MINOURA RDA Inter-Rim Ergo-10 / 50 Instruction manual
Please read this instructions carefully before use
(This figure is the Remote Control version)
Thank you for purchasing Minoura's Inter-Rim Ergo Trainer with RDA and Magturbo. With its unique rim-drive system, the RDA Inter-Rim Magturbo is our most sophisticated bicycle home trainer for both road and mountain bikes. Minoura has long been an innovator in stationary trainers, and our new Inter-Rim trainer continues that tradition. The Rim Drive Action (RDA) system has special drive pulleys that contact only the rim, avoiding wear and tear to the tire and any unpleasant noise. With the RDA system, training is smoother, more adjustable, and quieter, and you avoid the cost of replacing worndown tires. The RDA system can handle almost any bicycle with a wheel diameter of 26 to 28 inches and is the best trainer yet for mountain bikes.
Read all instructions carefully before use. Some assembly required. Keep the manual handy at all times. Lost instruction materials can be replaced through Minoura or your local dealer. Do NOT use trainer for any other purpose than instructed. The trainer is manufactured to precise standards. You may not disassemble or rebuild it. "Inter-Rim" and "RDA" are trademarks of Minoura and may not be copied.
Please obey warning signs.
ASSEMBLING YOUR MINOURA TRAINER
Couplings Hub-clamp handle Mag Unit Height Adjust Knob Mag Unit Remote Control Lever Drive roller Frame U-Leg Drive-pulley lever
Mag unit installation slot Assistant roller unit installation slot Rubber Foot Cap

(Fig. A)

Open the frame and U-Leg and place on level floor.
Prior to assembly of the Magturbo unit, locate the two bolts and two washers. Locate the left-side slot on the Minoura trainer. While placing the Magturbo unit at the desired position on the inside of the slot, attach it with bolts and washers by using the included hex wrench. (see Fig. B) After installing the Magturbo unit, put the Height Adjust Knob (maybe an option) through the hole on the pre-installed bracket on the left side slot, and then tighten it to the thread on the Magturbo support base. This optional Height Adjust Knob will help your adjustment of Magturbos height in order to fit the rubber roller properly to the rim side wall. (see Fig.C)

(Fig. B)

(Fig. C)
Mag unit must be assembled on the left side of RDA Trainer and the Assistant Roller Unit on the right. Do not mistake directions, see diagram for accurate placement. After deciding the height of the pulleys tighten handle securely to avoid damage to equipment and/or rider. (see Fig. D)

(Fig. D)

Handle with care! Damage may occur if Mag unit is dropped.
Install the assistant roller unit to the right side of the frame, using the same process as with the left-side Mag unit. Make sure the assembly is secure and accurate. (see Fig. E)
The Inter-Rim is foldable and portable without requiring future disassembly of the Magturbo unit and assistant roller unit. The Magturbo unit must be on the left side of the Inter-Rim Ergo's frame, and the assistant roller unit must be on the right side. Both drive pulleys must be adjusted so as not to touch the tire. You do not need to set this adjustment at this stage of the assembly --- you can adjust it later, before use. Once you have set the height of the pulleys, you must fix them firmly. If they are loose, they may break and/or damage your bicycle.

(Fig. E)

INSTALLING YOUR BICYCLE

(Fig. F)

Before installing your bicycle, rotate both hub-clamp handles counter-clockwise to create a wide clearance between the couplings. (see Fig. F) Place the bicycle's rear hub between the two couplings, making sure that the quick-release skewer (or hub nut) is not yet touching either couplings. Then rotate the hub-clamp handles clockwise to fix the rear hub. Tighten until securely fastened, but do not overtighten. During this attachment process, you should adjust the position of the rim with checking the Rim Center Position Indicator on the Assitant Roller. (see Fig. G) -4-

(Fig. G)

Once you have set the correct position of the rim for your bicycle, you can install or remove your bicycle by rotating only one hub-clamp handle. This feature saves time. The Left-side coupling has a cut-away section to accomodate the shaft of the quickrelease lever. You must align this coupling with the shaft of the QR. Failure to do so may cause the coupling to improperly support the bicycle.
The couplings are designed to acommodate a certain style of quick-release lever. If you use an incompatible quick-release lever, it may not be properly supported be the coupling --- so you must change your quick-release to the correct style in order to prevent accidents.
The yellow levers control the release and placement of the rollers to the rim. By adjusting these levers, you will see that the two rollers contact the rim sidewall with equal tension. If they are not resting on the rim properly, but on the tire, then you must re-adjust the height of the drive pulleys so that the roller contact is solely with the rim. (see Fig. H)

(Fig. H)

If the rollers are rubbing against or touching the tire, it may cause the tire to burst. Roller-to-rim contact ONLY! (see Fig. I)

(Fig. I)

Be careful not to pinch fingers in springs while adjusting. (see Fig. J) (Fig. J) -5-
To remove your bicycle from the trainer: First, push down both yellow levers, which releases the rollers and drive pulleys from the bicycle rim, and then rotate the hub-clamp counter-clockwise until loose, and pull out the bicycle. (see Fig. K) (Fig. K)

USING THE MAGTURBO UNIT

The Magturbo unit has seven different levels of load force, replicating actual riding resistance. The load settings range from high (H) to low (L) and can be adjusted via the yellow lever on the Magturbo unit. The rider may also adjust the load force by shifting up or down among his gears, depending on the level desired. We recommend that you start with a medium to low load force and gradually work up, increasing force as muscled warm up.
To decrease the load force, move the yellow lever on Mag unit toward the (L) symbol. The lowest selection is not zero load; there still be a small level of force. When your Mag unit is a remote control type, twist the lever on your handlebar toward the (L) symbol.

To increase the load force, move the yellow lever on the Mag unit toward the (H) symbol. When your Mag unit is a remote control type, twist the lever on your handlebar toward the (H) symbol. You must not be riding the Inter-Rim trainer when you are adjusting the yellow lever for load force. Make sure all parts have stopped spinning. Do not try to adjust the lever with your feet while riding.

OPTIONS

In 1998 Minoura is offering an option to the RDA Magturbo system called ICE (Interactive Cycling Experience) system. This computerized option will give the rider continuous automatic load changes according to preprogrammed software supplied by UltraCoach in California, U.S.A. This easy-to-install unit provides a more enjoyable and accurate training experience. -6-
REPLACING YOUR DRIVE ROLLERS
When you first start riding, the Inter-Rims rim rollers may be stiff and cause the rim to slip. But the rollers will soften after a few rotations and will impart the proper rim grip. The rubber rollers may melt or wear by heating from longtime use. The rim-drive rollers will eventually wear and need to be replaced. When you find that your load force has diminished altogether or that you feel some vibrations that cannot be avoided through minor adjustments, then it is time to invest in a roller replacement set, available from your Minoura dealer.
To remove: Apply a 10mm wrench to the nut behind the pulley while turning the bolt with a M4 hex wrenc h. (see Fig. L)
If you are changing the roller on the Mag unit (left) side, go to step 3. To change the roller on the assistant-roller-unit (right) side, pull back the pulley and remove the rubber roller.

(Fig. L)

To remove the pulley on the Magturbo unit (left) side, you must loosen the two bolts that are located on the surface of the Mag unit with a M4 hex wrench. Push the Mag unit in the direction of the drive roller to loosen the V-Belt and then pull out the pulley. (see Fig. M)

(Fig. M)

Do not remove the bolts that control the tension on the V-Belt. Drive pulley

Rubber roller

As you did with the right-side roller in step 2, pull out rubber roller from the pulley. (see Fig. N) Plastic shaft
Be sure to replace both rollers at the same time to prevent uneven wear to the rim and to ensure a more balanced ride. -7-

Under pulley cover

(Fig. N)
After replacing the rollers, you must fix the pulleys upper and lower covers firmly. On the Mag unit side, after applying the pulley you must pull the Mag unit to tension the V-Belt. Then, tighten the two bolts while holding the V-Belt in the proper tension. When you fix the upper and lower roller covers, you must make sure these covers are parallel. If the covers are not parallel, it may result in vibration that may loosen the rollers and cause an accident. (see Fig. O) (Fig. O)

MAINTENANCE AND SERVICE

If strange noises or vibration persist, discontinue use immediately and return to your Minoura dealer or place of purchase for assistance. You may also contact Minoura Co.,Ltd.: 1197-1 Godo, Anpachi, Gifu 503-2305 Japan, or contact to Minoura North American R&D Center at 1-510-739-1395. Always check for tightness of bolts and nuts before using. Check V-Belt and couplings for excessive wear or damage. Remove all oils and moisture from drive pulleys and other devices. Keep dry and out of weather.

NOTE ON DISPOSAL

To dispose of an old or broken trainer, please disassemble as much as possible and recycle properly. Do NOT dispose of trainer in trash. Harmful gas may occur if burned. Keep abandoned parts away from children.
Slope Level and Resistance
600W 500W 400W 300W 200W 100W 0W -100W

10km/h

15km/h

20km/h

25km/h

30km/h

35km/h

40km/h

LOAD LEVEL OF EACH LEVER POSITION
300 W 250 W 200 W 150 W 100 W 50 W 0W

0 km/h

5 km/h

10 km/h

15 km/h

20 km/h

25 km/h

30 km/h

35 km/h
The RDA Magturbo can simulate a maximum upward slope of 4 percent. These data were measured on official testing equipment at the Japan Bicycle Technical Center. They may very according to size of the bicycle and rim and weight of the rider.
EFFECTIVE TRAINING INSTRUCTIONS
Effective training requires some load resistance. Even in the minimum load setting, the Inter-Rim Ergo offers some resistance. A gradual increasing of the load force is better for your muscles and a more effective form of training. By manipulating the load force and your bicycle gears, you can get your preferred level of resistance. We reccomend that you consult a knowledgeable fitness trainer about your personal training program. Always stretch before riding the trainer, warm up when you begin riding, and cool down slowly when you are finishing your session. This will help to avoid injury to muscles and joints.

For best results, it is important to maintain a consistent cadence through any changes in load force.
Next page is a sample trainer workout for a rider who is using a mountain bike with the Inter-Rim Ergo trainer. This exact workout may not be suitable for everyone, but you can modify the gear ratio and load settings to suit your power and preference. If you need further guidance, please ask a professional for a personal training program. -9-

40 km/h

WORKOUT SAMPLE Front chainring* Middle Middle Middle Middle Middle Middle Middle Rear cog Cadense 28T 90 rpm 24T 21T 18T 16T 14T 21T 90 rpm 90 rpm 90 rpm 90 rpm 90 rpm 70 rpm
15 minutes 10 minutes 10 minutes 10 minutes 10 minutes 10 minutes 15 minutes
* You may shift to the outer ring, but the inner ring will not be effective for training.
NOTE ON HIGH SPEED TRAINING
This magnetic resistance device may be able to realize you such an impossible situation as you can run at over 35 MPH speed easily because your tire doesnt contact the earth, but only the rollers. As you know, in fact, there is no way when you ride on the road, but you can do it on this Inter-Rim Ergo trainer with lowest resistance load force and high gear ratio. And such a stupid high speed training may cause a problem on bearings and/or shaft. This magnetic resistance device is designed for usual training under 35 MPH (56 KPH) speed, so you should keep your training speed under the limit. If there is an awful noise or vibration from your magnetic resistance device during your training, please contact your purchased dealer or Minoura immediately.

- 10 -

REPLACEMENT PARTS
You can get the following replacement parts for your Inter-Rim trainer through your local dealer; ORDER #400-1240-00 DRIVE ROLLER (MAG UNIT SIDE) ORDER #400-1255-00 35mm DIAMETER RUBBER FOOT CAP
(This part is not compatible with 1998 or older model.)
ORDER #400-1241-00 ASSISTANT ROLLER (TENSION ROLLER SIDE)
ORDER #400-1243-00 COUPLING UNIT (REAR COG SIDE) ORDER #400-1244-00 COUPLING UNIT (QUICK-RELEASE SIDE)
ORDER #400-1242-00 TENSION ROLLER LEVER
ORDER #400-1246-00 HUB HANDLE
ORDER #400-1247-00 V-BELT (K-16)
ORDER #400-1245-00 MAG REMOTE CONTROL SHIFTER KIT

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RESOLUTION DIAGRAM
FOR MORE INFORMATION ON YOUR MINOURA TRAINER
MINOURA NORTH AMERICAN CENTER FOR RESEARCH, DEVELOPMENT AND MARKETING 37653 B Argyle Rd., Fremont, CA 94536 U.S.A. Phone 510-739-1395 / Fax 510-790-1108 E-mail : MinouraUSA@IBM.net MINOURA TECHNICAL & WARRANTY CENTER Toll Free 800-601-9592 MINOURA CO., LTD. 1197-1 Godo, Anpachi, Gifu 503-2305 JAPAN Phone +81 584-27-3131 / Fax +81 584-27-4258 E-mail: minoura@okbnet.or.jp http://www.minoura.co.jp MADE IN JAPAN

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports
This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports
This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports
HETA 2000-0305-2848 City of Long Beach Police Department Long Beach, California
Steven M. Schrader, Ph.D. Michael Breitenstein, B.S. Brian Lowe, Ph.D.

PREFACE

The Hazard Evaluations and Technical Assistance Branch (HETAB) of the National Institute for Occupational Safety and Health (NIOSH) conducts field investigations of possible health hazards in the workplace. These investigations are conducted under the authority of Section 20(a)(6) of the Occupational Safety and Health (OSHA) Act of 1970, 29 U.S.C. 669(a)(6) which authorizes the Secretary of Health and Human Services, following a written request from any employer or authorized representative of employees, to determine whether any substance normally found in the place of employment has potentially toxic effects in such concentrations as used or found. HETAB also provides, upon request, technical and consultative assistance to Federal, State, and local agencies; labor; industry; and other groups or individuals to control occupational health hazards and to prevent related trauma and disease. Mention of company names or products does not constitute endorsement by NIOSH.
ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT
This report was prepared by Steven M. Schrader, Ph.D. and Michael Breitenstein of Biomonitoring and Health Assessment Branch (BHAB) and Brian Lowe, Ph.D., Organizational Science and Human Factors Branch (OSHFB), Division of Applied Research and Technology (DART). Field assistance was provided by John Clark, Laboratory Technician, BHAB. Desktop publishing was performed by Nichole Herbert. Review and preparation for printing were performed by Penny Arthur. Copies of this report have been sent to employee and management representatives at the Long Beach Police Department and the OSHA Regional Office. This report is not copyrighted and may be freely reproduced. Single copies of this report will be available for a period of three years from the date of this report. To expedite your request, include a self-addressed mailing label along with your written request to: NIOSH Publications Office 4676 Columbia Parkway Cincinnati, Ohio 45226 800-356-4674 After this time, copies may be purchased from the National Technical Information Service (NTIS) at 5825 Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may be obtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall be posted by the employer in a prominent place accessible to the employees for a period of 30 calendar days.
Health Hazard Evaluation Report 2000-0305-2848 City of Long Beach Police Department Long Beach, California May 2001

SUMMARY

In May 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) from a representative of the International Association of Machinists and Aerospace Workers (IAM) Local 1930. The health concerns were genital numbness, sexual dysfunction, and feet problems in the Marine Bicycle Patrol, Long Beach Police Department, Long Beach, California. From July 10 to 22, 2000, NIOSH researchers visited the City of Long Beach, California, to evaluate the Marine Bicycle Patrol officers and the possible health effects associated with biking. Twenty-nine biking officers participated in at least part of the study. Five non-biking men from the Long Beach area were used as the comparison group. Fourteen of the fifteen (93%) bikers responding to questions on genital numbness indicated that at times they experienced numbness in their buttocks, scrotum, testicles, or penis during or after riding their bicycles. This numbness occurred after 10 minutes to 3 hours of riding and lasted from 5 minutes to 24 hours. Blood hormone levels and semen quality were normal in the officers providing samples. The male study participants were asked to wear a Rigiscan erection monitoring device for 2 nights. The number of sleep erections was not affected indicating the basic neurophysiology of erectile function was intact in biking officers. However, measures of erection quality were lower in the biking officers. The percent of the sleeping time a man had an erection was statistically reduced (p=0.0097) in the biking police (26.2%) compared to men (42.8%) not riding bicycles. As the measured pressure between the officer and the bicycle seat increased, the percent sleeping time the individual had an erection was decreased. Similarly, as the average number of hours per day an officer was on his bike and the average number of days a week the officer rode his bike increased, the percent sleeping time with an erection decreased. This study indicates that the pressure between the biking officer and the bicycle seat is related to numbness in the genitals and subclinical impairment of erectile function. Blood hormone levels and semen quality were normal in the officers providing samples. Recommendations to minimize or eliminate these specific problems reported by biking officers include minimizing pressure to the perineum from the bicycle seat nose. This can be achieved by taking rest periods off of the bicycle saddle and enuring proper bicycle fit. The police department is encouraged to investigate the feasibility of using bicycle seats without a nose or other extension. Keywords: SIC 9221 (Police Protection). Bicycle, bike, seat, erectile dysfunction

T ABLE OF CONTENTS

Preface. ii Acknowledgments and Availability of Report. ii Highlights of the NIOSH Health Hazard Evaluation. iii Summary. iv Introduction. 1 Background. 1 Methods. 1
Results. 3 Discussion. 3 Conclusions. 4 Recommendations. 4 References. 4

INTRODUCTION

In May 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) from a representative of the International Association of Machinists and Aerospace Workers (IAM) Local 1930. The IAM expressed two health concerns among the Marine Bicycle Patrol, Long Beach, California. The first concern was numbness and pain of male genitals associated with bicycle riding. The second was numbness and pain of the foot while pedaling. From July 10 to 22, 2000, NIOSH researchers visited the City of Long Beach, California, to evaluate these problems. Bicycle riding activities were monitored, personal seat and foot pressure measurements were measured, and erectile dysfunction and semen quality were assessed. Each study participant received a copy of their bicycle seat pressure measurements, erectile function measurements, hormone concentrations, and semen analyses results, along with a letter of explanation, in December 2000.
officers (approximately 15) represented by the POA were asked to participate in the study. While most participated in the pressure measurements, only two men represented by the POA participated in the reproductive health assessment. The Marine Patrol offices spent an average of six hours per day, five days per week, riding bicycles. The officers spend much of their time riding on wooded piers and ramps. Most of the riding time was slow riding, seated on the saddle. The officers often interacted with the public or conducted their work while seated and stationary on the bike, often with a hand on a pole or boat for balance. Less often, the bikers were observed in the high speed pedaling to get from one area to another quickly. Mountain bikes were supplied by the city for each officer. The newer bikes had full (front and rear) suspension systems to absorb the vibrations of the rough terrain. All of the officers had been supplied with a split bicycle seat (Serfas) in response to earlier complaints of genital numbness and sexual function problems. The officers indicated that they have had training in bicycling techniques. Each officer has his own bicycle and has adjusted it to his comfort.

BACKGROUND

In 1998, the Occupational Health Clinic for the City of Long Beach, California, reported that 15 of 23 biking policemen answered a self-administered questionnaire indicating they had some symptoms of genital numbness , groin pain, or impotence. There have been scientific reports indicating that biking may cause genital numbness and impotence. 1,2,3,4 T he Marine Patrol of the Long Beach Police Department is a bicycle unit of approximately 30 security officers who patrol the city-owned marinas. The primary patrol is on a bicycle. The city also employs a bicycle patrol which serves the more traditional role of bicycling policemen in the community. These officers have volunteered for this duty. The city bicycle police officers are represented by the Long Beach Police Officers Association (POA). The POA was included in the opening and closing conferences and biking

M ETHODS

All biking police officers were assigned by their supervisor to attend one of nine presentations by NIOSH staff describing the study. The presentations were held at a hotel meeting room and all officers were assigned a meeting time by their supervisor while they were on duty. After a 15 minute presentation the NIOSH project officer met with each officer in private to answer questions and request informed consent. All male officers were asked to participate in all aspects of the study. These included bike seat pressure measures, foot pressure measurements, foot exam, hormonal analysis, self-administered work/health questionnaire, self-administered sexual function questionnaire, and Rigiscan Rigidity Assessment System (device to evaluate
Health Hazard Evaluation Report No. 2000-0305-2848

Page 1

erectile function). For men who were interested in or concerned with their semen quality a mailin semen collection container was provided. Female bikers were asked to participate in the bike seat pressure measurements, foot pressure measurements, and the foot exam. The professional staff of a local hotel were asked to participate as a comparison group. A self-administered work and medical history questionnaire was distributed to each male study participant. The completed questionnaires were then mailed, by the participant, to NIOSH for data entry and analysis. Follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone, were measured, since endocrine insufficiency could affect reproductive and sexual function. The hormones were measured in a sample of venous blood collected from the participants arm.5 A semen analysis kit was available to interested participants if they were concerned about their fertility. This kit contained a collection jar and s hipping container. The men produced a semen sample by masturbation, at home, directly into the jar. The jar was placed into the shipping container and mailed to the contract laboratory for analysis. The analysis consisted of sperm count, sperm morphology (shape), and presence of white blood cells. Sexual function was assessed by the International Index of Erectile Function Questionnaire 6 and the Rigiscan Rigidity Assessment System.7 Again, the questionnaire was self-administered and returned by mail to NIOSH for data entry and analysis. The Rigiscan was used to assess erectile function during the normal sleep patterns of the participants. It is a computerized monitor worn on the leg, with two loops connected to the penis, one on the base the other on the tip, used to study the penis during sleep. Men have penile erections during their sleep, and the intent of the study was to compare the Marine Patrol and comparison group with respect to the number of erections and the percent of sleep time with an erection.8 For reliable results the participants

were asked not to ejaculate for one day before the test, not to drink coffee, tea, caffeinated soft drinks, or alcoholic beverages for 2 hours before bedtime, and not to take sedatives, tranquilizers, muscle relaxants, or sleeping pills the night of the test - all these have been linked with impaired sexual function. Scientists believe that the pressure between the biker and the bicycle seat obstructs the nerves and blood vessels in the perineum (area between anus and the scrotum). 9,10 The pressure exerted between the partic ipant and the bicycle seat was measured with a pressure assessment system (Force Sensitive Applications [FSA], Vista Medical LTD, Winnipeg, Canada). Each bicycle was placed into a stationary bicycle trainer (Magturbo Ergo, Minoura), then the pressure mat was aligned on the bike seat, and the officer mounted his bike and pedaled in a normal riding position and in a pursuit position. Each position was monitored for approximately 30 seconds. The officer dismounted his bike and the seat pressure mat was disconnected from the FAS computer system. A foot pressure mat was then attached. The foot pressure mat was inserted into the officers shoe. The officer again mounted his bike and pedaled in both normal and pursuit modes for approximately 30 seconds each. Cadence, intensity and resistance were self selected and not recorded The foot pressure measurements were stored on the computer system. A brief selfadministered questionnaire about possible foot pain and numbness, with drawings of the top and bottom of the feet to indicate the location of these concerns, was distributed to all study participants. Arrangements were made with a local foot specialist to examine the feet of these bikers. The foot specialist was only available one day and only 8 officers were able to be examined. Subsequently, a physical therapist with expertise in bicycle biomechanics and foot pain examined the pressure measurements and foot complaints. From these data he provided recommendations for minimizing foot pain and numbness. A convenience sample of 5 non-biking men was recruited from among city employees and hotel staff to serve as a comparison group. These men

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agreed to have the Rigiscan and hormone assessment. Bikers and non-bikers participating in the erectile function tests were paid for their time and inconvenience. Statistical analyses were conducted using SAS System for Windows (Version 8.01; Cary, North Carolina). Analysis of variance between the comparison group and the biking officers was calculated using the GLM procedure. Correlations between variables was calculated using Pearson correlation procedures.
sleep erections (non-biker 3.8 1.3; biker 4.6 1.7; p=0.38) was not affected indicating the basic neurophysiology of erectile function was intact in biking officers. However, measures of erection quality were lower in the biking officers. The percent of the sleeping time a man had an erection was statistically reduced (p=0.0097) in the biking police (26.2% 10.15%) compared to men (42.8% 19.00%) not riding bicycles. The percent sleeping time a man had an erection is negatively correlated (r=-0.43; p=0.07) with the pressure between the officer and the bicycle seat. (As seat pressure increases the erection time decreases). Similarly, the percent sleeping time a man had an erection is correlated (negative) with the average hours a police officer was on his bike (r=-0.45; p=0.05) and the average number of days a week the officer rode his bike (r=-0.58; p=0.01). The bicycle police officers sat on the saddle such that approximately 22% of the load (weight) supported by the saddle was distributed on the nose of the saddle and 78% of the weight on the saddle was distributed on the sit bone portion of the saddle. These percentages corresponded to average pressures of 2.3 1.7 and 2.9 1.0 pounds per square inch (psi) on the nose and sit bone portion of the saddle, respectively. Even though the nose supported a lower percentage of the load on the saddle (less than one quarter of the weight on the saddle is distributed on the nose), its smaller surface area acts to increase the localized pressure on the rider in this region. Scientists believe that pressure exerted on the nose of the saddle is most detrimental to the nerves and blood vessels in the perineum.1,2,3 Five of the eleven (45%) biking officers answering the questions about foot problems indicated that they had some foot pain and/or numbness. Measures of foot pressure were taken with inshoe pads. Measures were compartmentalized in six distinct zones. The foot was split into fore foot and rear foot sectors. The fore and rear foot sectors were then subdivided to represent distinct pressure zones of the foot. The average regional pressures were 14.1, 13.5, and 11.2 psi, for the lateral, mid-line, and medial regions of the fore-

RESULTS

Thirty-six biking officers from the Long Beach Police Department attended the presentation of the study across nine different sessions. Twentyeight officers had pressure measurements taken while riding their bikes. Seventeen officers provided blood samples for hormone analyses. Rigiscan measurements were conducted on 16 biking officers. The equipment malfunctioned and data was not recorded on 2 of these officers. Five biking officers provided semen samples; all sperm counts, WBC, and sperm morphologies were normal. Nineteen biking officers answered the Work and Medical Questionnaire and International Index of Erectile Function Questionnaire. Fourteen of the fifteen participants responding to questions about numbness (93%) indicated that at times they experience numbness in their buttocks, scrotum, testicles, or penis during or after riding their bicycles. The numbness usually occurred after an average of 1 hour and 41 minutes of riding (range 10 minutes to 3 hours) and lasted an average of 2 hours and 35 minutes (range 5 minutes to 24 hours). All blood hormone values were normal. The International Index of Erectile Function Questionnaire did not identify any men (biking officers or comparison group) with overt sexual dysfunction. The Rigiscan data did provide information on sleep erections. The number of

Page 3

foot and 5.9, 6.7, and 4.1 psi for the lateral, midline, and medial regions of the hind-foot.

DISCUSSION

The significant difference observed between the comparison group and the biking officers for the percent of sleep time a man has an erection would indicate that the biking offic ers have reduced erectile function. This interpretation is limited, however, by the self-selected nature of the comparison group. Because this measurement is also significantly correlated with average number of hours the biker rides and the amount of pressure on the bicycle, this increases the likelihood that the subclinical erectile impairment is related to the officers biking occupation. The observed differences are probably not due to the normal variation, because the number of sleep erections was not affected indicating the basic erectile function control by the brain was intact in biking officers. Our research team noticed that many officers conducted much of their work unnecessarily on the saddle. Many of the officers talked with the public, rested, and made general observations while still on the saddle. Many officers remain on the seat with their feet on the ground or the pedals and a hand supporting them against a pole, boat, or anything that would support them. This increases the amount of time that pressure is unnecessarily applied to the nerves and blood vessels of the perineum. The average saddle nose pressure measured in this study was approximately 2.3 psi. The findings of Rogers11 as cited by Armstrong12 suggest that ischemic tissue injury would occur at approximately 280 minutes (< 5 hours) of exposure to localized pressure of 2.3 psi. Some officers exhibited average saddle nose pressures that exceeded 4.64 psi during the seat pressure testing. This level of pressure corresponds to a tolerance time of less than 156 min (~ 2.5 hours). The ball of the foot and the heel bear most of the weight of the body while standing and walking. The shape and placement of the bicycle pedal

moves the weight (pressure) from these anatomical structures to the entire forefoot. The use of a hard-sole shoe redistributes the weight (pressure) from the entire forefoot back to the ball of the foot. This is similar to walking and thus a healthier posture. The hard sole shoe also allows the localization of the power of pedaling allowing optimal biking performance.

CONCLUSIONS

This study indicates that biking officers genital discomfort is related to pressure exerted by their bicycle seats. While according to the International Index of Erectile Function Questionnaire, none of the bikers studied were impotent, the decrement in erectile quality and the high percent of men complaining of genital numbness could be an indication of a developing reproductive health problem.

RECOMMENDATIONS

Although relevant published data are not available, the use of a bicycle seat without a nose would presumably result in less pressure on the perineum and the underlying nerves and blood vessels and thereby help to prevent these symptoms. Although a scientific study has not been conducted on the usefulness of their training, professional organizations of biking police officers (International Police Mountain Bike Association & Law Enforcement Bicycle Association) offer courses in bicycling techniques which may prove to be beneficial to biking officers. Biking officers should be encouraged to dismount the bike when they are not riding. Other work activities and rest breaks should not be conducted while straddling the bike seat. The proper adjustment of the bicycle seat and bicycle itself is very important.13 The pressure to the foot was primarily on the fore foot, but was not localized on the ball of the foot. Most officers were using soft soled shoes. Biking

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shoes would redistribute the pressure to ball of the foot which should bear most of the weight. The pedaling cadences used by the officers during testing appeared to be much slower than the recommended 80-100 revolutions per minute (rpms). Increasing the pedaling cadence with a lower pedal resistance can reduce foot numbness.13 Officers should use the gearing of the bikes to pedal at 80-100 rpms when practical.
Tumescence and Rigidity in Normal Men Using a Home Monitor. J Androl.10:492-497. 8. Levine LA, Carroll RA [1994]. Nocturnal Penile Tumescence and Rigidity in Men without Complaints of Erectile Dysfunction using a New Quantitative Analysis Software. J Urology 152:1103-1107. 9. Kerstein MD, Gould SA, French-Sherry E, Pirman C [1982]. Perineal Trauma and Vasculogenic Impotence. J Urology 127:57. 10. Broderick GA [1999]. Bicycle Seats and Penile Blood Flow: Does the Type of Saddle Matter? Abstracts of the American Urological Association. 11. Rogers J [1973]. Annual report of Rehabilitation Engineering Center. Rancho Los Amigos Hospital, University of Southern California, pp. 71-73. 12. Armstrong TJ [1985]. Mechanical considerations of skin in work. American Journal of Industrial Medicine, 8, 463-472. 13. Mellion MB [1991]. Common Cycling Injuries: Management and Prevention. Sports Medicine 11:52-70.

REFERENCES

1. Solomon S, Cappa KG [1987]. Impotence and Bicycling. Postgraduate Medicine 81:99-102.
2. Andersen KV, Bovim G [1997]. Impotence and Nerve Entrapment in Long Distance Amateur Cyclists. Act Neurol Scand 95:233-240. 3. Schwarzer U, Wiegand W, Bin-Saleh A, Lotzerick H, Kahrmann G, Klotz T, Engelmann U [1999]. Genital Numbness and Impotence Rate in Long Distance cyclists. Abstracts of the American Urological Association. 4. LaSalle MD, Wen C, Choi M, Salimpour P, Adelstein A, Gholami S, Krane RJ, Goldstein I [1999]. You Dont Have to Ride in the Tour de France: Erectile Dysfunction in 81 Consecutive Riders. Abstracts of the Americ an Urological Association. 5. Schrader SM, Turner TW, Breitenstein MJ, Simon SD [1993]. Measurement of Male Reproductive Hormones for Field Studies. JOM 35:574-576. 6. Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A [1997]. The International Index of Erectile Function (IIEF): A Multidimensional Scale for Assessment of Erectile Dysfunction. Urology 49:822-830. 7. Burris AS, Banks SM, Sherins RJ [1989]. Quantitative Assessment of Nocturnal Penile

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Highlights of the NIOSH Health Hazard Evaluation Evaluation of the City of Long Beach Police Department
NIOSH conducted a health hazard evaluation of genital numbness, sexual dysfunction, and feet problems in the Marine Bicycle Patrol, of the Long Beach Police Department in Long Beach, California.

What NIOSH Did

# # # # # # We surveyed officers about their work conditions and their health. We measured the pressure between the rider and the bicycle seat. We tested blood samples for reproductive hormones. We measured semen quality. We measured erectile function. We measured the pressure on the foot while pedaling. # # # #
What the City of Long Beach Police Departments Can Do
Consider purchasing bicycle seats which do not have a nose or other extension which may place excessive pressure on the perineum. Train each officer on proper riding techniques and proper dynamics between the rider and the bicycle. Consider providing a hard-sole mountain- or touring-style bicycling shoe. Consider utilizing (in-house or out-source) bicycle fit standards for bicyclists.

What NIOSH Found

# # # # 93% of the biking officers reported numbness while riding. Blood hormone levels were normal in the biking officers. The men who provided semen samples had normal semen. Officers erection quality was related to the number of hours he rode his bike and increased pressure between the rider and the bicycle seat was related to lower quality of the mans erection. # # # # # # #
What the City of Long Beach Police Officers Can Do
Dismount the bike when not riding. Dont straddle the bike seat during rest breaks or work activities not requiring sitting on the bike; instead dismount the bike. If pain or numbness occurs, get off the bike and walk the bike a few minutes until pain and numbness are relieved. Utilize gears that allow cadences near 90 rpms. Utilize frequent methods of pressure relief for feet. Perform regular/daily stretching excercises for calf, hamstrings, quadriceps, and gluteals. Know and record basic bic ycle measurements to ensure proper fit to the bicycle.

What To Do For More Information: We encourage you to read the full report. If you would like a copy, either ask your health and safety representative to make you a copy or call 1-513/841-4252 and ask for HETA Report # 2000-03052848
Highlights of the NIOSH Health Hazard Evaluation
For Information on Other Occupational Safety and Health Concerns Call NIOSH at: 180035NIOSH (3564674) or visit the NIOSH Web site at: www.cdc.gov/niosh
Delivering on the Nations promise: ! Safety and health at work for all people through research and prevention