Background: 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

Two Research Questions 1. What are the neural, metabolic, and vascular signals controlling blood flow at rest and exercise? 2. How do conditions like aging and cardiovascular diseases (obesity, high blood pressure, etc) alter the regulation of blood flow?

Wider Implications 1. Understanding blood pressure control 2. Correlation with obesity, diabetics, and high blood pressure

Problem Statement  Test subject will use the ergometer to maintain a constant kicking motion  Leg must passively return to original position  Femoral artery is imaged using an ultrasound  Ergometer used to determine blood flow to the leg during exercise

Background: Existing Devices  Current device in use at Mayo Clinic Made of:  Exercise bike  Car seat  Rollerblade boot Unreliable, variable forces  Other types of ergometers Used in rehabilitation Exercise bikes Ellipticals

Design Requirements  Streamlined and compact  Minimum lifespan of five years  Easily portable  5’ long x 3’ wide maximum  Chair positioned at various angles from vertical  Chair ~3’ above ground  Adjust for people of heights 5’4” to 6’4”  Wattage (0-100 W) and kick rate (30-60 KPM) output to a laptop through an A/D converter

Design Requirements  Maintain a constant wattage throughout testing  Adjustable force between tests  Set up for right leg testing  Boot to attach to patient foot  Flexible range of motion for full leg extension while kicking  Passive return to rest position of the leg after kicking  Under $2,000

Design Progress:  Frame Iron plumbing pipes provide sturdy frame and adjustability  Seat Car bucket seat reclines and can be moved back and forth  Boot for foot Snowboard binding allows for multiple foot sizes  Wheels Allow for ergometer mobility

 Bike parts - temporary Clutch provides one-way motion Brakes provide variable force Brakes adjusted by client  Sensors Hanging scale to sense force prior to beginning of test  Hinges Hinges and bar to connect boot to bike pedals Design Progress (Cont.):

Testing Performed  Multiple test subjects Size, compatibility, kicking pattern  Ten minute test Strain, Heat of brakes  Variable force test Strain, Heat of brakes, device stability

Budget Frame…………………….....$110 Chair & Cover………………$55 Boot………………………….$50 Bike………………………….$90 Hardware……………………$30 Total…………………………$335

Future Work  Implement new friction device Multiple proposed designs  Build clutch housing Received clutch from Formsprag Clutch  Research and purchase appropriate sensors  Add handles for test subject comfort  Attach fold-out table for client comfort  Test and modify

Future Work: One Way Clutch  Allows rotation in only one direction  Engages friction device when locked  Rotates freely when leg is returning to original position extbook/DataFiles/Appendix-B/Appendix-B.html

Future Work: Drum Brake  Shoes push out against drum providing friction  Easily adjustable Disadvantages  Force varies with temperature  Brake pedals require maintenance brake.htm/printable

Future Work: Viscous Friction  Viscous friction for force against kick Two pieces of metal with liquid between  Force remains constant through minor temperature changes Disadvantages:  Unable to find a model which provides the necessary torque Rotating Axle mf1i.spring02/Viscosity.htm

References:  Maximal Perfusion of Skeletal Muscle in Man (Per Andersen and Bengt Saltin) 1984  ADCATS at Brigham Young University 1/Paper1-12_6.html  

Additional Thanks To:  Professor Frank Fronczak Department of Mechanical Engineering  Mike Travis – Formsprag Clutch  Yashpal Subedi  Paul Tutabelli – Taylor Devices