Trained Neuromechanical Adaptations Associated with ACL Injury Prevention Programs. by Tyler ...

438 Pages·2011·6.97 MB·English

Trained Neuromechanical Adaptations Associated with ACL Injury Prevention
Programs.

by

Tyler N. Brown

A dissertation submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
(Kinesiology)
in The University of Michigan
2011

Doctoral Committee:

Associate Professor, Riann Palmieri-Smith, Co-Chair
Assistant Professor, Scott G. McLean, Co-Chair
Professor, Ronald F. Zernicke
Associate Professor, Richard E. Hughes
© Tyler N. Brown 2011
Acknowledgements

First and foremost, I would like to extend a heartfelt thank you to my advisors, Dr. Riann
Palmieri-Smith and Dr. Scott McLean. I am not sure any words I put on this page will do
justice the thanks and appreciation I owe you. I have gained considerable respect for both
of you during this process. I will be forever grateful for the encouragement, feedback and
guidance you have provided me throughout my time here at Michigan. I truly do
appreciate the direction you have provide me and cannot thank you enough for taking the
time to be my mentors. Thank You.

To the members of my dissertation committee, thank you. To Dr. Richard Hughes and
Dr. Ron Zernicke, I have tremendous respect for you both and I would like to extend a
sincere thank you for all of your knowledge and experience that helped make this
possible. I have truly learned a great deal from this experience and I hope to depart
Michigan with some of your wisdom.

Thank you lab members past and present. I appreciate your encouragement and support.
Without all your help this would not have been possible. I truly appreciate you pitching in
with a helping hand when I needed it. I hope I can be there to lend a helping hand when
you need it, too. Thank you.

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Mark and Priya, without you both I would have no results. I truly owe you a sincere
thank you for helping me out with Matlab code. You have saved me hours and hours of
frustration and for that I am forever grateful.

Thank you to all the undergraduate students who have come through the lab. There are
too many to name and I would not want to leave anyone out so I will not try to mention
everyone who deserves praise. I think you know who you are. Without your help I would
not have made it through this project. You were a bigger help than you can imagine,
thank you.

Finally, I would like to thank my family. Without your emotional and financial support
this would not have been possible. Thank you for the encouragement, understanding and
patience. I cannot say enough. Thank you and without you I would not have made it.

Thank you.

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TABLE OF CONTENTS

ACKNOWLEDGEMENTS ii
LIST OF FIGURES vi
LIST OF TABLES ix
LIST OF APPENDICES xi
ABSTRACT xii

CHAPTER
1. Introduction 1
2. Quadriceps activation patterns predict sagittal plane knee kinetics during unilateral
landings 9
3. Comparative training-induced lower limb joint biomechanical adaptations between
uni-lateral and bi-lateral landings 30
4. Comparative adaptations of lower limb biomechanics during uni-lateral and bi-lateral
landings after different neuromuscular-based ACL injury prevention protocols 49
5. Trained quadriceps and hamstrings activation changes predict modifications of hip and
knee biomechanics following an ACL injury prevention program 78
6. Discussion 107
7. Conclusion 118
iv
8. Recommendations for future work 124
9. Literature review 127

APPENDICES 153
REFERENCES 407

v
LIST OF FIGURES

FIGURES

Figure 2.1 Subjects will react to a random light stimulus and move in the appropriate
direction upon landing from a forward jump. 14
Figure 2.2 Marker set for movement analysis (A) and model for skeleton kinematics and
kinetics (B) of the right (contact) leg. 15
Figure 2.3 Mean (± SD) stance phase knee biomechanical patterns during the single-
legged landing maneuver. 21
Figure 2.4 Relation between peak proximal tibia anterior shear force and rectus femoris
pre-activity (A), and peak stance knee flexion moment with recuts femoris and vastus
lateralis pre-activity (B) during single-legged landings. 22
Figure 3.1 The weekly schedule for the six-week neuromuscular training program
consisting of exercises from four components (core strength and balance, plyometrics,
resistance and speed). 36
Figure 3.2 A plot comparing the mean Pre and Post peak stance knee flexion posture for
both unilateral and bilateral landings between the Trained and Control participants. 41
Figure 4.1 The weekly schedule for the six-week isolated component (CORE or PLYO)
training programs consisting of exercises from either core stability and balance, or
plyometric components. 56
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Figure 4.2 A plot comparing the mean Pre and Post peak stance knee flexion posture for
both unilateral and bilateral landings between the NM, CORE, PLYO and CON
participants. 62
Figure 4.3 A plot comparing the mean Pre and Post peak stance knee abduction moments
among the NM, CORE, PLYO and CON participants. 65
Figure 4.4 A plot comparing the mean Pre and Post peak stance hip flexion angle among
the NM, CORE, PLYO and CON participants. 66
Figure 4.5 A plot comparing the mean Pre and Post peak stance hip flexion moment
among the NM, CORE, PLYO and CON participants. 66
Figure 4.6 A plot comparing the mean Pre and Post peak stance hip adduction angle
among the NM, CORE, PLYO and CON participants. 67
Figure 4.7 A plot comparing the mean Pre and Post peak stance hip adduction moment
among the NM, CORE, PLYO and CON participants. 67
Figure 4.8 A plot comparing the mean Pre and Post peak stance knee flexion moment
among the NM, CORE, PLYO and CON participants. 68
Figure 4.9 A plot comparing the mean Pre and Post peak stance knee abduction angle
among the NM, CORE, PLYO and CON participants. 68
Figure 5.1 Mean (± SD) stance phase hip biomechanical patterns during the single-legged
landing maneuver at both the post and pre-training time points. 91
Figure 5.2 Mean (± SD) stance phase knee biomechanical patterns during the single-
legged landing maneuver at both the post and pre-training time points. 92
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Figure 5.3 Relation between pre-post change in lateral hamstrings pre-activity with peak
stance hip flexion moment (A) and peak anterior knee joint reaction force (B) during
single-legged landings for the NM group. 95
Figure 5.4 Relation between pre-post change in peak stance knee abduction angle with
VL:LH co-contraction ratio for the CORE group. 96
Figure 5.5 Relation between pre-post change in peak stance knee abduction angle with
vastus lateralis pre-activity for the CON group. 96
Figure 5.6 Relation between pre-post change in peak stance hip flexion moment with
rectus femoris pre-activity for the PLYO group. 97

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LIST OF TABLES

TABLES

Table 2.1 Average RMS activation (mean ± SD) of the dominant limb for the pre- and re-
activity phases of the single-legged landing maneuver 19
Table 2.2 Regression coefficients from the full stepwise regression models associating
pre-activity muscle activation variables with key peak stance (0%–50%) phase knee joint
biomechanical parameters 20
Table 3.1 Subject Characteristics 34
Table 3.2 Average Vertical Jump Height 40
Table 3.3 Peak Stance (0% - 50%) Phase Hip and Knee Rotations 41
Table 3.4 Initial Contact Hip and Knee Rotations 42
Table 4.1 Baseline Subject Characteristics 61
Table 5.1 Average change (post-training – pre-training) in RMS activation (mean ± SD)
of the dominant limb following neuromuscular training for the pre-activity phase of the
single-legged landing maneuver. 90
Table 5.2 Regression coefficients from the full stepwise regression models associating
pre-post changes in preparatory muscle activation variables with training changes in peak
stance (0%–50%) phase anterior knee joint reaction force. 93
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