The damaging punch

Incidence of injury in professional mixed martial arts competitions

Mixed Martial Arts (MMA) competitions were introduced in the United States with the first Ultimate Fighting Championship (UFC) in 1993. In 2001, Nevada and New Jersey sanctioned MMA events after requiring a series of rule changes. The purpose of this study was to determine the incidence of injury in professional MMA fighters. Data from all professional MMA events that took place between September 2001 and December 2004 in the state of Nevada were obtained from the Nevada Athletic Commission. Medical and outcome data from events were analyzed based on a pair-matched case-control design. Both conditional and unconditional logistic regression models were used to assess risk factors for injury. A total of 171 MMA matches involving 220 different fighters occurred during the study period. There were a total of 96 injuries to 78 fighters. Of the 171 matches fought, 69 (40.3%) ended with at least one injured fighter. The overall injury rate was 28.6 injuries per 100 fight participations or 12.5 injuries per 100 competitor rounds. Facial laceration was the most common injury accounting for 47.9% of all injuries, followed by hand injury (13.5%), nose injury (10.4%), and eye injury (8.3%). With adjustment for weight and match outcome, older age was associated with significantly increased risk of injury. The most common conclusion to a MMA fight was a technical knockout (TKO) followed by a tap out. The injury rate in MMA competitions is compatible with other combat sports involving striking. The lower knockout rates in MMA compared to boxing may help prevent brain injury in MMA events. Key PointsMixed martial arts (MMA) has changed since the first MMA matches in the United States and now has increased safety regulations and sanctioning.MMA competitions have an overall high rate of injury.There have been no MMA deaths in the United States.The knockout (KO) rate in MMA appears to be lower than the KO rate of boxing matches.MMA must continue to be supervised by properly trained medical professionals and referees to ensure fighter safety in the future.

Concussion in professional football: comparison with boxing head impacts--part 10

OBJECTIVE

This study addresses impact biomechanics from boxing punches causing translational and rotational head acceleration. Olympic boxers threw four different punches at an instrumented Hybrid III dummy and responses were compared with laboratory-reconstructed NFL concussions.

METHODS

Eleven Olympic boxers weighing 51 to 130 kg (112-285 lb) delivered 78 blows to the head of the Hybrid III dummy, including hooks, uppercuts and straight punches to the forehead and jaw. Instrumentation included translational and rotational head acceleration and neck loads in the dummy. Biaxial acceleration was measured in the boxer's hand to determine punch force. High-speed video recorded each blow. Hybrid III head responses and finite element (FE) brain modeling were compared to similarly determined responses from reconstructed NFL concussions.

RESULTS

The hook produced the highest change in hand velocity (11.0 +/- 3.4 m/s) and greatest punch force (4405 +/- 2318 N) with average neck load of 855 +/- 537 N. It caused head translational and rotational accelerations of 71.2 +/- 32.2 g and 9306 +/- 4485 r/s. These levels are consistent with those causing concussion in NFL impacts. However, the head injury criterion (HIC) for boxing punches was lower than for NFL concussions because of shorter duration acceleration. Boxers deliver punches with proportionately more rotational than translational acceleration than in football concussion. Boxing punches have a 65 mm effective radius from the head cg, which is almost double the 34 mm in football. A smaller radius in football prevents the helmets from sliding off each other in a tackle.

CONCLUSION

Olympic boxers deliver punches with high impact velocity but lower HIC and translational acceleration than in football impacts because of a lower effective punch mass. They cause proportionately more rotational acceleration than in football. Modeling shows that the greatest strain is in the midbrain late in the exposure, after the primary impact acceleration in boxing and football.

Injury risk in professional boxing

OBJECTIVE

Although a popular endeavor, boxing has fallen under increased scrutiny because of its association with traumatic brain injury. However, few studies have investigated the overall epidemiology of boxing injuries from representative samples, and no study has ever documented the incidence of injuries in female boxers. This study is a review of professional boxing data from the state of Nevada from September 2001 through March 2003.

MATERIALS AND METHODS

Medical and outcome data for all professional boxing matches occurring in Nevada between September 2001 and March 2003 (n = 524 matches) were analyzed on the basis of a pair-matched, case-control design. Cases were boxers who received an injury during the boxing matches. Boxers who were not injured served as control subjects. Both conditional and unconditional logistic regression models were used to assess risk factors for injury.

RESULTS

The overall incidence rate of injury was 17.1 per 100 boxer-matches, or 3.4 per 100 boxer-rounds. Facial laceration accounted for 51% of all injuries, followed by hand injury (17%), eye injury (14%), and nose injury (5%). Male boxers were significantly more likely than female boxers to receive injuries (3.6 versus 1.2 per 100 boxer-rounds, P = 0.01). Male boxing matches also ended in knockouts and technical knockouts more often than did female matches (P < 0.001). The risk of injury for those who lost the matches was nearly twice the risk for the winners. Those who lost by knockout had double the risk of injury compared with those who lost by other means. Neither age nor weight was significantly associated with the risk of injury.

CONCLUSIONS

The injury rate in professional boxing matches is high, particularly among male boxers. Superficial facial lacerations are the most common injury reported. Male boxers have a higher rate of knockout and technical knockouts than female boxers. Further research is necessary to determine the outcomes of injury, particularly the long-term neurologic outcome differences between sexes.

Biomechanics of the head for Olympic boxer punches to the face

OBJECTIVE

The biomechanics of the head for punches to the jaw and the risk of head injury from translational and rotational acceleration were studied. [figure: see text]

METHODS

Seven Olympic boxers from five weight classes delivered 18 straight punches to the frangible face of the Hybrid III dummy. Translational and rotational head acceleration, neck responses, and jaw pressure distribution were measured. High speed video recorded each blow and was used to determine punch velocity. Equilibrium was used to determine punch force, energy transfer, and power.

RESULTS

Punch force averaged 3427 (standard deviation (SD) 811) N, hand velocity 9.14 (SD 2.06) m/s, and effective punch mass 2.9 (SD 2.0) kg. Punch force was higher for the heavier weight classes, due primarily to a higher effective mass of the punch. Jaw load was 876 (SD 288) N. The peak translational acceleration was 58 (SD 13) g, rotational acceleration was 6343 (SD 1789) rad/s(2), and neck shear was 994 (SD 318) N.

CONCLUSIONS

Olympic boxers deliver straight punches with high impact velocity and energy transfer. The severity of the punch increases with weight class.

No acute changes in postural control after soccer heading

BACKGROUND

Soccer heading has been proposed as a potential cause of cerebral dysfunction.

OBJECTIVE

To examine the acute effects of two types of soccer heading on postural control.

METHODS

Collegiate soccer players were randomly assigned to one of four groups: control, linear heading, simulated rotational heading, or rotational heading. Each subject completed a baseline postural stability assessment on day 1. On day 2 the same assessment was completed for the control subjects. The simulated rotational heading group completed a simulated heading drill before postural stability testing. The linear and rotational heading groups performed a heading drill with 20 balls at 88.71 km/h (55 mph), before postural stability testing. Separate one between (group), three within (surface, eyes, and day), mixed model, repeated measures analyses of variance were conducted on values for total sway and mean centre of pressure.

RESULTS

The mixed model analysis of variance of results showed no significant differences (p>0.05) for the interactions of interest for either variable. Results suggest no acute changes in measures of postural control in soccer players completing either a linear or rotational soccer heading drill of 20 balls at a fixed speed.

CONCLUSION

Non-significant interactions between surface, eyes, day, and group indicate that sensory interaction of the balance mechanism components are not be compromised by the heading drill. This research supports previous studies suggesting that there are no acute risks associated with routine soccer heading. A direct comparison between these findings and those suggesting long term chronic deficits, however, cannot be made. Other studies that report chronic cerebral deficits in soccer players may have resulted from factors other than soccer heading and warrant further examination.

The Efficacy of Soccer Headgear

OBJECTIVE: The potential for risks associated with chronic soccer heading has led some soccer leagues to mandate the use of soccer headgear. Although manufacturers have designed and promoted these headbands to decrease the forces associated with heading a soccer ball, their efficacy has not been tested. Therefore, we investigated the efficacy of 3 brands of soccer headgear: Headers, Headblast, and Protector, as compared with a non-headband condition. DESIGN AND SETTING: A force platform was mounted vertically with each headband attached with a length of hook-and-loop tape. A JUGS Soccer Machine projected balls at the platform and headband at 56.45 kph (35 mph). MEASUREMENTS: We measured vertical ground reaction force for 50 trials of each condition and calculated peak force, time to peak force, and impulse. RESULTS: We found a significant reduction in peak force of impact with all 3 headbands. The Protector headband also showed the greatest decrease in time to peak force and impulse, whereas the Headers headband showed a significant increase in impulse. CONCLUSIONS: All 3 headbands were effective at reducing the peak impact force. The Protector headband appeared the most effective at reducing time to peak force and impulse within the design of this study. The clinical effectiveness of these products remains to be seen.

Variability in the control of head movements in seated humans: a link with whiplash injuries?

The aim of this study was to determine how context and on-line sensory information are combined to control posture in seated subjects submitted to high-jerk, passive linear accelerations. Subjects were seated with eyes closed on a servo-controlled linear sled. They were asked to relax and received brief accelerations either sideways or in the fore-aft direction. The stimuli had an abrupt onset, comparable to the jerk experienced during a minor car collision. Rotation and translation of the head and body were measured using an Optotrak system. In some of the subjects, surface electromyographic (EMG) responses of selected neck and/or back muscles were recorded simultaneously. For each subject, responses were highly stereotyped from the first trial, and showed little sign of habituation or sensitisation. Comparable results were obtained with sideways and fore-aft accelerations. During each impulse, the head lagged behind the trunk for several tens of milliseconds. The subjects' head movement responses were distributed as a continuum in between two extreme categories. The 'stiff' subjects showed little rotation or translation of the head relative to the trunk for the whole duration of the impulse. In contrast, the 'floppy' subjects showed a large roll or pitch of the head relative to the trunk in the direction opposite to the sled movement. This response appeared as an exaggerated 'inertial' response to the impulse. Surface EMG recordings showed that most of the stiff subjects were not contracting their superficial neck or back muscles. We think they relied on bilateral contractions of their deep, axial musculature to keep the head-neck ensemble in line with the trunk during the movement. About half of the floppy subjects displayed reflex activation of the neck muscles on the side opposite to the direction of acceleration, which occurred before or during the head movement and tended to exaggerate it. The other floppy subjects seemed to rely on only the passive biomechanical properties of their head-neck ensemble to compensate for the perturbation. In our study, proprioception was the sole source of sensory information as long as the head did not move. We therefore presume that the EMG responses and head movements we observed were mainly triggered by the activation of stretch receptors in the hips, trunk and/or neck. The visualisation of an imaginary reference in space during sideways impulses significantly reduced the head roll exhibited by floppy subjects. This suggests that the adoption by the central nervous system of an extrinsic, 'allocentric' frame of reference instead of an intrinsic, 'egocentric' one may be instrumental for the selection of the stiff strategy. The response of floppy subjects appeared to be maladaptive and likely to increase the risk of whiplash injury during motor vehicle accidents. Evolution of postural control may not have taken into account the implications of passive, high-acceleration perturbations affecting seated subjects.

Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.

The postconcussion syndrome after mild head trauma: is brain damage overdiagnosed? Part 1

Many investigators attribute the postconcussion syndrome following mild closed head injury to permanent brain damage. The evidence supporting this conclusion is reviewed, including the force necessary to cause permanent brain damage; the basis for determining whether the patient was exposed to sufficient force in the accident to permanently damage the brain; the basis for determining whether the patient actually has permanent brain damage (not just brain dysfunction) traceable to the accident; and whether the location and severity of brain damage is sufficient to account for the postconcussion syndrome.

CONCLUSION

the evidence for permanent traumatic brain damage as the cause of the postconcussion syndrome following mild closed head injury is weak.

The neuropsychiatric aspects of boxing

OBJECTIVE

To review the neuropsychiatry of boxing.

METHOD

This update considers the clinical, neuropsychological, diagnostic, neurobiological, and management aspects of boxing-related brain injury.

RESULTS

Professional boxers with multiple bouts and repeated head blows are prone to chronic traumatic encephalopathy (CTE). Repeated head blows produce rotational acceleration of the brain, diffuse axonal injury, and other neuropathological features. CTE includes motor changes such as tremor, dysarthria, and parkinsonism; cognitive changes such as mental slowing and memory deficits; and psychiatric changes such as explosive behavior, morbid jealousy, pathological intoxication, and paranoia. Screening with neuropsychological tests and neuroimaging may help predict those boxers at risk for CTE.

CONCLUSIONS

Boxing results in a spectrum of CTE ranging from mild, nonprogressive motor changes to dementia pugilistica. Recent emphasis on safety in the ring, rehabilitation techniques, and other interventions do not eliminate the risk for CTE. For this reason, there is an active movement to ban boxing.

Long term effects of closed head injuries in sport

Closed head injury has been defined by several authors, but is not agreed upon. The incidence of closed head injury in sports is relatively small, but because the effects may be catastrophic it is an important topic. Forces may be applied to the head from different directions, which results in different types of lesions. The anatomical and physiological changes with head injury have been suggested to explain head injury outcomes. Effects on intelligence and memory have also been reported. Posture had been proposed as a model to examine the subtle effects of head injury. Vision, vestibular input, and somatosensory input are all involved in maintenance of posture. The interaction of these sensory modalities is also pertinent to posture maintenance. Somatosensory input appears to be improperly processed, while vision and vestibular input seem to compensate for lost somatosensation. Attention to regaining the somatosensory component, rather than waiting for compensation to occur, should be addressed in rehabilitation programmes.

Alcohol induced Parkinsonism in an ex-pugilist

The case of an ex-pugilist who developed a reversible Parkinsonian syndrome in response to ethanol intoxication, is described. The relationship between ethanol abuse and altered function in the nigro-striatal system is examined, and the relationship to boxing encephalopathy is reviewed. The patient described was the third neurological casualty in a family of boxing brothers, and suggestions are made regarding the potential dangers of this sport. The syndrome of alcohol induced Parkinsonism in an ex-pugilist has not previously been described in the literature.

Changes in muscle strength and speed of an unloaded movement after various training programmes

The effect of three different training programmes on the maximal speed of an unloaded movement (a karate punch) was studied. Three movement variables were selected: maximal speed of the hand (Vh,max), maximal speed of the shoulder (Vs,max) and elbow extension speed (theta E) simultaneous with Vh.max. The programmes were: training group 1 (TG 1, n = 8) - karate students, dynamic heavy progressive resistance exercise (incline situp and incline bench press) + punch bag exercise; training group 2 (TG 2, n = 8)-karate students, punch bag training; training group 3 (TG 3, n = 5)-no karate experience, dynamic heavy progressive resistance exercise (as in TG 1). The movement variables were calculated from chrono-cyclo photographic recordings of the punches (100 Hz). The level of significance was set at 5%. Sixteen weeks of training gave the following results: significant increases in dynamic strength in all the training groups (14%-53%). In TG 1 the Vh.max increased significantly from 8.49 m.s-1, SD 1.19 to 9.35 m.s-1, SD 1.29 (10%); Vs.max increased significantly in TG 1 by 32% (2.18 m.s-1, SD 0.56 to 2.87 m.s-1, SD 0.98) and in TG 2 by 14% (2.40 m.s-1, SD 0.61 to 2.74 m.s-1, SD 0.52), and in TG 3 theta E at Vh,max increased significantly from 28.6 rad.s-1, SD 4.3 to 32.2 rad.s-1, SD 4.5 (13%). No significant relationships between the changes in maximal muscle strength and the changes in movement speed were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Boxing and the brain

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