KULAS, ANTHONY S., Ph.D. Effects of Augmented Local Abdominal

158 Pages·2005·1.99 MB·English

KULAS, ANTHONY S., Ph.D. Effects of Augmented Local Abdominal Activation
Patterns on Lower Extremity Biomechanics During Landing in Males and Females.
(2005)
Directed by Dr. Randy J. Schmitz. 158pp.

This research assessed changes in lower extremity biomechanics as a result of
augmented local abdominal contractions during double leg landings. The study design
followed a two-day (control and intervention days) within subject model in which two
conditions on each day were compared, (control-control and control-experimental) with
between sex comparisons. Fifty subjects (25 males and 25 females) were activity
matched and represented a sample of healthy and recreationally active individuals.
A repeated measures ANOVA comparing control and experimental conditions on
the intervention day revealed that all subjects significantly increased local abdominal
activation during 150ms prior to landing. However, a 2 (sex) x 3 (muscle) x 2 (phase of
landing) repeated measures ANOVA demonstrated that only males maintained this
contraction during the 150ms time interval after landing. A repeated measures ANOVA
evaluating changes in leg spring stiffness (LSS) as a result of the augmented local
abdominal contraction showed a sex by condition interaction demonstrating that only
males experienced significant increases in LSS from control to experimental condition
while females demonstrated no significant changes. No significant differences by
condition were noted when assessing changes in ankle, knee, and hip energetics. The
evaluation of lower extremity total joint displacements across condition demonstrated
that males increased LSS through decreases in hip range of motion while females showed
no significant changes in hip range of motion but increased knee and ankle motion. From
these results we concluded that augmented local abdominal activation during a double leg
landing task increased LSS by decreasing hip range of motion in males.
EFFECTS OF AUGMENTED LOCAL ABDOMINAL ACTIVATION PATTERNS ON
LOWER EXTREMITY BIOMECHANICS DURING LANDING IN MALES AND
FEMALES

by

Anthony S. Kulas

A Dissertation Submitted to
the Faculty of The Graduate School at
The University of North Carolina at Greensboro
in Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy

Greensboro
2005

Approved by

Committee Chair
To my wife Julie,

Your love and support made this accomplishment possible.
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APPROVAL PAGE

This dissertation has been approved by the following committee of the Faculty of

The Graduate School at the University of North Carolina at Greensboro.

Committee Chair

Committee Members

Date of Acceptance by Committee

Date of Final Oral Examination
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ACKNOWLEDGMENTS

I wish to acknowledge the patience and motivation from my dissertation advisor,
Dr. Randy Schmitz and my entire dissertation committee Dr. Sandra J Shultz, Dr. Jolene
M Henning, Dr. David H Perrin, and Dr. Richard M Luecht.
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TABLE OF CONTENTS

Page

LIST OF TABLES............................................................................................................vii

LIST OF FIGURES.........................................................................................................viii

CHAPTER

I. INTRODUCTION .....................................................................................................1

Statement of the Problem ......................................................................................5
Objectives..............................................................................................................6
Assumptions & Delimitations................................................................................7
Limitations.............................................................................................................8
Operational Definitions..........................................................................................8

II. REVIEW OF THE LITERATURE .........................................................................10

Introduction .........................................................................................................10
Core Stabilization ................................................................................................10
Introduction ..................................................................................................10
Global versus Local Abdominal Function....................................................11
Transversus Abdominis Function.................................................................13
Abdominal Hollowing..................................................................................20
Clinical Evaluation of Abdominal Hollowing..............................................21
Lower Extremity Biomechanics in Double Leg Landings.................................27
Introduction...................................................................................................27
Inverse Dynamics Calculations.....................................................................28
Lower Extremity Joint Energetics................................................................29
Leg Spring Stiffness......................................................................................33
Inter-Relationships between Leg Spring Stiffness and Joint Energetics......34
Kinetic Chain Approach to Understanding Human Movement..........................37
Introduction...................................................................................................37
Biomechanical Performance Assessment.....................................................37
Postural Control............................................................................................40
Core Stabilization and Kinetic Chain Function............................................43
Summary.............................................................................................................46

III. METHODS...............................................................................................................48

Design.................................................................................................................48
Subjects...............................................................................................................49
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Instrumentation...................................................................................................49
Procedures...........................................................................................................50
Data Processing and Independent & Dependent Variable..................................55
Statistical Analyses.............................................................................................59

IV. RESULTS.................................................................................................................61

Abdominal Hollowing Performance...................................................................61
Leg Spring Stiffness............................................................................................64
Lower Extremity Energetics...............................................................................64

V. DISCUSSION...........................................................................................................69

Abdominal Activation Patterns between Sexes..................................................69
Influence of Increased Local Abdominal Activation on Lower Extremity
Biomechanics....................................................................................................74
Clinical Relevance of the Kinetic Chain for Injury Risk and Prevention...........81
Future Studies.....................................................................................................84
Conclusion..........................................................................................................87

REFERENCES .................................................................................................................88

APPENDIX A. LANDING ACTIVITY QUESTIONNAIRE ......................................101

APPENDIX B. SPSS OUTPUTS & SYNTAX FOR HYPOTHESIS #1 .....................102

APPENDIX C. SPSS OUTPUTS & SYNTAX FOR HYPOTHESIS #2......................104

APPENDIX D. SPSS OUTPUTS & SYNTAX FOR HYPOTHESIS #3 ....................110

APPENDIX E. SPSS OUTPUTS & SYNTAX FOR HYPOTHESIS #4......................115

APPENDIX F. SPSS OUTPUTS & SYNTAX FOR HYPOTHESIS #5 .....................119

APPENDIX G. POWER ANALYSIS TO ESTIMATE SAMPLE SIZE......................132

APPENDIX H. ACTIVITY MATCHING SPREADSHEET........................................133

APPENDIX I. IRB APPROVAL FORM.....................................................................134

APPENDIX J. CONSENT FORM...............................................................................135

APPENDIX K. DATA SETS........................................................................................138

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LIST OF TABLES

Page

Table 1 Recreational Levels and Activity Matching.....................................................49

Table 2 Reliability and Precision of Surface EMG during Abdominal Hollowing.......54

Table 3 Means +/- Standard Deviations for TrA-IO Preactivation Ratios....................62

Table 4 Means +/- Standard Deviations for Leg Spring Stiffness.................................64

Table 5 Average Powers Across Day, Joint, Landing Phase, and between Sex............68

Table 6 Means +/- Standard Deviations for TrA-IO Post-Impact Ratios......................72

Table 7 Estimated Marginal Means for Average Powers Across Day..........................81

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LIST OF FIGURES

Page

Figure 1 The Abdominal Hoop Mechanism (Adapted from McGill, 2002)................17

Figure 2 Abdominal Hollowing in Supine to Monitor Lumbar Pressure.....................21

Figure 3 Prone Quantification of Abdominal Hollowing.............................................22

Figure 4 Abdominal EMG Setup and Clinical Positions to Instruct AH.....................54

Figure 5 Changes in Abdominal EMG Ratios Across Muscle** & Phase in Males...63

Figure 6 Changes in Abdominal EMG Ratios Across Muscle** & Phase in
Females........................................................................................................63

Figure 7 Average Powers Across Sex, Joint, and Phase for Day 1..............................66

Figure 8 Average Powers Across Sex, Joint, and Phase for Day 2..............................67

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