University of Vermont AAHS

February 1996, Vol. VI, Number 1

Table of Contents

Why Not Use A Bicycle Helmet for Horseback Riding?
New Mexico Safety Equestrian Project
Hyperkalemic Periodic Paralysis: HyPP
The National Jockey Injury Study
Are Deer Warning Devices a Danger to Horses?
Nevada Trauma Register for Horse Accidents

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Why Not Use A Bicycle Helmet for Horseback Riding?

Why would a horseback rider choose a helmet made for another sport, rather than one which was specifically designed for riding and certified to pass the toughest riding helmet standard in the world?

The argument has been made that U. S, bicycle helmets are similar to helmets made to American Society of Testing and Materials (ASTM) Standard F1163 and certified by the Safety Equipment Institute (SEI). On the surface there are many similarities in testing systems and requirements. However, there are some key differences, and an educated consumer needs to consider these carefully.

ASTM/SEI helmets are made in Western and English styles, come in many colors and styles, are cooler than the "item of apparel" black hunt cap, and weigh as little as 10 1/2 ounces. ASTM/SEI helmets cover most of the back of the rider's head, and are required to provide protection for a specific area. Without proper coverage, the helmet does not pass certification testing. "Item of apparel" helmets have liner material only at the top of the head and partly down the side (with as much as two inches of unprotected gap) and comfort foam, which offers no protection, around the sweat band area. In many cases, bicycle helmets currently on the market offer a protection area which only covers the top of the head.

ASTM/SEI riding helmet manufacturers are visited periodically by a quality auditor who makes certain that all certified helmets meet the minimum standards. Only bicycle helmets made to ASTM F1447 have this same requirement, and bicycle helmet manufacturers are not required to have SEI certification by any federation or law,

ASTM/SEI helmets must be covered by liability insurance for as long as the helmet model is in use, even after it has been replaced by a new model. Only SEI certified bicycle helmets must carry similar coverage.

ASTM/SEI helmets are made in several different shapes and a variety of sizes, so that every rider can he properly fitted. Although some models come in a range of Small, Medium and Large, if none of these fits perfectly even with the addition of the sizing pads included with the helmets, the rider still has the option to buy another model helmet for his or her specific head size. Bicycle helmets do not offer this option.

The usual reasons for preferring a bicycle helmet to a riding helmet are:

1. My child already has a bicycle helmet, why should I buy another helmet?
2. Price
3. Price
4. Price

It is true that you buy a bicycle helmet for $11.00 and up in a discount store. Even discounted or on sale one can seldorn find an ASTM/SEI helmet for less than $40.00. So you can save $29.00 or even more by buying the bike helmet. But what have you given up in return?

1. Coverage area is generally not independently certified. Although the three U.S. bicycle standards show specific areas of the head which must he protected, only those made to ASTM F1447 (bicycle) and SEI Certified are tested in an outside laboratory to meet that standard. Not all manufacturers choose to have their products certified.

The Snell Foundation does its own internal certification and testing of helmets made to their standard. Unfortunately there are bicycle helmets on the market which say they pass Snell, but which do not contain an official Snell sticker showing that they have actually met the basic requirements.

Helmets made to the ANSI bicycle standard are all "self-certified." This means that a consumer takes the manufacturer's word that the product meets the standard. Consumer Reports in 1990 checked bicycle helmets, and found that 15% or more of the self-certified helmets met no current U.S. standard.

Because the organizations seriously concerned about riding safety have required in their rules that their members wear SEI certified helmets, all the helmets made to ASTM F1163 (equestrian) standards and sold in the U.S. are SEI Certified to pass all tests required in the standard.

2. Testing with a sharp anvil surface. All three bicycle standards drop test helmets on flat, hemispherical, or curbstone anvils. The equestrian hazard anvil has a deep and sharp design, meant to approximate the angle of a horseshoe or a jump standard edge. Helmet testing for both disciplines does not allow any hazard anvil to make contact with the testing head form.

Which do you think provides a tougher test, a sharp or a rounded or curbstone flattened anvil?

3. Insurance which covers equestrian activity. All three bicycle helmets specify that they are intended for bicycle use ONLY. This disclaimer means that in the case of a defective bicycle helmet used in horseback riding you will probably not be able to sue the manufacturer with any degree of success, since his insurance will not cover a riding activity

4. A design which will be accepted in riding competitions. Certain competitions require the use of particular types of headgear. You will not find bicycle helmets listed in horse competition rulebooks as recommended for riding competitions.

No helmet made can protect a rider from all possible injuries in every possible accident. Most riders capable of making a sensible decision can see the value in buying "state of the art" head protection made for their particular sport, and using it "EVERY TIME ....EVERY RIDE."

Perhaps the best argument to be made for the use of an ASTM/SEI riding helmet is to ask yourself if you, or someone you care about, has an $11.00 head. The choice is yours.

Drusilla E. Malavase, 2270 County Road 39 RD 2, Bloomfield NY 14469

Jaymin Patel, International Riding Helmets, Ltd., 205 Industrial Loop, Staten Island, NY 10309

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New Mexico Equestrian Safety Project Kicks Off "Wear a Helmet, Don't Horse Around"

New Mexico is one of six states targeted in a national program to encourage equestrian riders to wear safety approved helmets in response to serious injuries and tragic deaths related to horseback riding. Horseback riding has one of the highest injury rates of all sports. Nationally, in 1991- 1992, more than 145,000 people were treated in hospital emergency rooms for injuries related to horseback riding. Nearly twenty percent of these admissions were for head or brain injuries. 1992 data from the New Mexico University Hospital indicated that horse-related injuries were the second leading cause of childhood trauma admissions to the state's Level I Trauma Center. The New Mexico Department of Health decided to launch a statewide campaign to promote the use of approved equestrian helmets by 4-H Club riders. As part of the pilot project, a survey was conducted at the 1994 New Mexico State Fair to measure equestrian helmet safety awareness among New Mexicans. The findings for 1-20 year olds in this self-reported survey indicate:

35% have had a horse-related injury
40% always wear a helmet when riding

Of those not wearing a helmet,
40% would wear a helmet if required by law
35% would wear a helmet if required by their club
35% would wear a helmet because of safety concerns
24% would wear a helmet if their friends did

The survey also showed that 95% of the people who responded were aware that a fall or a kick from a horse could cause a traumatic brain injury. To close the gap between knowledge and safety behavior, the Traumatic Brain Injury/Spinal Cord Injury Prevention Committee developed materials to promote helmet use among 4-H and other riding clubs and will be offering a one day "Train-the-Trainers" work-shop for 4-H Club youth and adult leaders in the fall of 1995. Clubs who participate will receive a FREE approved equestrian helmet, FREE training materials, a FREE copy of the Washington State 4-H video entitled "Every Time, Every Ride" and a financial stipend to attend the workshop. A survey of 4-H Club members' attitudes, behavior, knowledge and their club policies will be conducted both before and after the workshop The New Mexico state 4-H Foundation was supportive of this effort to bring much needed safety information to their club members.

For more information, call

Nancy Pieters, Disability Prevention Program, (505) 827- 2423

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Hyperkalemic Periodic Paralysis: HyPP

Robert N. Oglesby, DVM

This article is provided by THE HORSEMAN'S ADVISOR. THE ADVISOR offers information and consultation to the horse owner and industry at the internet site: www/ Duplication or distribution of this article requires informing the author of its proposed use and credit to the author in its publication.


Why should the equestrian medical community he interested in Hyperkalemic Periodic Paralysis (HyPP) in horses? These horses have been reported to injure their riders and caregivers during their episodes of muscle weakness, spasms, trembling, falling, and sudden death.

A genetic problem in the "Impressive" line of Quarter Horses has surfaced in the past few years. The disease is characterized by recurring episodes of trembling and weakness. The problem can get sufficiently severe to cause collapse and death. The problems usually start in young, well-muscled horses beginning training, but this is quite variable. It has been estimated that approximately 30% of Impressive's descendants have the gene. The HyPP gene is the result of a mutation and has not been identified in other lines of horses as of early 1995.

History/Symptoms/Clinical Signs

There is usually a history of past attacks, though single episodes do occur. Muscle tremors usually progress to buckling knees, swaying, and staggering. There may also be signs of difficult breathing, sweating and colic. During severe episodes the horse may collapse and be unable to rise for several hours. Death can occur. The horse may sweat but does not seem to have pain. These attacks will last a few minutes to a few hours and usually resolve on their own.


There are several tests for this disease, but confirmation requires a DNA test for the defective gene. The University of California at Davis runs this test for thirty-five dollars. To acquire a test kit call (916)752-7416.

Why Does It Happen/Pathogenesis

HyPP is a inheritable condition of the Impressive lineage of Quarter Horses caused by a point mutation in the gene encoding the alpha-subunit of the skeletal muscle voltage-grated sodium channel. This defect in the sodium channels of the muscle cells causes the signs associated with HyPP. In HyPP these channels open repeatedly during a single depolarization. These channels normally regulate sodium entering the cells and are partially responsible for initiating muscle contraction. The fluid within the cells of the body contains very high levels of potassium compared to the fluid outside the cells and in HyPP the potassium leaks out the sodium channels. The source of the high levels of potassium in the blood is the persistently open channels allowing leakage out of the muscle cells. As the cell loses potassium and gains sodium, membrane potential decreases to the point of inactivity and muscular weakness is the result.

HyPP is Inherited from the parent

Understanding transmission of the disease from parents to offspring is straight forward. HyPP is an autosomal dominant trait and is not sex linked. Horses with this disease are one of genetic two types: Heterozygous (has one HyPP gene paired with one non-HyPP gene) or monozygous (has an HyPP paired with an HyPP gene).

1. If one parent is heterozygous, 50% of his (or her) young will have the gene and will be heterozygous.

2. If one parent is homozygous 100% of his young will have HyPP and be heterozygous.

3. If a heterozygous HyPP positive horse is bred with another heterozygous HyPP horse the chance of a heterozygous HyPP horse is 50% and the potential for the more serious homozygous HyPP horse occurs 25% of the time. There is a 25% chance that the off-spring will he normal.

4, If both parents are homozygous, all young will be homozygous for the HyPP gene.

It is hard to understand why some horses with the HyPP gene develop signs and others do not. Our physical make up is decided by our genes. For each of our physical traits we have two genes. Usually only one of the two genes determines our physical trait. This is the dominant gene. HyPP is a dominant gene, but it does not always result in clinical signs. An important concept to understand however is that if the horse has this gene there is a possibility he will pass it on even if he is not showing signs,


Treatment consists primarily of dextrose/calcium solutions:

1. 500 ml of 34% calcium gluconate and 500 ml 50% glucose added to 10 liters 0.9% NaCl will treat a 1200 pound horse

Other helpful treatment includes:

2. Furosemide 0.55mg/kg

3. NPH Insulin 0055 microgram/kg

4. 5% NaHCO3 solutions at 2,2 ml/kg.

Walking the horse early in the attack helps.


To prevent attacks a combination of diet, exercise and medication can help. A diet low in potassium is the first step. Both timothy hay and Bermuda grass hay are low in potassium. Plenty of roughage should be available. Dividing his concentrate into three or four feedings a day helps. The horse should have regular exercise which should be changed only with slow increase or decrease in the amount of activity The diuretic acetazolimide (2 mg/kg twice daily) will help maintain more normal potassium levels,

Should We Be Breeding or Riding These Horses?

Of course the answer is no. These horses have a potentially lethal genetic detect that has a 50% chance of passing to the offspring. These horses also represent a potential source of danger to their riders. The onset of weakness is not predictable or preventable so these horses have a significantly increased propensity to stumble. There will be some who may disagree with this appraisal. I know of no accidents related to HyPP disease, but before you dismiss this as idle speculation consider these questions:

1. How many people do you know who have been hurt from a horse that stumbled or tripped?

2. Would a HyPP horse be your choice of a mount for trail riding?

3. What is the Quarter Horse supposed to represent as a mount for horse riders and professionals?

Robert N. Oglesby, DVM
8262 Coldwater Road Stokesdale, NC 27357 FAX 910/632- 6668

Should an HyPP Horse Be Ridden?

Dr. Sharon Spier is associate professor, Department of Medicine and Epidemiology, University of California, Davis. She is chief of the Equine Field Service. She has been involved with research on hyperkalemic periodic paralysis since 1985. The INTERMOUNTAIN HORSE AND RIDER, January 1996, states:

"According to Dr, Spier's studies, the chance of a paralysis episode occurring while the horse is being ridden is unlikely. However, muscle spasms are unpredictable and can occur with only slight symptoms. Therefore, it is recommended that only experienced horsemen (those aware of symptoms and familiar with the horse's behavior) handle and ride affected horses."

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The National Jockey Injury Study

A survey was conducted to determine the type of injuries to jockeys and racing related health concerns. The questionnaire was completed by 706 professional jockeys actively competing at United States race tracks between July and October 1990 about injuries they had sustained in their careers. More than 1,700 injuries were reported. There were significant numbers of serious injuries which prevented the jockeys from riding for long periods. In 1976 the National Athletic Health Institute studied 20 jockeys to assess their cardiovascular endurance, upper and lower body strength, and flexibility. The results showed jockeys to be in better physical condition than professional football, baseball, basketball, and hockey players.

Fractures were the most common injury being reported by 64% of respondents. Fractures of the leg, shoulder and arm represented 65% of all fractures. For all fractures, the mean number of days missed riding was 91, with a median of 60 days. Pelvic/hip fractures resulted in the greatest amount of time lost riding (mean = 151); spine/back injuries (mean = 132) and leg fractures (mean = 120) also showed significant time lost to riding. The amount of time missed riding was greatest for abdominal/organ punctures, which were seen in 5% of the jockeys surveyed, and showed a mean time missed riding of >4 months.

Because the upper extremities and chest accounted for 53% of the fractures, there may be a role for flak jackets as a protective device for jockeys. Concussions were reported by 54 jockeys, a 13% incidence. This is a high rate of injury to the central nervous system, higher than in football or boxing. Such a high number of concussions suggests a possible role for more protective headgear for jockeys.

The retrospective study has several drawbacks. The injury data were self reported; the more time that had elapsed since the injury occurred, the greater the possibility that the recollection of the injury would be less accurate; the degree of medical accuracy of the information obtained may be questionable; information on the injuries sustained by jockeys who are currently permanently or temporarily disabled was not included in the survey. More concise yearly surveys of injuries to jockeys would give more accurate injury types and rates than a cumulative career injury report such at this one. A prospective analysis would be even more accurate.

A national jockey injury database should be developed whereby all injury data is prospectively filed in one central place and analyzed annually. A standard injury report form could be distributed to every racetrack in the country. Information could be gathered from the official scorer of the race, the injured jockey and medical data from the treating physician or hospital. In this way all appropriate information could be followed on every injury that occurs, and more specific recommendations could be made for making the horse-racing industry safer.

Press J.M. Davis, PD, Wiesner SI, Heinemann A et al: Clin J Sport Med 1995; (5) 4:236-40

(Summary Doris Bixby Hammett MD)

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Are Deer Warning Devices a Danger to Horses?

"Are deer warning devices a danger to horses?" the British Horse Society, Stoneleigh Park, Kenilworth, England, asked the American Medical Equestrian Association. These devices are made in the United States by several companies including Cobbs Manufacturing Company, 913 S.E. 11th Street, Des Moines, IA 50309, 515/ 282-0267 FAX 515/282-4534; Sav-a-Life, PO Box 1226, New York, NY, 10025 800-634=3337; and the "Game Warning System," 930 Pilgrim Road, Plymouth, WI ,53073, Sam Godsey; 414/892-2553.

The manufacturer information states that the "Deer Warning" is protection from dangerous collisions with deer, dogs and cats. The device attaches to the vehicle bumper, is removable for easy cleaning, and works like a whistle with sound at an average frequency of 17,210 (from 16,000 to 20,000 hertz) at a sound pressure level of 106 decibels at vehicle speeds of 30 MPH and above. These sounds cannot be heard by humans, but can be heard by animals which avoid the vehicle and reduce the chance of an accident by 80% according to the Cobbs Manufacturing Company. Vehicular collisions with deer and other animals (estimated to be over one million killed a day) cost the motorists, companies, and governmental departments millions of dollars resulting from vehicular damage, personal injury and death.

The question asked by the British Horse Society was that if animals respond to the high frequency sound, could this create havoc to horse riders on the road and to horses in adjoining fields?

Katherine A. Houpt, VMD, Ph.D., Diplomate, American College of Veterinary Bahaviorist, Professor of Physiology, College of Veterinary Medicine, Cornell University, stated that horses can hear 16 KHz and higher frequencies at higher decibel levels. She stated that in New York, many cars have deer whistles, but horses do not seem to shy or balk.

Drusilla Malavase, Chairman, ASTM Sub-Committee Equestrian Equipment, stated that her cars are equipped with deer warning whistles, but none of her horses have responded other than to look at the vehicle.

Cobb Manufacturer states that although they maintain a Safety First Hotline they have had no reports of accidents involving horse response to the deer warning. Sav-a-Deer stated they had no reports involving accidents involving horse response. The Game Warning System stated they had handled the system far 10 years and never had information relative to any danger to horses. Todd A. Stevenson, U.S. Consumer Product Safety Commission, stated that they had searched their files and did not find any documents or records relative to Deer Warning products.

Dr. Katherine Haupt stated that with proper support, Cornell could test horse response to the deer whistle. If our readers have experience involving horse reaction to field use of the deer whistle or know of clinical studies involving this devise, please contact the American Medical Equestrian Association.

Doris Bixby Hammett, MD
103 Surrey Road
Waynesville, NC, 28786

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Nevada State Emergency Medical Services
Incidents related to an animal being ridden or animal drawn vehicle

Injury          90  91  92  93  94  TOTAL  Sub   %OF

Total Injured
FRACTURE Skull 7 12 4 5 6 34 15.5% Spine 7 2 8 7 8 32 14.5% Ribs 2 8 4 4 6 24 10.9% Pelvis 0 1 5 3 6 15 6.8% Extremities 7 12 11 9 17 56 25.5% Total 23 35 32 28 43 161 73.2%

DISLOCATION (not shoulder) 0 0 3 0 0 3 1.4% Shoulder 0 0 0 0 1 1 0.5% Total 0 0 3 0 1 4 1.8%

INTERNAL INJURIES Intracranial w/o FX 17 20 10 18 27 92 41.8% Cranial Nerves 1 0 0 0 0 1 0.5% Spinal Cord w/o FX 1 0 1 0 1 3 1.4% Thoracic Injury 2 6 4 4 2 18 8.2% Abdominal 8 7 4 6 2 27 12.3% Total 29 33 19 28 32 141 64.1%

OPEN WOUNDS Head Neck&Trunk 7 7 1 6 5 26 11.8% Upper Extremity 1 0 1 1 0 3 1.4% Lower Extremity 0 0 0 0 1 1 0.5% Total 8 7 2 7 6 30 11.6%

SPRAINS & STRAINS Ankle and Foot 0 0 0 0 1 1 0.5% Back 0 2 2 2 7 13 5.9% Superficial 17 0 1 0 0 18 8.2% Contusion w/o Open Wound 16 11 10 11 20 68 30.9% Unspecified 1 1 0 2 1 5 2.3% Total 34 14 13 15 29 105 47.7% [A person could have more than one injury.]

GENDER Male 24 29 16 17 24 110 50.0% Female 21 16 20 22 30 109 49.5% Unknown 0 0 0 0 1 1 0.5% Total 45 45 36 39 55 220

AGE Average Age 30 34 34 32 31 43 years Under 17 11 11 5 8 12 47 21.4% 17 and Older 33 34 31 31 43 172 78.2% Unknown 1 0 0 0 0 1 Total 45 45 36 39 55 220

HOSPITALIZATION Ave Days 3.6 6 3.3 4 3 3.98 >1 day 22 18 21 20 19 100 45.5% >3 days 15 13 14 13 12 67 30.5% Fatalities 0 0 0 0 2 2 0.9% Total 37 31 35 33 33 169

INJURED Pedestrian 6 3 0 0 0 9 4.1% Rider 37 41 29 38 53 198 90.0% Occupant 0 1 6 0 0 7 3.2% Unspecified 2 0 1 1 2 6 2.7% Total 45 45 36 39 55 220

Al A. Cirelli, Jr..
Assistant Professor Equine Science
School of Veterinary Medicine
University of Nevada Reno
Mail Stop 202
Reno, NV 89557-0104


The Nevada horse community and professor Albert Cirelli, Jr are to be commended for following the state System Trauma Register of animals being ridden. Every state should have these figures available for the state horse community members for their information and for following injuries in horse activities and for observing trends occurring in the state.

These figures are not complete for, although pedestrians and occupants are listed, these are only incidental. Medical studies show that injuries and deaths occur with horses when driving, in stable management, grooming, vetting, farrier work and to bystanders. These can occur by kicking, crushing, biting, being thrown from the vehicle or running over the person on the ground.

Injuries to the head (skull fractures and intracranial injuries) total 57.3%. We have no knowledge whether the person was wearing headgear of any type or if wearing headgear was it ASTM standard SEI certified?

Spinal injuries make up 15.9% of those admitted to the trauma centers. This injury has received increased attention since the cervical spine injury to Christopher Reeve. Fractures followed by internal injuries make up the great majority of trauma admission injuries.

As is occurring nationwide, the percent of women with serious injuries in Nevada is increasing, now equaling that of men, The average age of those injured in the horse activities is increasing, This may relate to the fact that more of the horse community consists of older riders, or that younger riders are more aware of the steps needed for safety when riding such as wearing secured ASTM SEI protective headgear.

The horse community in every state should obtain and follow the reports of the state System Trauma Register of the injuries and deaths that are occurring in the horse activities.

Doris Bixby Hammett, MD
103 Surrey Road
Waynesville, NC 28786

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