Measurement of accelerations Measurement of accelerations experienced by rodeo ridersexperienced by rodeo riders

Watkins S, Jennings R, Knox T, Andrews D, Plaga J, Ivan C Watkins S, Jennings R, Knox T, Andrews D, Plaga J, Ivan C

AGENDAAGENDA

Rodeo events and recent Rodeo events and recent statisticsstatistics

Sports-related head injurySports-related head injury Accelerometers 101Accelerometers 101 Details of the 2007 pilot studyDetails of the 2007 pilot study Rodeo footage and resultsRodeo footage and results

Background on Rodeo Events:Background on Rodeo Events:Bareback RidingBareback Riding

Rules for the RiderRules for the Rider Properly “mark out” the horse on its Properly “mark out” the horse on its

first jump out of the chute first jump out of the chute Maintain a one-hand hold on the Maintain a one-hand hold on the

rigging throughout the eight-second rigging throughout the eight-second rideride

Spurring is requiredSpurring is required DisqualificationDisqualification

Contacting the equipment, the Contacting the equipment, the animal, or the rider with the his free animal, or the rider with the his free handhand

Failure to “mark out”Failure to “mark out” Basis for ScoringBasis for Scoring

Rider’s control and styleRider’s control and style Rider’s spurring techniqueRider’s spurring technique Horse’s bucking effortsHorse’s bucking efforts

http://www.washburncounty.com/rodeo/garretta.gif

Background on Rodeo Events:Background on Rodeo Events:Bull RidingBull Riding

Rules for the RiderRules for the Rider Maintain a one-hand hold Maintain a one-hand hold

throughout the eight-second ridethroughout the eight-second ride Attempt to remain forward, or Attempt to remain forward, or

"over his hand," at all times"over his hand," at all times Spurring not required Spurring not required

DisqualificationDisqualification Contacting the equipment, the Contacting the equipment, the

animal, or the rider with the his animal, or the rider with the his free handfree hand

Basis for ScoringBasis for Scoring Rider’s control and styleRider’s control and style

Good body positionGood body position Use of the free armUse of the free arm Spurring actionSpurring action

Efforts of the bullEfforts of the bull

http://www.shrinerodeo.com/images/bull-riding.jpg

Recent Injury StatisticsRecent Injury Statistics

Bareback RidingBareback Riding Events produce second Events produce second

largest number of largest number of injuries injuries

Accounts for 20% of Accounts for 20% of competition injuriescompetition injuries

Most common sites of Most common sites of injuryinjury

HeadHead ShoulderShoulder KneeKnee

The Justin Sportsmedicine Team (JSMT) has over twenty-five years of experience The Justin Sportsmedicine Team (JSMT) has over twenty-five years of experience with rodeo injuries and covers approximately twenty percent of PRCA sanctioned with rodeo injuries and covers approximately twenty percent of PRCA sanctioned rodeo performances annually. A recent report released by JSMT examined injury rodeo performances annually. A recent report released by JSMT examined injury

data collected from 1981 to 2005.data collected from 1981 to 2005.

Bull RidingBull Riding Injuries are most Injuries are most

common during this common during this event event

Accounts for 50% of Accounts for 50% of competition injuriescompetition injuries

Most common sites of Most common sites of injuryinjury

HeadHead FaceFace ShoulderShoulder

What do we know about head What do we know about head injury ?injury ?

U.S. StatisticsU.S. Statistics 250,000 - 300,000 sports-related head injuries 250,000 - 300,000 sports-related head injuries

occur annually occur annually Annual costs exceed 1 billion dollarsAnnual costs exceed 1 billion dollars

Rodeo StatisticsRodeo Statistics Most common sites of injury are the head and Most common sites of injury are the head and

face face (16% of injuries)(16% of injuries) Most common major injury is concussion Most common major injury is concussion (>50% of all major injuries)(>50% of all major injuries)

Guskiewicz KM, McCrea M, Marshall SW, et al. Cumulative effects of recurrent concussion in collegiate football players: the NCAA Concussion Study. JAMA 2003;290:2549–55.Guskiewicz KM, Weaver NL, Padua DA, et al. Epidemiology of concussion in collegiate and high school football players. Am J Sports Med 2000;28:643–50.Iverson GL, Gaetz M, Lovell MR, et al. Cumulative effects of concussion in amateur athletes. Brain Injury 2004;18:433–43.

More on concussionMore on concussion Pathophysiology remains a mystery

associated with structural changes? (as with severe TBI) reversible functional changes?

Historical definition Transient disturbance of neurological function caused by

“shaking” of the brain that accompanies low velocity brain injuries

Congress of Neurological Surgeons “consensus” definition A clinical syndrome characterized by the immediate and

transient post-traumatic impairment of neural function such as alteration of consciousness, disturbance of vision or equilibrium due to mechanical forces

Why do we care about Why do we care about concussion?concussion?

Sports concussionSports concussion >90% are mild (no loss of >90% are mild (no loss of

consciousness)consciousness) Carries a high risk of recurrent Carries a high risk of recurrent

concussion concussion (athlete often allowed to compete before (athlete often allowed to compete before

recovery from the initial injury)recovery from the initial injury) Repeat incidents Repeat incidents

Generally more serious Generally more serious Slower to resolveSlower to resolve May result in long-term dysfunction May result in long-term dysfunction

No certainty concerning safe to return No certainty concerning safe to return to competitionto competition

http://apps.uwhealth.org/health/adam/graphics/images/en/17143.jpg

How is concussion How is concussion associated with acceleration?associated with acceleration?

“Acceleration concussion” has been proposed as a general term that can be applied to all forms of traumatic brain injury

Accelerations in the 150–200 g range are known to cause head injury

Little is known about repeated exposure to moderate accelerations

Olvey S, Knox T, Cohn K. The development of a method to measure head acceleration and motion in high-impact crashes. Neurosurgery 54: 672-677, 2004.

Measuring AccelerationMeasuring Acceleration

AccelerometersAccelerometers Many types: some simple, Many types: some simple,

some complexsome complex Basic componentsBasic components

A moveable massA moveable mass A way to determine how A way to determine how

much the mass has movedmuch the mass has moved Can measure linear and Can measure linear and

angular accelerations in angular accelerations in multiple axesmultiple axes

How they workHow they work When no forces are presentWhen no forces are present

The mass does not moveThe mass does not move Mechanical: Spring is not stretchedMechanical: Spring is not stretched Electrical: The voltage is equal at all platesElectrical: The voltage is equal at all plates

When forces are presentWhen forces are present The mass is displacedThe mass is displaced

Mechanical: The spring is stretchedMechanical: The spring is stretched Electrical: The voltage at the nearer plates Electrical: The voltage at the nearer plates

increasesincreases

The PhysicsThe Physics

Force acting on the mass is calculated by the Force acting on the mass is calculated by the distance the mass has moved and the inherent distance the mass has moved and the inherent properties of the systemproperties of the system

Measured displacement & stiffness (k) of the springMeasured displacement & stiffness (k) of the spring oror Change in voltage & current applied to the circuitChange in voltage & current applied to the circuit

F=ma is used to calculate the accelerationF=ma is used to calculate the acceleration

With a mass that shifts up and down, left and right, With a mass that shifts up and down, left and right, and back and forth, movement can be measured in and back and forth, movement can be measured in

three dimensions.three dimensions.

The ear-mounted, The ear-mounted, tri-axial accelerometertri-axial accelerometer

Designed by Olvey, Knox et alDesigned by Olvey, Knox et al Impetus for designImpetus for design

In crash situations, driver’s custom In crash situations, driver’s custom fitted ear-mounted communications fitted ear-mounted communications devices remained seated in the ear devices remained seated in the ear canalcanal

Small, tri-axial accelerometers Small, tri-axial accelerometers could be embedded within the could be embedded within the earpiece to allow for head-centered earpiece to allow for head-centered measurements of accelerationmeasurements of acceleration

Initially used to examine head Initially used to examine head accelerations in race car driversaccelerations in race car drivers

Olvey S, Knox T, Cohn K. The development of a method to measure head acceleration and motion in high-impact crashes. Neurosurgery 54: 672-677, 2004.

Goals of the studyGoals of the study

To demonstrate the ability to obtain precise To demonstrate the ability to obtain precise measurements of the accelerations experienced measurements of the accelerations experienced by professional rough stock riders during rodeo by professional rough stock riders during rodeo eventsevents

To use the knowledge gained toward the design To use the knowledge gained toward the design of the first large scale study of the accelerations of the first large scale study of the accelerations encountered during such eventsencountered during such events

To use the acceleration data gained to better To use the acceleration data gained to better understand the pathomechanics of head injury understand the pathomechanics of head injury and assist in the creation of injury prevention and assist in the creation of injury prevention techniquestechniques

Preparatory StepsPreparatory Steps

UTMB IRB approval obtainedUTMB IRB approval obtained Subjects selectedSubjects selected

Two male professional rough stock Two male professional rough stock riders riders

Recruited at rodeo events preceding Recruited at rodeo events preceding the Houston Livestock Show and the Houston Livestock Show and RodeoRodeo

Informed consent obtainedInformed consent obtained Custom mold of the ear canals Custom mold of the ear canals

mademade Accelerometer systems inserted Accelerometer systems inserted

into each mold into each mold

Houston Livestock Show and RodeoHouston Livestock Show and RodeoMarch 6, 2007March 6, 2007

Minutes prior to the competition eventMinutes prior to the competition event Each subject was assisted in inserting his earpieceEach subject was assisted in inserting his earpiece Small wires connecting the earpieces to the recording Small wires connecting the earpieces to the recording

device were secured to the rider’s clothingdevice were secured to the rider’s clothing Data recorder was placed into a padded belt and Data recorder was placed into a padded belt and

fastened around the rider’s waistfastened around the rider’s waist On entering the chuteOn entering the chute

Data recorder was activatedData recorder was activated Rider participated in his scheduled event as usual Rider participated in his scheduled event as usual

After the eventAfter the event Data recorder was collectedData recorder was collected Information transferred to computer for further analysisInformation transferred to computer for further analysis

Houston Livestock Show Houston Livestock Show and Rodeoand Rodeo

March 6, 2007March 6, 2007

A sample of the dataA sample of the data

00HEADLE00H3ACXP (g)

-30

-20-10

010

20

3040

50

82 87 92 97 102

Time (Seconds)

ResultsResults

Bareback RiderBareback Rider 8 seconds of ride completed8 seconds of ride completed No report of injuryNo report of injury Resultant maximum acceleration: 46 g’s!Resultant maximum acceleration: 46 g’s!

Bull RiderBull Rider Failed to complete rideFailed to complete ride No report of injuryNo report of injury Resultant maximum acceleration: 26 g’sResultant maximum acceleration: 26 g’s

ConclusionsConclusions

Human data on acceleration forces in Human data on acceleration forces in rodeo events are lackingrodeo events are lacking

Although it is understood that sports-Although it is understood that sports-related concussions are common and related concussions are common and dangerous to riders, little is known about dangerous to riders, little is known about pathomechanicspathomechanics

Further studies on the effects of frequent Further studies on the effects of frequent exposure to accelerations (<50g) are exposure to accelerations (<50g) are needed for better risk assessmentneeded for better risk assessment

What’s NextWhat’s Next Large scale study at the 2008 Houston Large scale study at the 2008 Houston

RodeoRodeo 8 bareback riders8 bareback riders 8 bull riders8 bull riders

Aerobatic acceleration studyAerobatic acceleration study Details TBDDetails TBD

AcknowledgementsAcknowledgements

J. Pat Evans Research Foundation J. Pat Evans Research Foundation

for the funding provided to support this researchfor the funding provided to support this research Justin Sportsmedicine Team Justin Sportsmedicine Team Houston Livestock Show and RodeoHouston Livestock Show and Rodeo Professional Rodeo Cowboys AssociationProfessional Rodeo Cowboys Association United States Air Force Research United States Air Force Research

LaboratoryLaboratory