Transcript Field Measurement of Running Impacts

Field Measurement
of Running Impacts
Team: Chelsea Wanta, Amanda Feest, Matt
Kudek, Nicole Daehn, Lindsey Carlson
BME 201
March 9, 2007
Client: Dr. Bryan Heiderscheit, PhD, PT
Advisor: Paul Thompson
Overview
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Problem Statement
Background
Design Requirements
Proposed Designs
Design Matrix
Future Work
Questions
Problem Statement
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Design a portable system to measure tibial
accelerations. This system would
incorporate the use of an accelerometer
and a data logger.
Background
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Tibial stress fractures
 One
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of the most serious running injuries
Tibia absorbs force of impact instead of muscle
Greater forces on tibia may increase risk of stress fracture
Knee contact angle also has an effect on severity of impact
Current Methods
Patient runs on a force plate in lab
 Accelerometer is directly connected to PC
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 Hard-wired
through room
This system requires extensive wiring
 Limited testing for different running
surfaces
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Design Requirements
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Portable system
Lightweight accelerometer worn on leg
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Data logger
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Uniaxial
Measures up to 40G peak acceleration
Sampling rate of 1,000-2,000 Hz
Multiple analog inputs
Supply power to accelerometer(s)
Design should not affect runner’s gait
Prototype completed for use this summer
Proposed Design #1: Wired Device
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Description
 Data
logger worn on belt
 Accelerometer wired to logger
 Data logger provides power to accelerometer
Proposed Design #1
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Pros
 Reliable
signal
 Only one power source needed
 Good design to evaluate feasibility of a portable
system
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Cons
 Wires
on leg may be bothersome
 Belt with logger may be bulky
Proposed Design #2: Wireless
Device
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Description
 Bluetooth
communication between
components
 Data logger worn on belt
 Self-powered accelerometer
Proposed Design #2
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Pros
 No
wires
 Potential to download directly to a PDA or watch
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Cons
 Signal
can be unreliable at times
 Increased weight of accelerometer
 Difficult to manufacture
 Belt with logger may be bulky
Proposed Design #3:
Microcomputer Device
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Description
 Entire device worn on leg
 Accelerometer attached to microcomputer
 Microcomputer analyzes/stores data
 Downloads later to a PC
 One power source for entire system
Accelerometer
Amplifier
Analog to Digital
Converter
Microcomputer
Proposed Design #3
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Pros
 Compact
device worn completely on leg
 Reliable signal
 One power source
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Cons
 Not
feasible within time constraints of course
 Requires advanced knowledge of circuits
 Unknown if device would alter runner’s gait
Design Matrix
Wired
Wireless
Microcomputer
Signal Reliability (40)
10
7
10
Feasibility (30)
10
6
3
Lightweight on leg (20)
9
7
6
Comfort (10)
6
7
8
Total (100)
94
61
69
Future Work
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Finalize purchase of data logger
 Decide
on an accelerometer
Order components
 Construct prototype
 Testing
 Make adjustments, if necessary
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Any Questions?
References
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http://www.tekgear.com/index.cfm?pageID=90&prodid=22
7&section=73&nodelist=1,73&function=viewproducts
www.sparkfun.com/commerce/product_info.php?products
_id=254
http://www.bluetooth.com/bluetooth/
http://www.pcb.com/searchresults.asp?searchcriteria=352
a24
http://www.mie-uk.com/datalogger/index.html