PRINCIPAL COMPONENT ANALYSES OF JOINT ANGLE - QSpace

182 Pages·2010·3.09 MB·English

by  Erin Sadler

PRINCIPAL COMPONENT ANALYSES OF JOINT ANGLE CURVES TO EXAMINE
LIFTING TECHNIQUE

By

ERIN MARIE SADLER

A thesis submitted to the School of Kinesiology and Health Studies
in conformity with the requirements for
the degree of Master of Science

Queen‟s University
Kingston, Ontario, Canada
August, 2010

Copyright© Erin Marie Sadler, 2010
Abstract

The objectives of the present body of work were 1) to evaluate the Personal Lift-
Assist Device (PLAD) in terms of its effect on lifting technique, interjoint coordination,
and whether sex modulates these effects and 2) to explore the use of principal component
analysis (PCA) as a method to investigate lifting waveforms. Thirty participants (15M,
15F) completed a freestyle, symmetrical lifting protocol during which three-dimensional
kinematics of the ankle, knee, hip, and lumbar and thoracic spine were collected using a
two-camera Optotrak 3020 system. There were four testing conditions: a) with and b)
without wearing the PLAD; and c) 0% load and d) 10% of maximum back strength load.
All data were evaluated using PCA. In the first analysis, the relationship between the
PLAD and lifting technique under a loaded condition was explored. Results showed that
8 PCs were significantly different between the PLAD/No PLAD conditions yet there
were no significant effects of sex on any of the PCs. It was concluded that wearing the
PLAD encourages a lifting technique that is reflective of a squat lift, independent of sex.
In the second analysis, the PLAD‟s effect on interjoint coordination patterns under both
loaded and unloaded conditions was examined using the relative phase angle (RPA). It
was found that there were no significant differences between device, sex, or load
conditions on any of the PCs retained in the model. A novel approach to enhance
interpretability of PCs was developed during this study. Finally, when the PLAD was not
worn, male and female differences were further investigated under loaded and unloaded
conditions. It was determined that when the load is individualized to personal strength
characteristics, sex differences in lifting technique are negligible. This is a contradictory
finding from previous research. Overall, the major contributions of this research are:
ii
support for the use of the PLAD in industry; the recommendation that load be selected
based on individual strength characteristics for lifting research experimental design; the
use of PCA as a method to effectively evaluate lifting waveforms; and the development
of a novel approach to aid in the interpretation of principal components.

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Co-Authorship

This thesis contains material from submitted manuscripts (Chapter 3, 5, and Appendix
C). The authorship and intended authorship is as follows:

Chapter 3: Sadler, E.M., Graham, R.B., Stevenson, J.M. (2010). The personal lift-assist
device and lifting technique: A principal component analysis. Under revision in
Ergonomics (June, 2010).

Chapter 5: Sadler, E.M., Graham, R.B., Stevenson, J.M. (2010). Males, females and
lifting technique: A principal component analysis. Submitted to Theoretical Issues in
Ergonomics Science (June, 2010).

Appendix C: Sadler, E.M., Graham, R.B., Almosnino, S., Stevenson, J.M. (2010).
Principal component elimination to enhance the interpretability of principal components.
Submitted to Journal of Biomechanics (May, 2010).

iv
Acknowledgements

First, I would like to recognize the Natural Sciences and Engineering Research
Council (NSERC) for their financial support throughout my research endeavours. I am
very grateful for this funding as it has allowed me to pursue my academic interests
without financial barriers.
Next, I would also like to acknowledge my supervisor Dr. Joan Stevenson for
making this all possible. The past two years have been an incredible journey of discovery,
learning, and both professional and personal growth, and I could not have imagined a
better role model. Joan, the passion with which you pursue your research is inspiring, and
I feel so grateful to have been able to learn under your guidance. Beyond the positive
learning environment that you continuously foster, your kindness, generosity, and
constant support has made this experience so much more to me than simply an academic
pursuit.
I would also like to extend my deepest thanks to my lab mates over the past two
years, who quickly became my family, foundation, and support system. Thank you for the
laughs, the advice, the OBC experiences, and the countless memories. I would especially
like to acknowledge Ryan Graham for his friendship, mentorship, and endless help and
support. Ryan, the daily caffeine doses, rant sessions, Gordon/Harmony specials, and
lengthy data collections will be missed but fondly remembered. I owe you too many to
count.
Finally, I would like to thank my family and friends for keeping me sane
throughout this process, mostly because they never quite understood what I was doing
day in and day out at “the lab.” I cannot begin to thank them enough for their constant
love, support, and comic relief. Dad, thanks for being my rock; your early morning phone
calls and messages were the highlight of my days. Mom, you are so strong and brave, and
I continued to be inspired by you every day. Morgan, I am extremely privileged to have
such an incredible, talented, and supportive role model and older sister. And last but not
least Kieran, I am so proud of you and cannot wait to see what the future has in store for
you. I am the luckiest daughter and sister in the whole world to have the family that I do,
and without you all, none of this would have been possible.

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Table of Contents

Abstract ............................................................................................................................... ii
Co-Authorship .................................................................................................................... iv
Acknowledgements ............................................................................................................. v
Table of Contents .............................................................................................................. vii
List of Tables ...................................................................................................................... x
List of Figures .................................................................................................................... xi
Definition of Terms .......................................................................................................... xiv
Chapter 1 ............................................................................................................................. 1
General Introduction ....................................................................................................... 1
1.1 References ............................................................................................................. 7
Chapter 2 ........................................................................................................................... 10
Literature Review .......................................................................................................... 10
2.1 Musculoskeletal Disorders and Low Back Pain ................................................. 10
2.2 The Spine and Lifting ......................................................................................... 11
2.3 Lifting Technique: Squat and Stoop ................................................................... 13
2.4 The Personal Lift Assist Device ......................................................................... 17
2.5 Sex and Lifting Differences ................................................................................ 22
2.7 Interjoint Coordination and Lifting ..................................................................... 27
2.8 Principal Component Analysis ........................................................................... 31
2.9 References ........................................................................................................... 36
Chapter 3 ........................................................................................................................... 43
The Personal Lift-Assist Device and Lifting Technique: A Principal Component
Analysis ......................................................................................................................... 43
Abstract ..................................................................................................................... 43
3.1 Introduction ......................................................................................................... 44
3.2 Methods ............................................................................................................... 48
3.3 Results ................................................................................................................. 55
3.4 Discussion ........................................................................................................... 63
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3.5 Conclusion .......................................................................................................... 68
3.6 References ........................................................................................................... 70
Chapter 4 ........................................................................................................................... 74
Interjoint Coordination and the Personal Lift-Assist Device ........................................ 74
Abstract ..................................................................................................................... 74
4.1 Introduction ......................................................................................................... 75
4.2 Methods ............................................................................................................... 79
4.3 Results ................................................................................................................. 86
4.4 Discussion ........................................................................................................... 92
4.5 Conclusion .......................................................................................................... 98
4.6 References ......................................................................................................... 100
Chapter 5 ......................................................................................................................... 103
Males, Females and Lifting Technique: A Principal Component Analysis ................ 103
Abstract ................................................................................................................... 103
5.1 Introduction ....................................................................................................... 104
5.2 Methods ............................................................................................................. 108
5.3 Results ............................................................................................................... 112
5.4 Discussion ......................................................................................................... 117
5.5 Conclusion ........................................................................................................ 121
5.6 References ......................................................................................................... 123
Chapter 6 ......................................................................................................................... 126
General Discussion ..................................................................................................... 126
6.1 Overview of Findings ....................................................................................... 126
6.2 Limitations ........................................................................................................ 129
6.3 Major Contributions .......................................................................................... 131
6.4 Future Directions .............................................................................................. 133
6.5 References ......................................................................................................... 135
Appendix A ..................................................................................................................... 136
Ethics Approval .......................................................................................................... 136
Appendix B ..................................................................................................................... 138
Ethics Letter of Information and Consent ................................................................... 138
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Appendix C ..................................................................................................................... 144
Principal Component Elimination to Enhance the Interpretability of Principal
Components ................................................................................................................ 144
Abstract ................................................................................................................... 144
C.1. Introduction ..................................................................................................... 145
C.2. Method ............................................................................................................ 146
C.3. Results and Discussion .................................................................................... 148
C.4. Conclusion ....................................................................................................... 152
C.5 References ........................................................................................................ 153
Appendix D ..................................................................................................................... 155
Euler Angles – Method ............................................................................................... 155
Appendix D References .......................................................................................... 160
Appendix E ..................................................................................................................... 161
Power Analysis ........................................................................................................... 161
Appendix E References ........................................................................................... 162
Appendix F ...................................................................................................................... 163
Raw Curve Data .......................................................................................................... 163

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List of Tables

Chapter 2
Literature Review

Table 2.1. Data matrix (X) used as the input to PRINCOMP...........................................33

Chapter 3
The Personal Lift-Assist Device and Lifting Technique: A Principal Component
Analysis
Table 3.1. Summary of the principal component models for all joints in three axes and p
values for PC differences between device (PLAD/No PLAD) and sex (male/female)
conditions...........................................................................................................................56

Chapter 4
Interjoint Coordination and the Personal Lift-Assist Device

Table 4.1. Summary of the principal component models for hip-knee and lumbar spine-
hip interjoint coordination and p values for PC score differences between PLAD and No
PLAD (device) and load conditions...................................................................................87

Chapter 5
Males, Females and Lifting Technique: A Principal Component Analysis

Table 5.1. Summary of the principal component models for all joints in three axes and p
values for PC score differences between sex (male/female) and load (0%/10%)...........114

x