Archive for the ‘Safety Studies’ Category

NoteThe below findings likely exclude concussions which appear to be “significantly underreported” with the authors noting that 40% of contests end in KO/TKO and concussions are likely in many of these bouts.  In other words, the study finds there is a 39% reported injury rate in kickboxing bouts in addition to the likely brain trauma that comes from bouts ending in KO/TKO


In the latest safety study addressing combat sports, professional and amateur kickboxing records were reviewed revealing 39% injury rate for competitors.

In the recent study, titled Injuries to Professional and Amateur Kickboxing Contestants, published this month in the Orthopaedic Journal of Sports Medicine, the authors obtained and reviewed data describing fight outcomes and injuries sustained during professional and amateur kickboxing contests over a 15-year period from the official records of the Nevada Athletic Commission.

The records revealed an overall injury incidence rate of 390.1 injuries per fighter per 1000 contests.

The data further showed that professional fighters were 2.5 times more likely to get injured compared with amateurs.

The most commonly injured anatomic regions were the head (57.8%) and lower extremity (26.1%), while the most common types of injury were laceration (70.6%) and fracture (20.6%).

Study Table 1

The full study can be found here – Injuries to Professional and Amateur Kickboxing Contestants

Chronic Traumatic Encephalopathy (CTE), a brain disorder related to repetative traumatic brain injury is perhaps one of the most troubling risks associated with the world of contact sports.  As the medical industry better understands this progressive disease the link between prolonged exposure to sub concussive blows and the disease becomes ever clearer.  To this end a study was recently published in the journal Acta Neuropathologica showing just how strong the link is.

In the study, titled “Chronic traumatic encephalopathy pathology in a neurodegenerative disorders brain bank” the authors accessed a brain bank and processed samples for tau immunohistochemistry.  Medical records were cross referenced to determine if the samples came from individuals with a history of contact sports participation.  The study revealed as follows

  • 21 of 66 former athletes had cortical tau pathology consistent with CTE
  • CTE pathology was not detected in 198 individuals without exposure to contact sports, including 33 individuals with documented single-incident TBI sustained from falls, motor vehicle accidents, domestic violence, or assaults
  • CTE pathology was only detected in individuals with documented participation in contact sports

The authors conclude that “exposure to contact sports was the greatest risk factor for CTE pathology”.

The study’s abstract can be found here .

There are many documented cases of injury in MMA due to the profound dehydration that comes with rapid extreme weight cutting.  Perhaps the most dangerous risk is that of increased brain trauma and death that comes from being exposed to strikes while not being fully hydrated.  As this industry wide practice is becoming better recognized by the public more calls for regulatory reform are being made.

The latest comes from the British Journal of Sports Medicine who, this month, published an article reviewing local rapid extreme weight cut practices and noted “an alarming culture of weight making.”.

The practices from the athletes surveyed revealed as follows –

  • In total, 67% of athletes engaged in a previously unreported practice of ‘waterloading’, whereby athletes reduce sodium intake and overdrink water (eg, 20–23 Lover 3 days), in the belief it will trigger a ‘flushing mode’ to induce excessive urine production.
  • Several athletes (17%) reported the use of solutions to increase sweating by increasing circulation
    eg, Sweet sweat) or by blocking the pores (eg, Albolene).
  • Athletes (37%) consumed prescription and over-the-counter diuretics and
  • 13% utilized intravenous lines (1 self-administered, 3 administered by a physician) and glycerol to encourage rehydration post-weigh-in.
  • In total, 73% of athletes consumed nutritional supplements during weight-cutting, though 61% did not know whether supplements were tested for banned substances
  • One hundred per cent of the MMA athletes engaged in complete fasting or low carbohydrate diets in the final 3–5 days prior to weigh-in thereby promoting ‘relative energy deficiency’
  • Only 20% of athletes obtained dietary advice from qualified sports dietitians/nutritionists, with the majority of advice provided from coaches, peers and internet sources.

The physicians called for regulatory reform for these practices, including the practice I have been most vocal about, namely adding a hydration requirement for athletes when they make weight.  Yes this will drastically alter the current landscape of weight classes athletes are used to competing in but it will restore sanity to the reason weight classes exist in the first place – protection of the fighters,

Specifically the  BJSM requests that regulators schedule “weigh-ins 24 h or less before competition alongside minimal hydration acceptable limits.

The full study can be found here – Alarming Weight Cutting Practices in MMA

In my ongoing effort to highlight safety studies addressing combative sports, a thesis paper was recently published by the University of Ottawa’s Interdisciplinary School of Health Sciences reviewing factors associated with head trauma in professional MMA.

The author analysed data from Fightmetric reviewing 7,134 rounds in the UFC, WEC and Strikeforce from 2004 – 2014.  The study noted several factors linked to higher rate of concussion, two of which were fighter age (older fighters being more susceptible to concussion) and time between bouts (with a shorter period between bouts being linked to a higher concussive rate).  On these points the author notes as follows –

Increasing age is positively associated with head trauma (p<.05; OR 3.2). Prolonging the time period in between fights is protective against head trauma (p<.05; OR 0.81)…

…the age at which a fighter steps into the octagon is associated with head trauma. The older the fighter, the more likely he or she is to suffer a concussion…

Moreover, the number of months in between a combatants fights is detrimental to the discussion of concussion in MMA. The more time, in months, the fighters spend resting or training prior to their next fight the less chance they will suffer a concussion during the fight. Strong evidence is lacking to identify an appropriate time-frame that fighters should adhere to before initiating training for their next fight..

The full study can be found here – Factors Associated With Head Trauma Among Professional Mixed Martial Arts Athletes

Given that CTE is being linked to duration and severity of contact and further that the KO rate by punches in MMA increased tenfold after gloves with conventional wraps became the norm in the sport, should MMA and other striking sport athletes use ‘padded’ hand wraps to reduce brain trauma while sparring?  An article published this week in the International Journal of Kinesiology and Sports Science suggests so.

In the recent article, titled “The Influence of a Padded Hand Wrap on Punching Force in Elite and Untrained Punchers” the authors had 14 trained fighters and 24 untrained individuals punch at maximum power with gloves and conventional wraps and then again with “an additional 1.2cm thick cylinder 4g foam-like pad placed over the knuckles”.  The tests revealed that the additional padding reduced punching force by 8.9% for the untrained individuals and 12.6% for the trained fighters.

Graphic from padded punching power study

The authors conclude that “Practitioners should consider utilizing hand-padding strategies such as this during practice/sparring as the reduction in punching force will likely have important long-term health implications for both the puncher and the person absorbing the punch.“.

The full study can be found here – The Influence of a Padded Hand Wrap on Punching Force

Whether or not adding padding to training hand wraps helps address TBI in combat sports all athletes would be wise to remember that the accumulation of sub concussive trauma likely leads to CTE and methods which respect long term brain health should be first and foremost in any training program.

In the latest article addressing injury issues in combative sports, a study was published last month in the Journal of Neurotrauma studying cognitive impairment from boxing.

The study, titled Chronic Effects of Boxing: DTI and Cognitive Findings, used Magnetic Resonance Imaging and Diffusion Tensor Imaging to study brain trauma among 10 boxers (9 active and 2 retired) and 9 other participants not involved in combative sports.

Unsurprisingly the study noted cognitive issues among the boxers and, consistent with other recent studies, pointed to the number of years involved in the sport, as an important factor leading to long term impairment.

To this point the study concluded “Years of boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r=-.74, p=0.02), delayed recall (r=-0.83, p=0.003), and serial RT, (r=.66, p=0.05).”

The full abstract can be found here

We used magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to evaluate the effects of boxing on brain structure and cognition in 10 boxers (8 retired, 2 active) (mean age=45.7 years, SD=9.71) and nine participants (mean age=43.44, SD=9.11) in non-combative sports. Evans Index (maximum width of the anterior horns of the lateral ventricles/maximal width of the internal diameter of the skull) was significantly larger in the boxers, (F=4.52, p=0.050; Cohen’s f=0.531). Word list recall was impaired in the boxers ((F1,14)=10.70, p=0.006, f=0.84)) whereas implicit memory measured by faster reaction time (RT) to a repeating sequence of numbers than to a random sequence was preserved t=2.52, p<0.04. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) measured by tractography did not significantly differ between the groups. However, DTI metrics were significantly correlated with declarative memory (e.g., left ventral striatum ADC with delayed recall, r=-0.74, p=0.02) and with RT to the repeating number sequence, (r=0.70, p=0.04) in the boxers. Years of boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r=-.74, p=0.02), delayed recall (r=-0.83, p=0.003), and serial RT, (r=.66, p=0.05). We conclude that microstructural integrity of white matter tracts is related to declarative memory and response speed in boxers and to the extent of boxing exposure. Implications for chronic traumatic encephalopathy are discussed.

One of the latest safety studies addressing combat sports, published last month in the journal Australasian Epidemiologist, the author compiled data from a total of 47 observational studies addressing injuries in combat sports.  Specifically the author looked for the injury incidence rate, injury patterns and injury severity rates in 6 different sports, namely boxing, judo, karate, kickboxing, mixed martial arts, and taekwondo.

The study found that sports with a striking element had the greatest injury rate with MMA leading the pack followed by boxing and the other striking sports and with Judo having the lowest injury rate of the group.

In terms of injury patterns the study found that “The head and neck was the most frequently injured anatomical region in boxing (84%), karate (74%), mixed martial arts (64%), and kickboxing (55%); whereas the lower limb and upper limb were the most frequently anatomical regions in taekwondo (51%) and judo (47%), respectively.

Lastly, in terms of injury severity the study was lacking data on boxing, MMA and kickboxing.  Of the remainign sports the study concluded that “the proportion of moderate to severe injuries (i.e. injuries resulting in more than one week of time lost from play) was 32% in taekwondo. 15% in karate. and 7% in judo.

I should mention that a recent study published addressing MMA and boxing injury severity rates noting that while MMA had a greater overall injury rate than boxing, boxing injuries tended to be more severe.

The full study can be found here – Epidemiology of injuries in full-contact combat sports

The study included the following helpful visual charts –

Figure 1 Figure 2

Figure 3

Figure 4

Adding to this site’s archived safety studies in combat sports, a study was recently published in the British Journal of Sports Medicine suggesting headguards can reduce concussions in combat sports.

The authors, McIntosh and Patton, recently authored another article suggesting the quality of headguards can make a significant difference in effectiveness, noted in the new study, titled Boxing Headguard Performance in Punch Machine Tests that “The data support the opinion that current AIBA headguards can play an important role in reducing the risk of concussion and superficial injury in boxing competition and training.”.

Here is the study’s abstract –

Background The paper presents a novel laboratory method for assessing boxing headguard impact performance. The method is applied to examine the effects of headguards on head impact dynamics and injury risk.

Methods A linear impactor was developed, and a range of impacts was delivered to an instrumented Hybrid III head and neck system both with and without an AIBA (Association Internationale de Boxe Amateur)-approved headguard. Impacts at selected speeds between 4.1 and 8.3 m/s were undertaken. The impactor mass was approximately 4 kg and an interface comprising a semirigid ‘fist’ with a glove was used.

Results The peak contact forces were in the range 1.9–5.9 kN. Differences in head impact responses between the Top Ten AIBA-approved headguard and bare headform in the lateral and forehead tests were large and/or significant. In the 8.3 m/s fist-glove impacts, the mean peak resultant headform accelerations for bare headform tests was approximately 130 g compared with approximately 85 g in the forehead impacts. In the 6.85 m/s bare headform impacts, mean peak resultant angular head accelerations were in the range of 5200–5600 rad/s2 and almost halved by the headguard. Linear and angular accelerations in 45° forehead and 60° jaw impacts were reduced by the headguard.

Conclusions The data support the opinion that current AIBA headguards can play an important role in reducing the risk of concussion and superficial injury in boxing competition and training.

While measuring impact dynamics is one factor, there is still controversy on the issue of whether headguards lead to less or more concussions.  For some practical contrary views from combat sports athletes I suggest reading this article by Ben Fowlkes which highlights some fighters’ experiences with issues such as sparring partners hitting harder when headgear is in use and also the feeling that more shots land due to the bigger target created with headgear.

Adding to this site’s archives canvassing safety studies in combat sports, a study was recently published in The Clinical Journal of Sports Medicine comparing boxing and MMA injury rates over a 13 year period.

The study, titled Combative Sports Injuries: An Edmonton Retrospective, reviewed post fight medical exams for combat sports bouts in Edmonton from 2000-2013.  The study reports that while MMA athletes suffer a greater overall injury rate than boxers, the injuries tend to be more trivial (ie contusions and bruising) whereas boxers suffer a higher incidence of serious injuries such as brain trauma and eye injuries.

The study’s Abstract reads as follows –

Objective: Mixed martial arts (MMA) is an increasingly popular combative sport involving aggressive techniques that present substantial injury risk. We examined the incidence and types of injuries sustained in MMA fights and compared this with injuries sustained in boxing matches.

Design: Consecutive Case Series.

Setting: We used data from post-fight medical examinations on all bouts in Edmonton, Canada, between 2000 and 2013.

Participants: The participants were 1181 MMA competitors and 550 boxers.

Main Outcome Measures: The attending physician conducted a mandatory post-fight examination of all fighters and documented the nature of injuries sustained.

Results: Boxers were significantly more likely not to experience injury (49.8% vs 59.4%, P < 0.001), whereas MMA fighters were significantly more likely to experience 1 injury (typically contusion/bruising, P < 0.001). Boxers were more likely to experience loss of consciousness (7.1% vs 4.2%, P = 0.01) and serious eye injury (1.1% vs 0.3%, P = 0.02).

Conclusions: The overall injury incidence in MMA competitors appears slightly higher than for boxers, but MMA fighters experience more minor contusion/bruising injuries. Boxers are more likely to experience serious injury such as concussion/head trauma involving loss of consciousness or eye injury such as retinal detachment.

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.