches were noted.  However, 3 of these occurred with the winner wearing gloves.  The only bout with a knockout stoppage noted from punches with the winner not wearing gloves occurred at UFC 3 with Harold Howard defeating Roland Payne with a KO at the 0:46 mark.

This leaves a margin of one glove-less knockout via punches out of 98 bouts, a frequency of about 1%.

Moving on to UFC 14 – UFC 50 the data reveals a total of 279 bouts.  Of these 27 ended via knockout noted by punches.  This is a total of approximately 10%, a tenfold increase in the rate of KO by punches.

Removing gloves from MMA will increase the rate of fractured hands and superficial lacerations to competitors.  “Bare knuckle” fighting is also likely to be met with resistance by government regulators so the likelihood of the removal of gloves from the sport is slim.  That said, the above shows that the removal of gloves from the sport can reduce head trauma.  If government and MMA stakeholders review the rules of the sport with brain injury in mind the data is fairly clear that gloves protect the hands, not the brain.

Adding to this site’s archived medical literature addressing safety issues in combat sports, an important study was published this week in the Journal of the American Medical Association addressing objective brain changes in college football players.

The study compared three groups:

1. College football players with no concussion history

2. College football players with a concussion history

3.  A control group of non football players

The study found that the football players with no concussion history had smaller hippocampal volumes than the control group and the players with a concussion history had an even more reduced volume.

Perhaps more importantly the study showed that “there was a statistically significant inverse relationship between left hippocampal volume and number of years of football played“.  In other words, the more years playing football, the greater changes in the brain.

This study adds to the literature strongly suggesting that repeated sub concussive hits (ie – checking in hockey, contact in football and striking in combat sports) do take their toll over time.

As previously discussed, the relevant lesson from studies such as these is that there is a shelf life for combat sports participation and further that hard sparring takes its toll.  The brain can only take a finite number of jostles before negative repercussions take place.  Combat athletes would do well to not only be aware of this but to spar smart and not expose themselves to unneeded damage while training.

Below is the full abstract of the recent study.

_________________________________________________________________

Importance  Concussion and subconcussive impacts have been associated with short-term disrupted cognitive performance in collegiate athletes, but there are limited data on their long-term neuroanatomic and cognitive consequences.

Objective  To assess the relationships of concussion history and years of football experience with hippocampal volume and cognitive performance in collegiate football athletes.

Design, Setting, and Participants  Cross-sectional study conducted between June 2011 and August 2013 at a US psychiatric research institute specializing in neuroimaging among collegiate football players with a history of clinician-diagnosed concussion (n = 25), collegiate football players without a history of concussion (n = 25), and non–football-playing, age-, sex-, and education-matched healthy controls (n = 25).

Exposures  History of clinician-diagnosed concussion and years of football experience.

Main Outcomes and Measures  High-resolution anatomical magnetic resonance imaging was used to quantify brain volumes. Baseline scores on a computerized concussion-related cognitive battery were used for cognitive assessment in athletes.

Results  Players with and without a history of concussion had smaller hippocampal volumes relative to healthy control participants (with concussion: t48 = 7.58; P < .001; mean difference, 1788 μL; 95% CI, 1317-2258 μL; without concussion: t48 = 4.35; P < .001, mean difference, 1027 μL; 95% CI, 556-1498 μL). Players with a history of concussion had smaller hippocampal volumes than players without concussion (t48 = 3.15; P < .001; mean difference, 761 μL; 95% CI, 280-1242 μL). In both athlete groups, there was a statistically significant inverse relationship between left hippocampal volume and number of years of football played (t46 = −3.62; P < .001; coefficient = −43.54; 95% CI, −67.66 to −19.41). Behavioral testing demonstrated no differences between athletes with and without a concussion history on 5 cognitive measures but did show an inverse correlation between years of playing football and reaction time (ρ42 = −0.43; 95% CI, −0.46 to −0.40; P = .005).

Conclusions and Relevance  Among a group of collegiate football athletes, there was a significant inverse relationship of concussion and years of football played with hippocampal volume. Years of football experience also correlated with slower reaction time. Further research is needed to determine the temporal relationships of these findings.