Archive for the ‘Safety Studies’ Category

CTE is a part of combat sports.  In fact the disease, which used to be called dementia pugilistica (ie “punch drunk”) has its origins traced back to boxing.

MMA is not immune from CTE.  It is a real risk. Several athletes likely have the disease with fighters such as Gary Goodridge being diagnosed with CTE and being vocal about its realities.  Despite the high likelihood that many MMA athletes have CTE it is a diagnosis that cannot be made definitively until death as study of brain tissue is required.

Now, the Boston Globe Reports, MMA has its first proven case of CTE.

Former Bellator fighter, Jordan Parsons, who was recently killed in a pedestrian/vehicle collision, has been diagnosed with CTE post-mortem.

The Globe reports as follows:

Now, six months after he was struck and killed as a pedestrian by an alleged drunken driver, Parsons is the first fighter in the multibillion-dollar MMA industry to be publicly identified as having been diagnosed with the degenerative brain disease known as chronic traumatic encephalopathy (CTE)

The diagnosis was disclosed to the Globe by Dr. Bennet Omalu, a forensic pathologist who first discovered CTE in a professional football player (in 2003) and a professional wrestler (2007).

Omalu provides the following grounded and sober comments “As a scientist, a physician, and a person of faith, I beg everybody involved with these sports to come together and identify the problems and find solutions’’

Combat Sports athletes should participate only with informed consent of the sport’s real dangers.  Comments calling MMA “the safest sport in the world” do no favors.  Informed consent only comes from an acknowledgement and understanding of the science of CTE and its links to acute and repetitive head trauma.

Regulators also must grapple with this reality both in making informed choices as to when an athlete has been exposed to too much mileage and when considering safety issues such as the fact that gloves, while making for more exciting fights, do much to increase the likelihood of brain trauma.

Adding to this site’s archived combat sports safety studies and weight cut reform articles, a study was recently published in the International Journal of Sport Nutrition and Exercise Metabolism  finding all MMA athlete participants being dehydrated when weighing in for competition with the magnitude of rapid weight loss and strategies being “comparable to those which have previously resulted in fatalities“.

In the study, titled Extreme Rapid Weight Loss and Rapid Weight Gain Observed in UK Mixed Martial Arts Athletes Preparing for Competition, the authors measured dietary intake, urinary hydration status, and body mass of several MMA athletes in the week prior to competition.  Despite the small sample size the authors observed troubling findings that “”At the official weigh-in 57% of athletes were dehydrated… and the remaining 43% were severely dehydrated

The authors call for “Rule changes which make RWL impractical should be implemented with immediate effect to ensure the health, safety and wellbeing of competitors.”  Given the ever growing Rapid Weight Loss Injury/Fatality List in MMA this is a sensible call to action.

Below is the study’s full abstract:

There is a lack of research documenting the weight-making practices of mixed-martial-arts (MMA) competitors. The purpose of the investigation was to quantify the magnitude and identify the methods of rapid weight loss (RWL) and rapid weight gain (RWG) in MMA athletes preparing for competition. Seven athletes (mean ± SD, age 24.6 ± 3.5 yrs, body mass 69.9 ± 5.7 kg, competitive experience 3.1 ± 2.2 yrs) participated in a repeated-measures design. Measures of dietary intake, urinary hydration status, and body mass were recorded in the week preceding competition. Body mass decreased significantly (p<0.0005) from baseline by 5.6 ± 1.4 kg (8 ± 1.8%). During the RWG period (32 ± 1 hours) body mass increased significantly (p<0.001) by 7.4 ± 2.8 kg (11.7 ± 4.7%), exceeding RWL. Mean energy and carbohydrate intake were 3176 ± 482 kcal·day−1and 471 ± 124 g·day−1, respectively. At the official weigh-in 57% of athletes were dehydrated (1033 ± 19 mOsmol·kg−1) and the remaining 43% were severely dehydrated (1267 ± 47 mOsmol·kg−1). Athletes reported using harmful dehydration-based RWL strategies, including sauna (43%) and training in plastic suits (43%). Results demonstrated RWG greater than RWL, this is a novel finding and may be attributable to the 32 hour duration from weigh-in till competition. The observed magnitude of RWL and strategies used are comparable to those which have previously resulted in fatalities. Rule changes which make RWL impractical should be implemented with immediate effect to ensure the health, safety and wellbeing of competitors.

Adding to this site’s archives of safety studies in combat sports, a recent article was published in the Journal of Neurology and Neurorehabilitation Research further noting the connection between neurological system impairment and the frequency and severity of subconcussive head impacts.

In the article, titled “PROTECT THE PLAYER, PROTECT THE GAME: SUBCONCUSSION AND CHRONIC TRAUMATIC ENCEPHALOPATHY”  the authors note the following findings consistent with other research indicating that mileage matters when it comes to sports related brain trauma:

Our recent clinical studies suggest that some of neurological system may be impaired and reflective of frequency and magnitude of subconcussive head impact sustained. For example, 10 bouts of soccer headers with an average magnitude of 14.5 g led to a transient dysfunction in vestibular processing, causing significantly larger postural sway while static and walking (Hwang, 2016). Similarly, soccer headings acutely blunted the ocular-motor system, particularly near point of convergence, and the impairment persisted even after 24 hours of resting (Kawata, 2016), pointing to the possibility that vulnerability and slow recovery nature of the ocularmotor system. A follow-up prospective longitudinal study in collegiate football players confirmed our finding that the degree of impairment in the ocular-motor function was dependent on the frequency and magnitude of subconcussive head impact sustained (Kawata, 2016). Taken together, although a direct causality between subconcussive head impact exposure and development of CTE remains elusive, it is imperative to employ prospective cohort approaches, rather than case-reports, as to delineate chronic effects of head impact and different factors (e.g. age, gender, genetics) contributing to the disease.

Mild traumatic brain injury is sometimes referred to as an ‘invisible injury’ as there is often no objective evidence to help diagnose the damage done. Instead a diagnosis is made based on a host of subjective complaints.  Repetitive concussive and sub-concussive blows are linked to CTE.  This disease also cannot be diagnosed with certainty in living individuals and objective criteria demonstrating risk of this disease are lacking.

An interesting study was published in JAMA Neurology this month, however, showing promise that certain biomarkers may be “an objective tool to assess the degree of central nervous system injury in individuals with PCS (post concussion syndrome)” and further that this tool may even be used to screen athletes that are at high risk of developing CTE.

In the study, titled “Neurochemical Aftermath of Repetitive Mild Traumatic Brain Injury” the authors reviewed 16 athletes with a history of Post Concussion Syndrome (approximately half of which recovered within a year and the others having persistent symptoms beyond a year) along with a control group.  Neurofilament light proteins were significantly increased in players with PCS for more than 1 year and players with PCS had significantly lower cerebrospinal fluid amyloid-β levels compared with control individuals.

The authors concluded that these biomarkers could potentially be used to help screen athletes showing signs of too much damage which could, in turn, help athletes make a more informed retirement decision from combative and other contact sports.

Here is the study’s full abstract:

Importance  Evidence is accumulating that repeated mild traumatic brain injury (mTBI) incidents can lead to persistent, long-term debilitating symptoms and in some cases a progressive neurodegenerative condition referred to as chronic traumatic encephalopathy. However, to our knowledge, there are no objective tools to examine to which degree persistent symptoms after mTBI are caused by neuronal injury.

Objective  To determine whether persistent symptoms after mTBI are associated with brain injury as evaluated by cerebrospinal fluid biochemical markers for axonal damage and other aspects of central nervous system injury.

Design, Settings, and Participants  A multicenter cross-sectional study involving professional Swedish ice hockey players who have had repeated mTBI, had postconcussion symptoms for more than 3 months, and fulfilled the criteria for postconcussion syndrome (PCS) according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) matched with neurologically healthy control individuals. The participants were enrolled between January 2014 and February 2016. The players were also assessed with Rivermead Post Concussion Symptoms Questionnaire and magnetic resonance imaging.

Main Outcomes and Measures  Neurofilament light protein, total tau, glial fibrillary acidic protein, amyloid β, phosphorylated tau, and neurogranin concentrations in cerebrospinal fluid.

Results  A total of 31 participants (16 men with PCS; median age, 31 years; range, 22-53 years; and 15 control individuals [11 men and 4 women]; median age, 25 years; range, 21-35 years) were assessed. Of 16 players with PCS, 9 had PCS symptoms for more than 1 year, while the remaining 7 returned to play within a year. Neurofilament light proteins were significantly increased in players with PCS for more than 1 year (median, 410 pg/mL; range, 230-1440 pg/mL) compared with players whose PCS resolved within 1 year (median, 210 pg/mL; range, 140-460 pg/mL) as well as control individuals (median 238 pg/mL, range 128-526 pg/mL; P = .04 and P = .02, respectively). Furthermore, neurofilament light protein concentrations correlated with Rivermead Post Concussion Symptoms Questionnaire scores and lifetime concussion events (ρ = 0.58, P = .02 and ρ = 0.52, P = .04, respectively). Overall, players with PCS had significantly lower cerebrospinal fluid amyloid-β levels compared with control individuals (median, 1094 pg/mL; range, 845-1305 pg/mL; P = .05).

Conclusions and Relevance  Increased cerebrospinal fluid neurofilament light proteins and reduced amyloid β were observed in patients with PCS, suggestive of axonal white matter injury and amyloid deposition. Measurement of these biomarkers may be an objective tool to assess the degree of central nervous system injury in individuals with PCS and to distinguish individuals who are at risk of developing chronic traumatic encephalopathy.

In the last decade there has been great progress in public understanding that concussions are a form of traumatic brain injury, not simply ‘getting your bell rung’.

Current studies are showing, however, that sub-concussive blows over a prolonged period are equally troubling and a recent article published in the Journal of Neurosurgery Clinics of North America highlights this.

In short the authors of the article, titled “Repetitive Head Impacts and Chronic Traumatic Encephalopathy” note current literature indicates that “the number of years of exposure to contact sports, not the number of concussions, is significantly associated with more severe tau pathology in CTE, suggesting that repetitive head trauma, including sub-concussive injury, is the primary stimulus for the disease” a message that should resonate to all who choose to pursue either amateur or professional combative sports.


The full article can be purchased here.



One topic I often revisit is the reality that gloves in combative sports such as boxing, kickboxing and MMA do a great job protecting from superficial injury but likely lead to an increase of traumatic brain injury and CTE.

This week I had the pleasure of picking up a hard copy of Jason Thalken’s “Fight Like a Physicist who after experimentation published the following sober comments that regulators should consider next time they revisit sanctioning a gloveless combat sports event –

Boxing gloves and MMA gloves are effective at absorbing and dispersing the energy of impact, which causes local tissue damage, but we have no reason to believe any gloves reduce momentum transfer.  In fact, thanks to the excellent hand protection gloves provide, fighters are able to punch with greater momentum than they would with bare knuckles, and they are able to attack hard targets like the head more often.  This means gloves do a great job of reducing the types of injuries associated with structural tissue damage (cuts, bruises, swelling, black eyes, and broken bones), but they also lead to an increase in the frequency and intensity of momentum transfer to the brain, which is directly related to diffuse axonal injury and CTE.

Fifty years ago, before we had a firm understanding of CTE, the choice was clear; use padded gloves to prevent injury.  Today we need to think a little harder.  A cut, a broken hand or an eye injury might stop a fight or even end a fighter’s career, but brain injury can take away a fighter’s ability to function as a human being, both in and out of the ring


Adding to this site’s archived articles addressing rapid extreme weight cut practices in combat sports, a recent study was published in the Journal of The Physician and Sports Medicine evaluating competition results in boxing with athletes who practiced Rapid Weight Gain after weigh ins.

In the study, titled Rapid Weight Gain in Professional Boxing and Correlation With Fight Decisions, the authors reviewed 71 bouts sanctioned by the International Boxing Federation and looked at how much weight athletes gained from weigh in to competition and further reviewed the weight discrepancy between opponents.

The data revealed that “correlations between weight gain and weight discrepancy were not found” although there were cases with “alarming” weight gain and weight discrepancy.

Below is the studies full abstract:

Introduction: Boxing is a sport where athletes compete in several weight categories. Professional boxers typically dehydrate to cut their weight for the weigh-in (24h before the contest) and then rehydrate before the fight. The International Boxing Federation (IBF) mandates a second weigh-in 12h before the fight.

Objectives: 1) To quantify the weight gain (WG) from the 1st to the 2nd weigh-in; 2) to investigate whether rapid WG affects boxing performance (win/loss rate) and 3) whether weight discrepancy (WD) between boxers exposes them to increased health risks (rate of fights ended before time limit).

Methods: From official weigh-in reports of 71 IBF fights (142 fighters) the following data were gathered/calculated for each boxer: age, weight division, 1st weight, 2nd weight, WG between weigh-ins (kg and %), WD between opponents, and fight decision.

Results: Between the weigh-ins, the average WG was 2.52±1.37kg (range -0.3/6.4kg) and 3.8±2.2% of the initial body weight (range -0.4/9.3%) and the average WD 1.94±1.50kg (maximum 7.10kg). Both WG and WD did not affect match outcomes. We observed tendencies for higher loss rate among boxers gaining more weight, and for higher victory rate in boxers with larger WD, however without reaching significance. A significant negative correlation was found between the 1st weight and the WG, both in absolute (r=-0.278, p=0.001) and relative value (r=-0.497, p<0.0001).

Conclusions: Although correlations between WG, WD and boxing performance were not found, single cases with an alarming high WG and WD were noted.

Adding to this site’s archives of combat sports safety studies, The Journal of Sports Health published a data review concluding that MMA combatants suffer an in competition injury rate between 22.9 and 28.6%.

In the recent study the authors reviewed 35 years of publications detailing injury rates in MMA or thier component sports.  The data revealed that “The majority of studies on MMA injuries evaluate those sustained during competition, which range in incidence from 22.9 to 28.6 per 100 fight-participations. Striking-predominant disciplines such as boxing, karate, and Muay Thai have high rates of head and facial injuries, whereas submission-predominant disciplines such as Brazilian jiu-jitsu, judo, and wrestling have high rates of joint injuries.

The study is titled “Injuries Sustained by the Mixed Martial Arts Athlete” and the full article can be purchased here.

In my latest review of safety studies in the world of combative sports, a recent article was published in the British Journal of Sports Medicine finding concussion ‘preventing’ sports equipment has ‘no effect’.
In the recent study, titled “Current State of Concussion Prevention Strategies: a systemic review and meta-analysis of prospective, controlled studies” the authors evaluated 14 studies reviewing the effects of “novel protective equipment“.  They concluded that while some equipment was effective in reducing “superficial head injury” (think cuts and bruises) when it came to concussion prevention the equipment “showed no effect of intervention“.

The study’s full abstract is reproduced below:


Objective The aim of the current review was to systematically identify, evaluate and synthesise trials that examine concussion prevention via equipment, educational programmes and training programmes.

Data sources PubMed and EBSCO host (CINAHL, MEDLINE, SPORTDiscus).

Eligibility criteria for selecting studies The electronic databases PubMed and EBSCO were searched using the phrases: concussion prevention equipment, concussion prevention trainingand concussion prevention education. Included studies utilised a prospective study design to evaluate the preventative effect of: (1) equipment, (2) training or (3) educational programmes on the incidence of concussions in comparison to a control group.

Data extraction Demographic data and intervention methods were recorded. Intervention and control group concussion rates and superficial head injury rates were extracted and combined using random-effects relative risk meta-analysis.

Results 14 studies evaluated interventions of novel protective equipment. One prospective investigation evaluated an educational programme. The relative risk of concussion for participants enrolled in the interventional arms of trials was not significantly different from that in standard practice arms (RR=0.78, 95% CI 0.55 to 1.11, χ2=1.8, p=0.17; I2=85.3%, 95% CI 71.5% to 90.8%). The relative risk of concussion for participants wearing protective equipment (ie, headgear, full face shields) relative to their counterparts wearing standard or no equipment, calculated from seven available reports, showed no effect of intervention (RR=0.82, 95% CI 0.56 to 1.20, χ2=1.06, p=0.30; I2=86.7%, 95% CI 73.3% to 91.8%). The relative risk of superficial head injury for participants wearing protective equipment relative to their counterparts, calculated from three reports, showed a significant risk reduction (RR=0.41, 95% CI 0.31 to 0.56, χ2=34.13, p<0.0001; I2=53.1%, 95% CI 0% to 85.2%).

Conclusions Prospective controlled studies indicate that certain protective equipment may prevent superficial head injury, but these items are suboptimal for concussion prevention in sport.

Adding to this site’s archived summaries of studies addressing safety issues in combat sports, a recent study was published in the Journal of Neuroradiology canvassing the extent of objective white matter disturbance in the brains of amateur boxers compared to a control group.

The study, titled Reduced White Matter Integrity in Amateur Boxers, posed the question of whether amateur boxers would have white matter disturbance detectable on imaging given the greater safety protocols in place at the amateur level.  The study conducted  diffusion tensor imaging of the brains of 31 amateur boxers an compared these to a non boxing peer group.

The study found that “revealed widespread white matter disturbance partially related to the individual fighting history in amateur boxers. These findings closely resemble those in patients with accidental TBI and indicate similar histological changes in amateur boxers.

The full abstract is reproduced below –


Professional boxing can lead to chronic traumatic encephalopathy, a variant of traumatic brain injury (TBI). Its occurrence in amateur boxers is a matter of debate since amateur boxing is considered to be less harmful due to more strict regulations. However, several studies using different methodological approaches have revealed subtle signs of TBI even in amateurs. Diffusion tensor imaging (DTI) is sensitive to microscopic white matter changes and has been proven useful in TBI when routine MR imaging often is unrevealing.


DTI, with tract-based spatial statistics (TBSS) together with neuropsychological examination of executive functions and memory, was used to investigate a collective of 31 male amateur boxers and 31 age-matched controls as well as a subgroup of 19 individuals, respectively, who were additionally matched for intellectual performance (IQ).


All participants had normal findings in neurological examination and conventional MR. Amateur boxers did not show deficits in neuropsychological tests when their IQ was taken into account. Fractional anisotropy was significantly reduced, while diffusivity measures were increased along central white matter tracts in the boxers group. These changes were in part associated with the number of fights.


TBSS revealed widespread white matter disturbance partially related to the individual fighting history in amateur boxers. These findings closely resemble those in patients with accidental TBI and indicate similar histological changes in amateur boxers.