The Assessment of Lower Back Mechanical Behavior and Spinal Loads in Veterans With Non-specific Low Back Pain: a Feasibility Study
Conditions: Chronic Low Back Pain
Sponsor: VA Office of Research and Development

Principal Investigator/Study Chair: Babak Bazrgari 
The assessment of lower back mechanical behavior and spinal loads in veterans with 
non-specific low back pain: a feasibility study (Protocol # TBD) 
Funding Agency: Veteran Health Administration 
 [July 14th, 2022] 
 
 
Abstract 
Low back pain (LBP) is strongly associated with opioid consumption among 
veterans, and improved clinical management of LBP is likely to reduce reliance 
on opioid among veterans. Up to 60% of patients with an acute episode of non-
specific LBP experience either symptom persistence or symptom relapse within 
one year. This is likely an indication of a failure in addressing the underlying 
mechanisms of pain or initiation of a new etiology; both may stem from a 
mismatch between patients and treatments. The overall goal of our research is to 
develop, validate and implement measures that are relevant to known 
mechanisms of LBP, which can then be used to holistically gauge the health 
status of patients’ lower backs beyond self-reporting of symptoms. More accurate 
measurements will help better match of patients with existing treatments or 
development of more effective new treatments. The specific objective of this 
study is to generate evidence in support of the feasibility of our methods for 1) 
the evaluation of relative contribution of lower back tissues to spinal loads, and 2) 
the investigation of the resultant spinal loads in veterans with non-specific LBP. 
We have developed a powerful set of tools for the comprehensive assessment of 
spinal loads and lower back mechanical behavior (MB), that will enable us to 
examine the existence or development of abnormalities in spinal loads and lower 
back MB in three groups of veterans with different experiences with non-specific 
LBP. These groups will include 1) veterans with chronic, non-specific LBP and 
high level of disability (n=18), 2) veterans with chronic, non-specific LBP and low 
level of disability (n=18), 3) asymptomatic veterans without a recent history of 
non-specific LBP (n=18; serving as control group). Successful completion of this 
feasibility project will pave the way for future studies (merit grant applications) 
that will verify the role of abnormalities in lower back MB and spinal loads in the 
clinical presentation of LBP. Such an understanding has the potential to help the 
affected veterans with disabling non-specific LBP. Specifically, measures of 
lower back MB and spinal loads can be used not only to identify veterans with 
mechanical abnormalities in their lower back who are likely to experience LBP in 
the future, but also to guide novel integrated physical and psychological 
preventative treatments aimed at improved lower back mechanics. Ultimately, the 
goal and resultant improvement in clinical outcomes of treatment for non-specific 

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LBP is to diminish reliance on opioids for the symptom management of 
particularly veterans with chronic LBP. 
 
 
List of Abbreviations 
Abaqus/CAE 
A finite element software 
CBOC 
community-based outpatient clinic 
cm 
centimeter 
Co-I 
Co-Investigator 
DMAP 
Data management and access plan 
EMG 
Electromyography 
FE 
Finite element 
Fig 
Figure 
Hz 
Hertz 
ICC 
Intra class correlation 
ID 
Identification  
IRB 
Institutional Review Board 
Kollmorgen, AKM53K 
A servomotor model 
KY 
Kentucky 
L4, L5 
4th and 5th lumbar vertebrae 
LBP 
Low back pain 
Matlab 
A computational software 
MB 
Mechanical behavior 
n 
Number of participants 
Natick, MA 
Natick, Massachusetts 
Optex FA 
A laser sensor model 
PI 
Principal Investigator 
PROMIS 
patient-reported outcomes measurement information system 
Providence, RI 
Providence, Rhode Island 
Radford, VA 
Radord, Virginia 
RFA 
Request for application 

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RMDQ 
Roland-Morris Disability Questionnaire 
S1 
1st sacrum vertebra 
Scottsdale, AZ 
Scottsdale, Arizona 
SL 
Spinal load 
VA 
Veterans administration  
VAMC 
Veterans administration Medical Center 
Xsens MTW 
A motion sensor model 

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Contents 
Protocol Title: ............................................................................................................................. 5 
1.0 
Study Personnel .............................................................................................................. 5 
2.0 
Introduction ..................................................................................................................... 5 
3.0 
Objectives ....................................................................................................................... 7 
4.0 
Resources and Personnel ............................................................................................... 9 
5.0 
Study Procedures ...........................................................................................................10 
5.1 Study Design ...................................................................................................................10 
5.2 Recruitment Methods.......................................................................................................12 
5.3 Informed Consent Procedures .........................................................................................13 
5.4 Inclusion/Exclusion Criteria ..............................................................................................14 
5.5 Study Evaluations ............................................................................................................15 
5.6 Data Analysis ..................................................................................................................18 
5.7 Withdrawal of Subjects ....................................................................................................19 
6.0 
Reporting ........................................................................................................................20 
7.0 
Privacy and Confidentiality .............................................................................................20 
8.0 
Communication Plan ......................................................................................................21 
9.0 
References ...................................................................................................................21 
 

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Protocol Title:  The assessment of lower back mechanical behavior and spinal 
loads in veterans with non-specific low back pain: a feasibility study 
 
1.0 
Study Personnel 
• Provide name, contact information, and affiliations/employee status for 
Study Investigators and research staff: (e.g. John Smith, Principal 
Investigator, john.smith@va.gov. , Part Time 5/8)  
 
Principal Investigator: Babak Bazrgari, babak.bazrgari@uky.edu, VA part time 5/8 
Co-Investigators: Theresa Wolfe, theresa.wolfe@va.gov, VA full time 
Coordinator: N/A 
Research Assistant/Staff: Clare Tyler, cety222@g.uky.edu, VA WOC 
Research Assistant/Staff: Taylor Young, tryo227@g.uky.edu, VA WOC 
Research Assistant/Staff: Allison V King, allison.king1@va.gov, VA full time 
Research Assistant/Staff: Evan M Brown, evan.brown@va.gov, VA full time 
Research Assistant/Staff: Amy C Pohle, amy.pohle@va.gov, VA full time 
Research Assistant/Staff: Elizabeth Salt, elizabeth.salt@uky.edu, VA WOC 
Research Assistant/Staff: Vanessa Ramirez, vanessa.ramirez@uky.edu,  VA WOC 
Collaborators: TBD 
2.0 
Introduction 
• Provide scientific background and rationale for study.   
• Include summary of gaps in current knowledge, relevant data, and how 
the study will add to existing knowledge.   
• Include rationale for including or excluding certain populations – in 
particular vulnerable populations. 
Low back pain (LBP) is a significant human health disorder affecting up to 18% of the world 
population at any given time.1-3 In response to a recent national survey, 33% of veterans versus 
28% of non-veterans reported an episode of significant LBP in the prior three months.4 Chronic 

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LBP, the leading cause of disability globally,5 reduces quality of life6 and forces older workers to 
retire prematurely.7  Adding to the problem, highly addictive opioids are the most commonly 
used prescription pain medication among patients with chronic LBP in the U.S., both for 
veterans8-10 and non-veterans,11 and more than half of regular opioid users report LBP.12 Thus, 
LBP is a major economic and medical burden on patients and the Veterans Health 
Administration system. 
Symptom persistence or relapse is prevalent in patients with non-specific LBP, with two 
out of three patients experiencing these symptoms during the year following an episode 
of non-chronic LBP.13-16 Such an unsatisfactory clinical outcome for non-specific LBP is 
likely an indication of an unaddressed or newly developed etiology. While identification 
of the exact root cause(s) of LBP in these patients will be an important research 
challenge for years, there are measures that have relevance to some specific causal 
sources of LBP. These measures can be used for the clinical management of LBP to 
holistically gauge the health status of patients’ lower back more accurately than from the 
symptom reports alone. One such group of measures relates to the “spinal loads” 
experienced in daily life. Despite considerable controversies,17-21 there is strong 
evidence in the literature to support the plausibility of a causal relationship between 
spinal loads and LBP. For instance, the association of measures of spinal loads (e.g., 
net moment at the lower back), and the incidence and prevalence of LBP have been 
widely reported.22-26 Further, recent systematic reviews and meta-analyses have 
provided consistent evidence in support of a prospective association between spinal 
loads and LBP.27-29 Finally, animal and human cadaver studies have demonstrated how 
spinal loads occurring in daily life can activate nociceptor and initiate the inflammatory 
response, with or without injuries in spinal tissues.30-32 Therefore, there is an important 
research need for determination of whether measures of spinal loads can be integrated 
in clinical assessment of patients with non-specific LBP, and to help eliminate the risk of 
symptom relapse or persistence. Improved and objective assessment of patients’ lower 
back will enable clinicians to better match patients with treatments or develop more 
personalized novel treatments which will ultimately help improve the clinical outcomes of 
treatments offered for LBP. 
In this application, forces and deformations experienced in spinal tissues are referred to 
as spinal loads, and are the result of the active and passive mechanical responses of 
lower back tissues (i.e., internal forces) to the physical demand of an activity (i.e., 
external forces), in order to assure spinal equilibrium and stability.33-35 When performing 
a physical activity, active (motor or sensory) responses of lower back tissues to the 
activity demand determine the trunk and pelvic motions. The resultant trunk and pelvic 
motions in turn determine lumbar posture and passive tissue contribution (due to 
deformation) to spine equilibrium and stability. Therefore, alterations in active and 
passive aspects of lower back MB, along with changes in the way a physical activity is 
performed, alter spine equilibrium and stability, and thus ultimately the spinal loads. 
There is a large body of literature, including some from our laboratory, concerning the 
differences in the way a physical activity is performed between individuals with healthy backs, 
and those with acute/sub-acute/chronic or experimentally-induced LBP.36-41 Despite some 
discrepancies, that are likely driven by the heterogeneity of population with non-specific LBP, 
abnormalities like larger pelvic contribution to trunk motion, more in-phase and less variable 
lumbo-pelvic coordination during trunk forward bending and backward return, have been widely 
reported in patients with non-specific LBP.36-41 A large contribution of pelvis to trunk motion 
during forward bending has been suggested to be associated with higher spinal loads.42 It has 
been further shown that abnormalities in trunk and pelvic motions, observed in patients with 
non-specific LBP, linger beyond pain alleviation.43-45 Consistently, similar abnormalities in trunk 

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and pelvic motions have been reported in individuals with a history of LBP.46, 47 Individuals with 
LBP also demonstrate abnormalities in trunk and pelvic motions during activities of daily living 
like walking48, 49 and sit-to-stand.50, 51 Moreover, correlations between psychological factors and 
differences in trunk and pelvic motions among LBP patients have also been reported.45, 52 In this 
project, we will investigate whether these differences in the way a physical activity is performed 
in veterans with different LBP experiences are associated with potential differences in spinal 
loads (i.e., Aim 2). 
Persistent physical abnormalities (§1.4), which are likely influenced by psychological 
factors, could potentially lead to adaptive changes in lower back MB. For instance, 
asymmetric trunk motion and lumbo-pelvic coordination is evident in individuals with 
unilateral lower limb amputation,53, 54 and we have observed asymmetries in reflexive 
and intrinsic stiffness of their lower back.55 We also have shown a reduction in intrinsic 
stiffness, and an increased latency of reflexive responses of trunk muscles to 
unexpected perturbations, following an acute exposure to an awkward working 
posture.56, 57 Higher activation of trunk muscles in both static and dynamic tasks in 
patients with chronic LBP 58-62 has been suggested as a compensatory response of the 
trunk neuromuscular system to impaired spine stability,63 a response that is associated 
with higher spinal loads.64 Lower back MB directly influence spinal stability, hence, such 
a compensatory response of the trunk neuromuscular system in patients with chronic 
LBP is likely an indication of alterations in lower back MB that might have been occurred 
in the course of transition from acute to chronic LBP. Results of this cross-sectional 
feasibility project (i.e., Aim 1) will equip us with critical preliminary data for future studies 
aimed at investigation of the role of changes in lower back MB in transition from acute 
LBP to chronic disabling LBP. 
In summary and considering the strong evidence in support of a causal relationship 
between spinal loads and LBP, investigation of the role of abnormalities in spinal loads 
in the clinical presentation of LBP (symptom persistence, relapse, or recurrence), is 
clearly critical. As a first step toward addressing such an important research gap, we will 
generate evidence in support of the sensitivity of our methods for capturing potential 
abnormalities in 1) relative contribution of lower back tissues to spinal loads, and 2) the 
resultant spinal loads in veterans with different experiences of non-specific LBP. 
Successful completion of this project will facilitate future longitudinal research to 
determine the role of abnormalities in spinal loads and lower back MB in clinical 
presentation of LBP. Ultimately, the outcomes of such research will support integration 
of measures of lower back mechanics in clinical assessment of veterans with LBP, 
hence will allow identification of veterans at risk for symptom persistence/relapse due to 
abnormal spinal loads. Availability of such a capability in clinic will enable clinicians to 
better match patients with existing physical and psychological treatments or even may 
lead to development of more effective new treatments. The resultant improvement in 
clinical outcome of treatment for non-specific LBP is likely to reduce reliance on opioids 
for management of chronic LBP. 
3.0 
Objectives 
• Relevance to VA Mission, Veterans health and or healthcare issues 
• Describe the study’s purpose, specific aims, or objectives.  
• State the hypotheses to be tested. How will the aims or objectives test the 
hypothesis? 

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Opioids are the most common prescription pain medications among patients with chronic low 
back pain (LBP),11 and more than half of regular opioid users report LBP.12 Not surprisingly, 
there is a strong association between opioid consumption and LBP among veterans.8-10 
According to a recent national survey, more than a third of veterans reported an episode of 
significant LBP in the prior three months.4 At its chronic stage, LBP is among the top ten 
reasons for veterans to receive disability compensation.65 Effective treatment of LBP is hindered 
by an inability to determine the underlying source of pain for most cases (referred as non-
specific LBP). Accordingly, unsatisfactory clinical outcomes for LBP are common for a wide 
range of treatments, with two out of three patients with LBP experiencing symptom persistence 
or relapses. 
Considering the current level of opioid consumption for LBP relief, it is critical to go beyond 
patient’s report of symptoms for the management of non-specific LBP, and to implement 
screening tools that can direct us to potential root causes of LBP. One group of such tools 
relates to measures of forces and deformations in spinal tissues, or the “spinal load”, 
experienced in daily life activities. Extensive evidence relates spinal loads to LBP, yet, 
treatment-induced changes in spinal loads are not monitored in patients with LBP. Spinal loads 
are influenced by physical function and psychological characteristics of patient and can change 
due to treatment-induced alterations in trunk neuro-musculoskeletal behavior and lumbo-pelvic 
coordination. Therefore, it is important to equip researchers and clinicians with the latest 
advanced tools that will enable evaluation of spinal loads, and eventually help better match 
patients with treatments, or even designing more effective interventions that mitigate LBP 
persistence/relapses due to biomechanical factors. 
The specific objective of this study is to generate evidence in support of the feasibility of our 
developed methods for the evaluation of 1) relative contribution of lower back tissues to spinal 
loads, and 2) the resultant spinal loads experienced during daily activities in veterans with 
non-specific LBP. Results of this feasibility study will enable proper design of our future 
projects, wherein we will investigate the role of spinal loads experienced in daily life activities in 
clinical presentation of LBP. We have developed several innovative computational and 
experimental methods for a comprehensive and personalized assessment of spinal loads. 
Specifically, the relative mechanical contribution of active and passive lower back tissues to 
spinal loads is assessed using advanced measures of [bulk] lower back mechanical behavior 
(MB), whereas muscular responses to physical demands of daily activities and the resultant 
spinal loads are evaluated using our finite element model of human spine. We have used the 
methods proposed in this application extensively for evaluation of [bulk] lower back MB and 
spinal loads in asymptomatic individuals. This project will demonstrate the sensitivity of our 
measures for capturing abnormalities in lower back MB and spinal loads in patients with non-
specific LBP by completing the following two aims to achieve our objective [given the feasibility 
nature of this project and lack of adequate power, no specific hypothesis has been provided]:  
Aim-1: Feasibility of distinguishing potential differences in lower back MB between 
veterans with different LBP experiences. We will characterize lower back MB in three 
gender-balanced groups of veterans between 20 and 70 years old. These will include veterans 
with 1) chronic LBP and a Roland-Morris Disability Questionnaire (RMDQ) score of >12 (n=18), 
2) chronic LBP and RMDQ score of ≤12 (n=18), 3) no recent history of LBP and currently 
asymptomatic (n=18), serving as control group). Participants will be recruited from the 
population served by the Lexington, KY, VA Medical Center. We will determine passive stiffness 
of the lower back and its relaxation along with its active intrinsic and reflexive mechanical 
properties, using our sudden perturbation and stress-relaxations tests. Given the reported 
differences in trunk neuromuscular behavior and lumbo-pelvic coordination, we expect to see 
differences in our measures between patient groups targeted for this project. 

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Aim-2: Feasibility of distinguishing potential differences in spinal loads between 
veterans with different LBP experiences. Trunk muscle forces and the resultant spinal loads 
will be determined in the same participant groups when they perform common activities of daily 
living like walking and manual material handling. Considering the causal role of spinal loads, 
and given the persistence of symptom in patients with chronic LBP, along with the high risk of 
LBP recurrence in patients with non-chronic LBP and those with a recent history of LBP, we 
expect differences in spinal loads between patient groups. 
Our long-term goal is to help uncover the potential role of spinal loads in clinical 
presentation of LBP by facilitating the assessment of lower back MB and spinal loads in 
clinics. If such a role is established, our measures can be used to identify veterans at 
risk for [symptom relapse, or transitioning to disabling chronic LBP] due to 
biomechanical factors, and can guide novel, integrated physical and psychological 
treatments aimed at improved lower back mechanics. Ultimately, the resultant 
improvement in clinical outcome of treatment for non-specific LBP is likely to reduce 
reliance on opioid for management of chronic LBP. 
4.0 
Resources and Personnel 
 
• Include where and by whom the research will be conducted.  
• Provide a brief description of each individual’s role in the study.  Be sure 
to indicate who will have access to protected health information and who 
will be involved in recruiting subjects; obtaining informed consent; 
administering survey/interview procedures; and performing data analysis. 
• If applicable provide information on any services that will be performed by 
contractors including what is being contracted out and with whom. 
• If applicable provide information on any Memoranda of Understandings 
(MOUs) or Data Use Agreements (DUAs) that are being entered into 
including with whom and for what reason. 
Data collection and analyses will be conducted in a designated research space in the 
Lexington VA Medical Center on Leestown Road, building 27, room #003E. The current 
research team include Dr. Bazrgari (PI) and Dr. Wolfe (Co-Investigator), Dr. Salt 
(Research Staff), Clare Tyler (Research Staff), Allison King (Research Staff), Evan 
Brown (Research Staff), Amy Pohle (Research Staff), and Vanessa Ramirez, PT 
(Research Staff). Dr. Kryscio (biostatistics) will be included later on for statistical support.  
The study will not involve accessing protected health information of participants. 
Dr. Bazrgari, PI, will have the overall responsibility and will lead all aspects of the project 
including protocol implementation, data collection and analyses, computational 
modeling, results interpretation and dissemination. He will also be responsible for 
recruiting and training of research personnel who will be assisting with subject 
recruitment, data collections and analyses.  
Dr. Wolfe, Co-Investigator, will provide specific contributions in recruitment, consenting 
and medical screening of potential participants to assure their overall eligibility (i.e., 
meeting the primary inclusion/exclusion criteria) for the study. 

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All Research Staff will assist with screening of potential participants, and will also 
contribute to experimental studies. 
Clare Tyler will assist in subject recruitment, consenting, data collection and data 
analyses. 
Dr. Kryscio will oversee our statistical analyses.  
5.0 
Study Procedures 
5.1 Study Design 
• Study Design:Describe experimental design of the study.  Include 
sequential and/or parallel phases of the study, including durations, 
and explain which interventions are standard of care and which 
procedures are being done for research purposes.   
This is a cross-sectional, observational study to investigate differences in 1) active and 
passive aspects of lower back MB and 2) spinal loads experienced during simulated 
daily activities between three veteran groups. Each participants will complete one data 
collection session during which they will complete a number of experiments and surveys.  
 
• Risk vs Benefit: Include a description of how anticipated risk will 
be minimized and include an analysis of risk vs. potential benefit. 
The potential risks of this study will be outlined in the informed consent document, and 
discussed with participants during the screening meeting. While the risk associated with 
the tasks performed during biomechanical assessment is no more than the risk 
experienced during daily life, some participants may experience muscle and/or joint 
soreness associated with the tests that are self-limiting and last a few minutes to a few 
hours. Mild discomfort may also occur during EMG preparation consisting of mild skin 
rubbing (with alcohol), possible shaving (with electric clippers), and the removal of 
adhesive tape holding the electrodes after test completion. The PI have run similar 
experiments with well over 100 healthy participants and 30 patients with LBP without any 
adverse incidents. Also, no injuries have been reported from similar measurements in 
the literature. Participants may feel unpleasant or uncomfortable answering some 
questions on the self-reported questionnaires. We will ensure participants that their 
answers are confidential and also inform them that they may choose not to answer any 
question. 
 
Data security protections: To protect confidentiality, data on paper will be kept in locked 
filing cabinets and will be identifiable only by unique study ID numbers. Identifying 
participant information will be kept separate from other study-related materials. 
Computer files will be kept in password-protected computers with access restricted to 
the members of the study team who will use this information to recruit participants or 
obtain follow-up data. Computer files will also be backed up on a VA designated network 
location as well as on a VA-approved encrypted hard drive which will be used primarily 
for transfer of computer files between PI’s VA and UK labs. No electronic data will 
contain participants’ identifying information. Only study personnel who are approved by 

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Institutional Review Board will have access to the lab wherein all study equipment and 
materials are housed.  
Emotional distress or sadness in completing self-report measures: In the event that 
answering any study questions elicits emotional distress or sadness, study personnel will 
assist participants to access counseling services through their primary care provider. 
Biomechanical assessment: Risks of muscle strain and soreness during our proposed 
experimental tasks is considered low, as the movement associated with these tests is 
self-selected pace. Risks of skin irritation from the EMG electrodes will be minimized by 
asking the subjects if they are aware of any allergies or susceptibility to rashes. 
Research clinicians and biomechanical personnel conducting the tests will monitor 
participants closely and stop the testing procedure if safety is or is potentially 
compromised. Testing will also be terminated by participants or at the participant’s 
request. 
We have implemented all of the proposed biomechanical methods in this application in 
our earlier studies of asymptomatic individuals (see Research Approach). However, the 
proposed sudden perturbation and stress-relaxation tests will be done on patients with 
LBP for the first time in our lab. Similar tests on patients with LBP have been reported in 
the literature,70-72 therefore, we do not expect failure in the conduct of the proposed tests. 
It is of note that our perturbation testing device has several redundant safety measures. 
Participants hold a safety switch, which must be depressed to activate testing 
equipment. Testing is immediately discontinued due to electrical power loss if the 
participant releases the safety switch. Participants will be instructed to release the switch 
and de-activate testing equipment if they experience discomfort during the perturbation. 
The perturbation test has a limit stop switch that cuts all power to the motor if the motor 
rotates more than 60 degrees past its normal range, limiting accidental perturbation to 
approximately 2cm. A manual emergency power switch is located on the front of the 
frame, reachable both by participants and study personnel, with additional power 
switches on the electrical power box and within the computer software that controls the 
motor. Finally during the stress-relaxation test, the participant’s leg will be raised using a 
slow speed (3 deg/second) actuator which can be stopped immediately at subject’s 
request. 
Direct benefits to the subjects are minimal; in particular, there are no immediate health 
benefits of participating in the proposed study. A potential indirect benefit is further the 
understanding of LBP for patient veterans.  
LBP is a significant health problem and is strongly associated with opioid use among 
veterans.3-6 Despite decades of intensive research efforts, LBP persistence, recurrence, 
and transition from the acute to chronic stage is not managed effectively for majority of 
patients.14-17 This clinical challenge arises, in part, because of the inability to determine 
the etiology of symptom (i.e., patients with non-specific LBP). The objective of this 
feasibility project is to verify the sensitivity of our biomechanical outcome measures for 
capturing potential differences in lower back mechanics between veterans with different 
LBP experiences. Successful completion of this project will warrant conduct of larger 
projects (i.e., using merit grant mechanism) to verify the role of lower back 
biomechanical abnormalities in LBP presentation. Given technological advances that 
have made biomechanical assessment more accessible, screening patients with non-
specific LBP for biomechanical abnormalities can help reduce the possibility of symptom 
persistence and relapse due to excessive force and deformation experienced in spinal 
tissues. Improvement in clinical outcomes of treatment for non-specific LBP will diminish 

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reliance on opioids for the symptom management of particularly veterans with chronic 
LBP. 
• Patient Population: Provide description of the study population 
(delineate all categories of subjects – patients, providers, family 
members, employees, etc.). Include anticipated enrollment 
numbers. How many participants.samples per group studies? 
Justify the sample size to obtain power for statistical analysis.  
We will conduct a cross-sectional study involving three groups of research participants 
with and without LBP:  
Group-1: Veterans with chronic, non-specific LBP and a Roland-Morris Disability 
Questionnaire (RMDQ) score of >12 (gender-balanced, n1=18)  
Group-2: Veterans with chronic, non-specific LBP and a RMDQ score of ≤12 (gender-
balanced, n2=18)]  
Group-3: Asymptomatic veterans with no recent history of LBP (gender-balanced, 
n3=18) 
Sample size justification: The purpose of this SPiRE project is to generate the required 
data for effect size calculation of future merit grants. In the absence of preliminary data 
from veterans with LBP, we calculated a sample size using effect sizes estimated from 
our earlier investigations of back-healthy individuals as well as reports of relevant 
measures in the literature. Based on our earlier studies of asymptomatic individuals,56, 57, 
66 a sample size of 10 would have a power of >80% for detection of significant (p = 0.05) 
differences in the proposed measures of lower back MB following acute exposure to 
awkward working posture. Further, using results in the literature,67-69 a sample size (i.e., 
sum of two groups) of 18 was estimated  to detect reported significant effect sizes 
between individuals with and without LBP with 80% power. Therefore, a sample size of 
18 for each group is selected to facilitate sample size calculation and power analyses for 
our future merit grant applications while maximizing our chances of discovering potential 
differences in lower back MB and spinal loads between groups. 
• Vulnerable Populations: As applicable, provide information on 
any added protections for vulnerable populations. 
Not Applicable  
• Data and Specimen Banking: If applicable include information on 
data and specimen banking. 
Not Applicable 
 
5.2 Recruitment Methods 
• State how many subjects will be needed.  
• Describe when, where, how and by whom potential subjects will be 
identified and recruited.  
• Describe materials that will be used to recruit subjects, e.g., 
advertisements.  Include materials as an appendix or separate 
attachment. 

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• Describe any payments to subjects, including the amount, timing (at 
the end of the study or pro-rated for partial study participation), 
method (e.g., cash, check, gift card), and whether subjects will 
experience a delay in receiving the payment.
We will recruit 54 gender-balanced veterans in the following three groups: 1) with 
chronic, non-specific LBP and a Roland-Morris Disability Questionnaire (RMDQ) score of 
>12 (n=18), 2) with chronic, non-specific LBP and a RMDQ score of ≤12 (n=18), 3) 
asymptomatic and no a recent history of non-specific LBP (n=18; serving as control 
group) 
Participants will primarily be recruited from veteran populations receiving treatments at 
the Lexington VA Medical Center in Lexington, KY. This center has two facilities and 
several community-based clinics in the surrounding areas, and serves a population of 
more than 92,000 veterans. Veteran population in our local communities who do not 
receive care at the Lexington VA Medical Center will also be recruited. Dr. Wolfe (Co-I) 
from the Department of Physical Medicine and Rehabilitation, with assistance from 
Vanessa Ramirez (Clinical Research Assistant), will lead our patient recruitment efforts. 
Recruitment will be done between months 6 and 18 of the project period. During this 
period, PI and Co-I will meet providers that see patients with LBP to seek their 
assistance in identification of patients with LBP. This will include, but not limited to, 
primary care physicians, physical therapist, chiropractors, acupuncturists, and etc., to 
inform them about the study and target patient population. These providers will be asked 
to inform their potentially eligible patients about our study and give them our IRB 
approved recruitment flyer. In addition to posting flyers in these clinics, we will have one 
of our research staff to be present in select days to provide more information to the 
interested patients. We will also distribute our study flyers to local institutions that serve 
Veterans. The distribution of study flyers will also include the use of listservs that will be 
sent to Veterans who are studying at the University of Kentucky. 
The recruitment flyer describes the main inclusion/exclusion criteria, contact information 
of the PI, location and duration of experiments and the amount of compensation. 
Participants will be compensated for their time and efforts in participating in the study for a total 
of $40.  
5.3 Informed Consent Procedures 
• Indicate if informed consent will be obtained and/or if you are 
requesting a waiver of informed consent or waiver of 
documentation of informed consent.  If the research involves 
multiple phases, specify for which phases of the research the 
waiver(s) is being requested and/or the informed consent will be 
sought. 
• Describe who will be obtaining informed consent, if applicable, and 
any circumstances that may need to be addressed (e.g. subjects 
with impaired decision making ability and the use of a legally 
authorized representative, etc.) 

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• If applicable, indicate how local site study personnel will be trained 
regarding human subjects protections requirements and how to 
obtain and document informed consent. 
This project requires written documentation of informed consent from all study 
participants. Approval of the informed consent document, the study protocol, and 
recruitment materials will be obtained before data collection begins. During the informed 
consent process, research personnel will explain the handling of data and personal 
health information and guide potential participants through the study consent form. 
Additionally, study staff will explain the study requirements and provide a study flow 
chart and information sheet to the potential participant. This will include an explanation 
of the interview time commitments and biomechanical assessments, potential risks of 
participation, potential benefits of participation, what to do if an adverse event occurs, 
and the option for discontinuation of study participation. Participants will be informed that 
they may choose to stop participating in the study at any stage. Once informed consent 
is administered, both the participant and research personnel will sign and date the 
consent form. A copy of the consent form will be provided to the participant. 
Finally, all study personnel will have up-to-date training in human subject’s protection 
and study procedures. 
5.4 Inclusion/Exclusion Criteria 
• Describe the criteria that determine who will be included in or 
excluded from the study.  
Inclusion/Exclusion Criteria 
 
Group-1 
Group-2 
Group-3 
Current 
condition 
Non-specific LBP 
Non-specific LBP 
Asymptomatic 
LBP Experience 
Chronic* 
Chronic* 
No recent history 
RMDQ score 
>12 
≤12 
N/A 
Pain severity (0-
9) 
≥2 
≥2 
N/A 
Inclusion criteria 
• 
Age between 21 and 70 years old  
• 
Body mass index between 18 and 32 
Exclusion 
criteria 
• 
Any spinal surgery [e.g., spinal fusion surgery] 
• 
Any abnormalities in lower extremity joints due to disease or injury 
that would likely affects lower back mechanics [e.g., lower limb 
amputation or peripheral arterial disease] 
• 
Any safety concern [e.g., pregnancy] 
• 
Any medical condition for which we can’t determine the impact of 
our experimental procedures. [e.g., we don’t know whether our 
measurement instrument will affect pacemakers.] 
• 
Inability to read or verbally comprehend English 
• 
Unwilling or unable to comply with study protocol 
• 
Retention of legal advice or an open / pending legal case related to 

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LBP 
• 
Definition recommended by the NIH task force on research standards for chronic LBP 
will be used: a pain in the lower back on more than half of days over the past 6 
months. 
Eligibility of participants will be determined in a two-step screening procedure involving an initial 
brief screening followed by an on-site screening. The brief screening will be done over phone for 
participants who contact the study personnel via information given in the flyer or it will be done 
in the clinic by the research staff who will be present in clinic for participant recruitment. During 
the brief screening an overview of study objectives and procedures will be provided, and the 
following provisional eligibility criteria will be verified: 
• 
Age between 21 and 70 years 
• 
Body mass index between 18 and 32, calculated using self-report of weight and height 
• 
Current, a recent history, or no recent history of LBP 
• 
Any spinal surgery [e.g., spinal fusion surgery] 
• 
Any abnormalities in lower extremity joints due to disease or injury that would likely 
affects lower back mechanics [e.g., lower limb amputation or peripheral arterial disease] 
• 
Any safety concern [e.g., pregnancy] 
• 
Any medical condition for which we can’t determine the impact of our experimental 
procedures. [e.g., we don’t know whether our measurement instrument will affect 
pacemakers.] 
• 
Inability to read or verbally comprehend English 
• 
Retention of legal advice or an open / pending legal case related to LBP 
Those who are provisionally eligible and still interested will then complete an on-site screening, 
consisting of informed consent process and final eligibility screening. Dr. Wolfe (Co-I) will 
oversee the on-site screening. Dr. Bazrgari (PI) together with Dr. Wolfe (Co-I) will then review 
the results of each screening and decide about the eligibility of the participants. Participants 
deemed eligible will be scheduled for the data collection which can also take place immediately 
after eligibility determination. The study will be conducted in a newly developed lab for studies of 
the human musculoskeletal biomechanics that will be directed by Dr. Bazrgari.  
5.5 Study Evaluations 
• Describe all evaluations to be conducted (including screening; 
tests/questionnaires that will be administered; any procedures that 
subjects will be required to complete) and data collection methods.  
Include materials as an appendix or separate attachment. 
In each data collection session, participants will first be instrumented with sensors to enable 
measurement of kinematics and muscle activity, similar to procedures we used in our earlier 
studies.70-73 Specifically, wireless inertial measurement units (Xsens MTW, Xsens Technologies, 
Enschede, Netherlands)74 will be used to measure rotations of the thorax and pelvis, and 
surface EMG electrodes will be used to measure the activity of erector spinae, rectus 
abdominus, internal and external obliques. Participants will then be asked to stand on a force 
plate and perform a forward bending and backward return test.38, 72, 75 Participants will be 
instructed to bend from an upright standing posture to their maximum comfortable forward 
bending posture and then return to the upright posture at a self-selected pace. Participants will 
then be instructed to perform the following activities of daily life at a self-selected pace: walking 
on level76, 77 surfaces, sit-to-stand and stand-to-sit motions,79 and lowering and lifting a 10 lb 
load to their knee height.80 These activities have been selected because they represent basic 

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Figure 1. Setup for the trunk perturbation 
and stress-relaxation tests. 
Figure 2. Setup for the trunk stress-
relaxation tests. 
but repetitive activities of daily life, and we have successfully used them in our earlier 
investigation of spinal loads among asymptomatic non-veterans, as well as persons with 
unilateral lower limb amputation. Finally, sudden perturbation followed by stress-relaxation tests 
will be conducted as in earlier studies and as explained below. Each of the above tests will take 
less than 5 minutes, and we will provide break periods between each set of tests to minimize 
fatigue and discomfort.  
In preparation for future projects, we will also administer the following questionnaires that are 
relevant to LBP experience during the data collection session: 1) comprehensive health status 
using the PROMIS-29 questionnaire81 ([all participants]), 2) survey of habitual physical activity82 
(all participants), 3) the short version of Copenhagen Psychosocial questionnaire concerning 
work and non-work-related factors83 (all participants), [4) the minimum data set recommended 
by the NIH task force on research standards for chronic LBP (only veterans with LBP)], 5) pain 
intensity using a numerical rating scale84 (only veterans with LBP), 6) LBP-related disability 
using the 24-item Roland Morris Disability Questionnaire85 (only veterans with LBP), 7) the fear-
avoidance beliefs questionnaire86 (only veterans with LBP), pain catastrophizing scale 
questionnaire (only veterans with LBP), and pain self-efficacy questionnaire (only veterans with 
LBP). Total time for the entire data collection session, including the instrumentation time, is 
estimated to be less than 3 hours. 
Characterization of lower back MB: Sudden perturbation and stress-relaxation tests will be used 
to characterize [bulk] active and passive aspects of lower back MB. Sudden perturbation tests 
will be conducted in a displacement-control manner that we have developed, which provides 
separate quantification of both active reflexive and intrinsic stiffness of the lower back.71, 73 Here, 
intrinsic stiffness refers to aspects of lower back MBs that are quantified during the reflex delay 
period (i.e., between perturbation onset and reflexive muscle response), and which incorporate 
both passive and active contributions of lower back tissues. However, the passive contribution 
of tissues to intrinsic stiffness in upright standing posture (i.e., the position used in our 
experimental setting) is minimal;87 therefore, intrinsic 
stiffness primarily reflects the contribution of background 
muscle activities. 
During the sudden perturbation test, participants will 
stand in a metal frame that restrains the pelvis and lower 
limbs [to isolate the lower back response] (Fig. 1). 
Horizontal position perturbations, generated by a 
servomotor (Kollmorgen AKM53K, Radford, VA, USA), 
are transmitted to the trunk (T8) via a rigid harness-rod 
system. A one-minute sequence of anteroposterior trunk 
displacements (± 5 mm) is induced with a pseudo-
random set of delays between each. The driving force 
during the perturbations will be measured using an in-
line load cell (Interface SM2000, Scottsdale, AZ, USA) 
located next to the motor, whereas the resulting kinematics (small displacements with high 
accelerations) will be measured using two laser displacement sensors (Optex FA, Kyoto, 
Japan), with one targeting the back of the harness at the T8 level, and the other targeting the 
load cell.  
The sudden perturbation frame is designed so that trunk 
flexion can be achieved by raising the participant’s 
legs/pelvis using an actuator (Fig. 2); rotation of the lower 
body is about the L5-S1 while the trunk is kept upright. 
Accordingly, the stress-relaxation tests will be conducted 
in the same setup used for the perturbation tests, by 

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Figure 3. FE model of the trunk. Spine geometry and material properties 
(left), and lateral/sagittal views of muscle architecture (right).  
rotating the participant’s legs around his/her lower back using an actuated platform.70, 88 The 
lower extremities and the pelvis of participants will be constrained to the platform and the thorax 
position will be fixed (Fig. 2). Therefore, the amount of lumbar flexion will be the same as the 
amount of platform rotation. During stress-relaxation tests, we will specifically rotate the leg 
platform to the extent that it generates 70% of the lumbar flexion angle that can be achieved 
during a trunk forward bending and backward return activity, as described in §2.6. This posture 
will be maintained for 4 minutes, during which trunk resistance (via load cell) will be measured.  
We have extensively used the methods proposed here in our earlier studies of asymptomatic 
individuals 56, 57, 70, 88 and persons with unilateral lower limb amputation.55 Our sudden 
perturbation and stress-relaxation tests yield excellent within-day (ICC>0.85) and moderate-high 
between-day (ICC=0.5-0.8) reproducibility of measures of lower back MB.66 
Estimation of spinal loads: The 
computational strategy that will 
be used to estimate spinal loads 
is our non-linear finite element 
(FE) model of the spine that, 
accounting for passive 
contribution of lower back 
tissues, can estimate the 
required muscle forces to 
complete a particular task using 
an optimization-based iterative 
procedure.89 This advanced 
kinematics-driven FE model can 
provide a more nuanced 
approach to revealing the 
foundations of spinal loads in 
relation to LBP, and addresses 
several important shortcomings 
of existing models. For instance, geometrical nonlinearities have been included in our model by 
representing the spine as a set of flexible beam elements that mimic intervertebral discs and 
rigid elements that mimic the thorax and lumbar vertebrae (Fig. 3). Material nonlinearities are 
also considered in our model by incorporation  of intervertebral disc stiffness using nonlinear 
axial compression-strain relationships, along with moment-rotation relationships in the 
sagittal/coronal/transverse planes that have been obtained from earlier numerical and 
experimental studies of lumbar spine motion segments.90-92  
Other modeling approaches generally predict trunk muscle forces on the basis of satisfying 
equilibrium at only one spinal level (i.e., often at the L4-L5 or L5-S1),64, 93, 94 and therefore result 
in the prediction of muscle forces that violate equilibrium requirements at other spinal levels.95 In 
our improved model, muscle forces are estimated such that equilibrium requirements are 
satisfied across the entire lumbar spine. Our model also includes a detailed trunk muscle 
architecture (Fig. 3), wherein muscle wrapping around underlying tissues is considered.96 The 
muscle architecture in our computational model includes 56 muscles (Fig. 3); 46 muscles 
connecting the lumbar vertebrae to the pelvis (i.e., local muscles), and 10 muscles connecting 
the thoracic spine/rib cage to the pelvis (i.e., global muscles). To determine the required muscle 
forces for the satisfaction of equilibrium across the entire lumbar spine, segmental kinematics in 
the lumbar region are required. Since only whole-body level kinematics data are available from 
experimental measurements, a heuristic optimization procedure will be used with our model to 
determine a set of segmental kinematics in the lumbar region (i.e., from L1 to L5), such that the 
corresponding set of predicted muscle forces minimize a cost function.97 The cost function that 
will be used for this heuristic optimization procedure will be the sum of squared muscle stress 

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Figure 4. The slope of loading side and 
the moment drop on the relaxation sides 
of curve denote respectively average 
passive stiffness (Kave) and viscoelastic 
relaxation (R). Adopted from ref #66. 
across all 56 lower back muscles. We have recently published a detailed description of this 
procedure in Journal of Biomechanics.97 Predictions of lumbar segmental kinematics from this 
model provide good-excellent agreement with those from image-based measurements.97 The 
associated muscle forces with the optimal local kinematics will then be used to determine spinal 
loads at all lumbar levels. This heuristic optimization procedure was developed in Matlab (The 
MathWorks Inc., Natick, MA, version 7.13), and FE simulations will be conducted in 
Abaqus/CAE (Version 2018, Dassault Systemes Simulia, Providence, RI). 
We have used our FE computational model extensively to study occupational risk factors for 
LBP, including manual material handling,35, 98 trunk motion at different velocities,89 whole body 
vibration,99 impact,100 and sudden loading/unloading.101, 102 The bio-fidelity of our model-based 
predictions of trunk muscle forces and spinal loads has been demonstrated both in static and 
dynamic situations. More specifically, good-to-excellent correlations were found between model 
predictions and measured trunk muscle activity (R>0.7),101 with measured ground reaction 
forces (R>0.8),89 and with measured trunk resistance to sudden loading (R>0.8 unpublished 
data from103). In an ongoing collaboration with Walter-Reed National Military Medical Center, we 
are using our model to estimate spinal loads in service members with and without unilateral 
lower limb amputation while they performed activities similar to those proposed in this project.76-
79 
  
Data analyses- Aim-1: From the perturbation tests, we 
will obtain three outcome measures: reflex latency (t), 
intrinsic stiffness (KIN), and maximum reflexive force 
(FREF). Latency of reflexive responses of trunk muscles 
will be estimated using a system identification approach 
and by relating muscle activity to trunk displacement.71 
Intrinsic stiffness will be estimated using a system 
identification procedure, and by relating trunk kinematics 
with trunk kinetics, respectively, from displacement 
sensors and load cell obtained during the latency 
period.73 To obtain the maximum reflexive force, the 
reflexive responses of lower back will be estimated by 
subtracting the intrinsic response from the measured 
trunk response (i.e., reaction force from load cell) over a 
time window between the end of latency period and 150 
msec post perturbation.57 From the stress-relaxation test, 
we will obtain the average passive stiffness (Kp) and viscoelastic relaxation (R) of lower back 
tissues as shown in Figure 4.70, 88  
Data analyses-Aim-2: Outputs of FE simulations of daily activities will include forces in 56 trunk 
muscles and spinal loads at all lumbar spine levels.98, 99, 102 These outputs will be estimated for 
each instance of each simulated activity described in §2.6. To facilitate quantitative comparison, 
and considering that maximum spinal load at each instant often occurs at the lowermost level of 
the lumbar spine, we will extract the maximum spinal load experienced at the L5-S1 level during 
each activity. The measure of spinal load for each participant will then be calculated as follows 
for statistical analyses: 
 wherein norm denotes the magnitude 
of vector summation and SLactivity denotes the maximum spinal load under each activity. 
 
5.6 Statistical Analysis 

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• What statistical test will be done? 
• Provide sample size determination and analysis (include 
anticipated rate of screen failures, study discontinuations, lost to 
follow-up etc.). 
• Describe how, where and by whom the data will be analyzed. 
For each measure (i.e., reflexive latency, intrinsic stiffness, reflexive force, passive stiffness, 
and stress relaxation from Aim 1, along with the spinal load, SL, from Aim 2), we will run a 
univariate analysis of variance to verify potential differences between study groups (i.e., 
independent factor: participant group with five levels). A significant ANOVA will be followed with 
post-hoc pairwise comparison using Bonferroni’s procedures. Prior to these analyses, 
parametric assumptions will be evaluated. As needed, data transformations will be used, or a 
non-parametric approach will be employed. 
The statistical analyses will be led by the PI will be overseen by Dr. Kryscio 
 
5.7 Withdrawal of Subjects 
• Describe any anticipated circumstances under which subjects will 
be withdrawn from the research without their consent.  
• Describe the consequences of a subject's decision to withdraw from 
the research and the procedures for orderly termination of 
participation by the subject (e.g., the subject contacting the 
investigator for an end-of-study visit). 
Except for the noted exclusion criteria, there is no other anticipated circumstances for 
subject withdrawal.  
Participants will complete a screening session upon completion of the consenting 
procedure and then will participate in one data collection session if determined eligible. 
Since it is most likely that the screening and data collection take place in the same visit, 
there is no specific procedure for withdrawal from the study but to inform the research 
personnel that they are no longer willing to complete the study.  
 
5.8 Expected Results 
• Based on literature and hypothesis, what can be expected? 
• 
Alternative Hypothesis if main hypothesis is not confirmed. 
This is a feasibility project and doesn’t involve a specific hypothesis (per SPiRE mechanism 
guidelines). The followings are, however, our expected findings: Given the reported differences 
in physical performance between individuals with and without LBP, we expect differences in 
spinal loads experienced during daily activity between these groups. Considering the high rate 
of LBP recurrence, we specifically expect those with LBP (or a recent history LBP) to 
experience larger spinal loads. Furthermore, we expect differences in lower back MB between 
veterans with chronic and non-chronic LBP. These differences will support future longitudinal 
research to verify whether they are developed during transition to chronic LBP. Therefore, 

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successful completion of this feasibility project will pave the way for future studies (merit grant 
applications) that will verify the role of abnormalities in lower back MB and spinal loads in the 
clinical presentation of LBP. Such an understanding has the potential to help the affected 
veterans, particularly those with disabling non-specific LBP. 
 
6.0 
Reporting 
• Include procedures for reporting unanticipated problems, serious adverse 
events, and protocol deviations. 
Reporting for this study will include an annual report to the VA IRB, regulatory and sponsoring 
agencies at a minimum, with appropriate updates and reports in the event of unanticipated 
adverse event(s). This project represents no more than minimal risk as they involve activities 
participants do during daily life. Further, we do not anticipate moderate, severe, life-threatening 
or fatal adverse events. The PI is responsible for reporting adverse events to the research team 
and to the IRB. Mild adverse events will be reported within 10 working days of the occurrence; 
moderate, severe, life-threatening or fatal adverse events will be reported within 48 hours of the 
occurrence.  
7.0 
Privacy and Confidentiality 
• Data Collection: List sources/procedures for which data will be collected, 
transmitted, stored, maintained and/or shared. 
• Describe whether the study will use or disclose subjects’ Protected Health 
Information (PHI).  
• Describe the steps that will be taken to secure the data (e.g., training, 
authorization of access, password protection, encryption, physical 
controls, Certificates of Confidentiality, and separation of identifiers and 
data) 
Research material obtained for biomechanical assessment during proposed 
biomechanical tests includes non-invasive measures of muscle activity (EMG), kinetics 
and kinematics. Patient health-related data such as psychological characteristics, pain, 
disability, medication use, and health care utilization will be obtained by in-person 
interviews, self-reporting questionnaires, and/or examinations. All data used for this 
project will be obtained only after receiving written informed consent from the participant. 
We will not collect any PHI 
To protect confidentiality, data on paper will be kept in locked filing cabinets and will be 
identifiable only by unique study ID numbers. Identifying participant information will be 
kept separate from other study-related materials. Computer files will be kept on a 
password-protected computer with access restricted to the members of the study team 
who will use this information to recruit participants or obtain follow-up data. Backups of 
computer files will be saved on a VA-designated network space as well as on a VA-
approved encrypted hard drive. The latter will primarily be used for the transfer of 
computer files between the PI’s lab at VA and University of Kentucky. No electronic data 

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will contain participants’ identifying information. Only study personnel who are approved 
by Institutional Review Board will have access to the lab wherein all study equipment 
and materials are housed. 
8.0 
Communication Plan 
• Include plan for ensuring all required local site approvals are obtained and 
notifying the Director of any facility where the research in being conducted 
but the facility is not engaged. 
• Include plan for keeping all engaged sites informed of changes to the 
protocol, informed consent, and HIPAA authorization 
• Include plan for informing local sites of any Serious Adverse Events, 
Unanticipated Problems, or interim results that may impact conduct of the 
study. 
• Include plan for ensuring the study is conducted according to the IRB-
approved protocol. 
• Include plan for notifying all local facility directors and LSIs when a multi-
site study reaches the point that it no longer requires engagement of the 
local facility (e.g., all subsequent follow-up of subjects will be performed by 
the PI from another facility). 
This project is a single site project wherein a single group of researchers (PI, Co-I, and 
research staff) performs all recruitments, screening, data collection and analysis. Any 
potential changes to the protocol will be discussed during weekly lab meetings. 
Considering the above described reporting, research personnel will be trained to 
recognize, respond to, and record adverse events when they occur or immediately after 
they occur to insure the safety of the human subjects; and to report adverse events to 
the PI in a timely manner to insure compliance with institutional policies on human 
subject protection. Research assistants engaged in data collection will contact the PI as 
soon as an adverse event occurs. 
9.0 
References 
 
Bibliography of cited literature: Citations supporting, hypothesis, data collection and 
analysis. 
1. 
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2018; 391(10137): 2384-8. 
2. 
Hartvigsen J, Hancock MJ, Kongsted A, et al. What low back pain is and why we need to 
pay attention. The Lancet 2018. 
3. 
Maher C, Underwood M, Buchbinder R. Non-specific low back pain. The Lancet 2017; 
389(10070): 736-47. 
4. 
Nahin RLJTJoP. Severe pain in veterans: The effect of age and sex, and comparisons 
with the general population. 2017; 18(3): 247-54. 

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5. 
Vos T, Flaxman AD, Naghavi M, et al. Years lived with disability (YLDs) for 1160 
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Schofield DJ, Shrestha RN, Percival R, Callander EJ, Kelly SJ, Passey ME. Early 
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7. 
Schofield DJ, Shrestha RN, Passey ME, Earnest A, Fletcher SL. Chronic disease and 
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8. 
Dobscha SK, Morasco BJ, Duckart JP, Macey T, Deyo RAJTCjop. Correlates of 
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9. 
Hudson TJ, Painter JT, Martin BC, et al. Pharmacoepidemiologic analyses of opioid use 
among OEF/OIF/OND veterans. 2017; 158(6): 1039. 
10. 
Edlund MJ, Austen MA, Sullivan MD, et al. Patterns of opioid use for chronic noncancer 
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11. 
Shmagel A, Ngo L, Ensrud K, Foley R. Prescription medication use among community-
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12. 
Deyo RA, Von Korff M, Duhrkoop D. Opioids for low back pain. Bmj 2015; 350: g6380. 
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Knecht C, Humphreys BK, Wirth B. An Observational Study on Recurrences of Low 
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Kongsted A, Kent P, Hestbaek L, Vach WJTsj. Patients with low back pain had distinct 
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da Silva T, Mills K, Brown BT, et al. Risk of recurrence of low back pain: a systematic 
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16. 
Stanton TR, Henschke N, Maher CG, Refshauge KM, Latimer J, McAuley JH. After an 
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Van Dieën J, Kuijer P, Burdorf A, Marras W, Adams M. Non-specific low back pain. The 
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18. 
Bakker EW, Verhagen AP, van Trijffel E, Lucas C, Koes BW. Spinal mechanical load as 
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19. 
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Kwon B, Roffey D, Bishop P, Dagenais S, Wai E. Systematic review: occupational 
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Coenen P, Kingma I, Boot CR, Bongers PM, van Dieën JH. Cumulative mechanical low-
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Coenen P, Kingma I, Boot CR, Twisk JW, Bongers PM, van Dieën JH. Cumulative low 
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24. 
Kerr MS, Frank JW, Shannon HS, et al. Biomechanical and psychosocial risk factors for 
low back pain at work. American journal of public health 2001; 91(7): 1069. 

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25. 
Marras WS, Lavender SA, Ferguson SA, Splittstoesser RE, Yang G. Quantitative 
dynamic measures of physical exposure predict low back functional impairment. Spine 2010; 
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Norman R, Wells R, Neumann P, et al. A comparison of peak vs cumulative physical 
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27. 
Griffith LE, Shannon HS, Wells RP, et al. Individual participant data meta-analysis of 
mechanical workplace risk factors and low back pain. American journal of public health 2012; 
102(2): 309-18. 
28. 
da Costa BR, Vieira ER. Risk factors for work‐related musculoskeletal disorders: a 
systematic review of recent longitudinal studies. American journal of industrial medicine 2010; 
53(3): 285-323. 
29. 
Coenen P, Gouttebarge V, van der Burght AS, et al. The effect of lifting during work on 
low back pain: a health impact assessment based on a meta-analysis. Occup Environ Med 
2014; 71(12): 871-7. 
30. 
Brinckmann P, Biggemann M, Hilweg D. Fatigue fracture of human lumbar vertebrae. 
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31. 
Lynn B. . Neurogenic inflammation caused by cutaneous polymodal receptors.  Progress 
in brain research: Elsevier; 1996: 361-8. 
32. 
Solomonow M, Baratta R, Zhou B-H, Burger E, Zieske A, Gedalia A. Muscular 
dysfunction elicited by creep of lumbar viscoelastic tissue. Journal of Electromyography and 
Kinesiology 2003; 13(4): 381-96. 
33. 
Arjmand N, Bazrgari B, Shirazi-Adl A. Modeling and simulation of tissue load in the 
human spine. Routledge Handbook of Biomechanics and Human Movement Science Taylor and 
Francis Ltd, London 2008: 35-49. 
34. 
Arjmand N, Shirazi-Adl A. Model and in vivo studies on human trunk load partitioning 
and stability in isometric forward flexions. J Biomech 2006; 39(3): 510-21. 
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