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Leg Ergometer for Blood Flow Studies. Amy Weaver, Laura Bagley, Lacey Halfen, Deborah Yagow, Lein Ma BME 200/300 October 19, 2007. Client: William Schrage Dept. of Kinesiology Advisor: Wally Block Dept. of Biomedical Engineering. Overview. Research Facilitating Ergometer
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Leg Ergometer for Blood Flow Studies Amy Weaver, Laura Bagley, Lacey Halfen, Deborah Yagow, Lein Ma BME 200/300 October 19, 2007
Client: William Schrage Dept. of Kinesiology Advisor: Wally Block Dept. of Biomedical Engineering
Overview • Research Facilitating Ergometer • Blood Flow Research and Analysis • Existing Leg Ergometers • Quantifiable Client Specifications • Alternative Resistance Approaches • Improvements on last semester’s device • Monark exercise bicycle • Proposed Design: Servo motor with brake • Construction and Testing
Research Facilitating Ergometer • Device to facilitate blood flow analysis during exercise • Femoral artery is imaged using an ultrasound • Test subject will use the ergometer to maintain a kicking motion against a constant workload • Leg must passively return to original position
Blood Flow Research • Measure blood flow in femoral artery • Examine how smaller blood vessels regulate upstream (femoral) blood flow • Infuse drugs into the femoral artery to isolate blood pathways http://www.gehealthcare.com/usen/ultrasound/images/cmeadi_fig3_500.jpg
Significance of Research • Metabolic, neural, and mechanical influences on control of blood flow • Altered by age or disease • Cardiovascular disease associated with blood flow abnormality • Can exercise restore normal blood flow? • Drug companies can develop pills to mimic effects of exercise
Background: Existing Devices • Part of an exercise bike and a car seat • Rollerblade boot with the toe cut out • Device was unreliable, and had variable forces Altered Monark stationary bike in use at Mayo Clinic
Last Semester’s Prototype • Frame built from pipe • Car seat fastened to frame • Snowboard binding to connect foot to resistance • Bicycle components used as resistance
Client Specifications • Constant wattage (range 0-100 W) • Kick rate 30-60 KPM • Chair positioned 30º from vertical • Adjust for heights 5’4” to 6’4” • Flexible range of motion while kicking • 180˚ leg extension • Passive return to rest position
Client Specifications • Output to computer through A/D converter • Adjustable workload • Under $2,000 • Easily portable (with wheels) • Minimum lifespan of five years
Consistent Design Components • From Previous Device • Seat • Snowboard boot • Frame • New Additions • Ball joints • Lightweight pedal bar • Force transducer in pedal bar to determine kick rate
Updated Bike • Retain bike wheel from last semester • Improve seat attachment • Weld seat to ergometer frame • Improve wheel attachment • Weld bike frame to ergometer frame • Add side support bars • Remove excess parts • Handle bars
Modified Monark • Electric or friction brake models • Convenient data display for RPM, Power, etc. • $900-$7,000 • Utilize only the flywheel and braking device • Pedal bar attaches Monark pedal to boot http://www.robbinssports.com/sporting-goods-store/fitness-and-exercise-exercise-bikes-c-24_272.html
Proposed Design: Servo Motor • Crank arm connects pulley to pedal bar • Brake attached to pulley via belt • Servo motor to adjust magnetic brake force • Console used to electronically adjust motor settings • Kicking motion propels crank arm around
Future Work • Obtain parts for servo motor design • Order pedal bar sensor • Build attachments to frame • Perform client monitored trials with various subjects • Ensure passive leg return • Verify wattage consistency
References • Maximal Perfusion of Skeletal Muscle in Man (Per Andersen and Bengt Saltin) 1984 • Chi-hua Fitness Co., Ltd. http://www.chihua.com.tw/English/MAIN.htm • Joe Halfen, Director of Quality, Octane Fitness