Transcript Biofeedback System for Improved Athletic Training

ECE-498
Matt Statton
Advisor: Professor Hanson

Goals of athletic training
◦ Muscle hypertrophy through stimulation
 Muscle fatigue during a specified repetition range
 Maximum motor unit recruitment inducing muscle
hypertrophy

Benefits of effective training
◦ Increased results
◦ Injury prevention

Many people do not know how to properly
fatigue their muscles
◦ Personal trainers

How it works
◦ Raises awareness of unconscious physiological
activities
◦ Control
◦ Adjustment

Uses
◦ Anxiety and stress
◦ Hypertension
◦ ADHD


Electrical signals produced by muscles can be
used as an indicator of muscle fatigue
Giving users the ability to recognize their
level of muscle fatigue will lead to improved
athletic training
◦ Maximizing muscle fatigue
◦ Decreasing injury




Measure electrical signals from muscles
Analyze signal to determine level of muscle
fatigue
Determine threshold at which muscle fatigue
occurs
Provide feedback response to user

Measure electrical signals from muscles
◦ Electromyography
 Intramuscular vs. surface electromyography
 Cost effectiveness
 Measurement accuracy
Figure 1: Electromyogram from
http://www.dataq.com/images/article_images/emg1.jpg

Measure electrical signals from muscles
◦ Electromyography

Analyze signal to determine level of muscle
fatigue
◦ Analog-to-digital conversion
◦ Measure absolute and relative maximum
amplitudes of signal


Determine threshold at which muscle fatigue
occurs
Provide feedback response to user

Important components
◦ MAX666CPA Voltage
Regulator
◦ LT1494 operational
amplifier, A = 1
 Provides virtual ground at
Vcc/2
◦ INA106 differential
amplifier, A = 10
Figure 2: Electromyograph circuit based on circuit
diagram from
http://instruct1.cit.cornell.edu/courses/ee476/Final
Projects/s2005/bsm24_ajg47/website/website/inde
x.htm
 High common-mode rejection
ratio


LPKF ProtoMat C20S Circuit Board Plotter
Figure 3: LPKF Circuit Board Plotter from
http://www.lpkf.com/_images/757-lpkfprotomat-h100.jpg
Figure 4: EagleCAD schematic of electromyograph
circuit
Figure 5: EagleCAD board file created from
schematic
Figure 6: CircuitCam circuit board diagram
Figure 7: BoardMaster circuit board diagram
Figure 8: Front of printed circuit board
Figure 9: Back of printed circuit board



Analyze signal to determine level of muscle
fatigue
Determine threshold at which muscle fatigue
occurs
Provide feedback response to user

Silicon Labs C8051F020 microcontroller
◦ On-board analog-to-digital converter
 ADC0 = 12-bit
 ADC1 = 8-bit
◦ Programmable in C
Figure 10: Flow chart of electromyograph signal analysis program
Figure 11: Contraction and relaxation of muscles of the upper arm
from http://www.zoodu.com/uploads/images/2006-0810/vlt9QAl2A5.jpg
Electromyogram of Fully Contracted Muscle
Electromyogram of Relaxed Muscle
2.505
2.7
2.5
2.65
2.495
2.6
2.49
Voltage (V)
Voltage (V)
2.55
2.485
2.48
2.5
2.45
2.475
2.4
2.47
2.35
2.465
2.46
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Time (s)
0.4
0.6
0.8
1
Figure 12: Electromyogram of relaxed biceps
muscle (Range = 30 mV)
2.3
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Time (s)
0.4
0.6
0.8
Figure 13: Electromyogram of fully
contracted and relaxed biceps muscle
(Range = 250 mV)
1
Electromyogram of Slightly Contracted Muscle
Electromyogram of Fully Contracted and Slightly Contracted Muscle
2.6
2.65
2.6
2.55
2.5
Voltage (V)
Voltage (V)
2.55
2.45
2.5
2.45
2.4
2.4
2.35
2.35
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Time (s)
0.4
0.6
0.8
Figure 14: Electromyogram of slightly
contracted and relaxed biceps muscle
(Range = 130 mV)
1
2.3
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Time (s)
0.4
0.6
0.8
Figure 15: Electromyogram of fully
contracted, slightly contracted, and
relaxed biceps muscle
1
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Signal processing
More sophisticated user interface
◦
◦
◦
◦
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LCD screen
Buttons
Threshold calibration
Low battery indicator
Electrode leadwire connectors
◦ FDA regulations
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

The 8051 microcontroller is not yet
accurately measuring absolute and relative
maximum amplitudes of the signal
Electrical signals were successfully measured
using surface electromyography
Continuing work will be done to successfully
analyze the signal and provide users a
feedback response based on muscle fatigue

Professor Hanson

Professor Hedrick

Ben Bunes
Association for Applied Psychophysiology and Biofeedback. 4 June 2008
<http://www.aapb.org/i4a/pages/index.cfm?pageid=1>.
Gariety, Arthur and Madoff, Benjamin. ECE 476 Final Project: Wireless Electromyograph. 13
November 2008
<http://instruct1.cit.cornell.edu/Courses/ee476/FinalProjects/s2005/bsm24_ajg47/we
bsite/website/index.html>.
U.S. National Library of Medicine, National Institutes of Health. Electromyography. 4 June
2008 <http://www.nlm.nih.gov/medlineplus/ency/article/003929.htm>.
http://www.dataq.com/images/article_images/emg1.jpg
http://www.lpkf.com/_images/757-lpkf-protomat-h100.jpg
http://www.winning.co.za/images/exImage6.jpg
http://www.zoodu.com/uploads/images/2006-08-10/vlt9QAl2A5.jpg