University of Central Florida University of Central Florida

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Honors Undergraduate Theses UCF Theses and Dissertations

2020

Inter-rater Reliability and Intra-rater Reliability of Synchronous Inter-rater Reliability and Intra-rater Reliability of Synchronous

Ultrasound Imaging and Electromyography Measure of the Ultrasound Imaging and Electromyography Measure of the

Lumbopelvic-hip Muscle Complex Lumbopelvic-hip Muscle Complex

Courtney Caputo University of Central Florida

Part of the Musculoskeletal System Commons

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Recommended Citation Recommended Citation Caputo, Courtney, "Inter-rater Reliability and Intra-rater Reliability of Synchronous Ultrasound Imaging and Electromyography Measure of the Lumbopelvic-hip Muscle Complex" (2020). Honors Undergraduate Theses. 682. https://stars.library.ucf.edu/honorstheses/682

INTER-RATER RELIABILITY AND INTRA-RATER RELIABILITY

OF SYNCHRONOUS ULTRASOUND IMAGING AND

ELECTROMYOGRAPHY OF THE LUMBOPELVIC-HIP MUSCLE COMPLEX

by

COURTNEY CAPUTO

A thesis submitted in partial fulfillment of the requirements

for the Honors in the Major Program in Kinesiology and Physical Therapy

in the College of Health Professions and Sciences

at the University of Central Florida

Orlando, Florida

Spring Term, 2020

Thesis Committee Chair: L. Colby Mangum, Ph.D., LAT, ATC

ii

© 2020 Courtney Caputo

iii

Abstract

Objective: The purpose of this study was to determine inter-rater and intra-rater reliability of

synchronous ultrasound imaging and electromyography measures of lumbopelvic-hip muscle

activity performed by a novice and an experienced investigator in healthy individuals.

Electromyography (EMG) has served as the gold standard for quantification of onset of muscle

activation; however, ultrasound imaging can visualize muscle activity when collected

simultaneously. Methods: A novice and experienced investigator collected a series of 3

ultrasound images at rest and 3 M-mode clips during contraction of each muscle while EMG

electrodes collected muscle activity. Muscles collected included: external oblique, erector spinae,

rectus abdominis, gluteus maximus, and gluteus medius. Participants were asked to return 48-72

hours for a second session. After all muscles were collected, muscle thickness was measured

from the US images and latency based on onset of activity from EMG was processed and

averaged. Results: Moderate inter-rater reliability (ICC2,k=.5-.7) was found for most thickness,

modulated thickness, and latency variables between the experienced and novice raters, however

rectus abdominis had poor reliability compared to the other muscles assessed. Intra-rater

reliability between sessions 1 and 2 for the novice rater revealed moderate reliability (ICC2,k=.5-

.7) in the abdominal muscles (external oblique, erector spinae, contracted rectus abdominis) and

poor reliability in the gluteal muscles. Conclusions: Modulated thickness values had the

strongest reliability for inter- and intra-rater reliability, when thickness measures were divided by

body weight in kilograms before analysis. Subcutaneous tissue, notably abdominal adipose, and

iv

its role on participant positioning should receive added attention during training and instruction

of novice investigators during M-mode acquisition and timing of contraction with EMG

synchronization.

v

Acknowledgements

I would like to express my deepest gratitude towards Dr. L. Colby Mangum for her

unconditional support and encouragement. I am forever grateful for everything she has helped

me accomplish. I would like to recognize and show my appreciation for my committee members

Dr. Hill and Dr. Schellhase. As well as thank them for their amazing advice. I would like to

recognize the invaluable assistance Sara Akbarpour provided throughout my study. Finally, I

wish to thank my friends and family who have been by my side throughout this entire journey

and continuously love and support my dreams.

vi

TABLE OF CONTENTS

INTRODUCTION 1

METHODS 3

RESULTS 7

DISCUSSION 7

CONCLUSION 12

TABLES AND FIGURES 13

APPENDIX A: REVIEW OF LITERATURE 18

LUMBOPELVIC-HIP COMPLEX 19

CORE STABILITY 19

SPINAL STABILIZATION 20

RANGE OF MOTION 20

MEASUREMENT OF MUSCLE ACTIVITY 22

ULTRASOUND IMAGING 22

USI TRAINING 23

ELECTROMYOGRAPHY 24

EMG AND ITS CONNECTION TO USI 24

THICKNESS AND ACTIVATION 25

EMG AND USI SYNCHRONIZATION 26

RELIABILITY OF ULTRASOUND 26

INTER-RATER RELIABILITY 26

INTRA-RATER RELIABILITY 27

SIGNIFICANCE OF STUDY 29

APPENDIX B: ADDITIONAL METHODS 30

BIBLIOGRAPHY 45

1

Introduction

The lumbopelvic-hip complex is comprised of muscles that act as global movers and local

stabilizers, which are all important for individuals to maintain control of core movement during

physical activity. Although superficial, the external oblique (EO) muscle provides rotational

support to the lateral abdominal wall. The rectus abdominus (RA) can be activated when

performing an abdominal crunch1 due to its function in trunk flexion and is equally as important

as the erector spinae (ES). The ES extends vertically along the vertebral column to maintain

posture and aids in trunk extension.2 These muscles within the lumbopelvic-hip complex play a

vital role in the support and stabilization of the spine. Other muscles like

the gluteus maximus (GMAX) and gluteus medius (GMED) are important

in hip rotation, extension, and pelvic stability. Primary and secondary injuries frequently

attributed to strains of these muscles can be debilitating in populations, such as non-specific low

back pain and patellofemoral pain.3 However, use of technology to analyze and monitor these

muscles can be beneficial and improve the interventions used for injured patients.

Ultrasound imaging is a non-invasive method to measure muscle size, shape, and thickness that

can be used to identify short-term or long-term changes in the muscles of the lumbopelvic-hip

complex. Musculoskeletal ultrasound imaging is currently used by a variety of health care

professionals, including radiologists, physicians of multiple specialties, sonographers, athletic

trainers, physical therapists, and occupational therapists. Ultrasound imaging can be used to

visualize muscle activity4 and has shown acceptable to excellent reliability in core muscle

thickness and activity in various positions.3,5

2

Electromyography (EMG) measures muscle response or electrical activity when a muscle is

being stimulated or voluntarily contracted to capture motor unit action potentials. Surface EMG

has been used as a gold standard to quantify the extent of and timing of muscle activation,

however, it can be difficult to use effectively with deeper muscle tissue or with muscles that

overlap one another due to cross-talk of the EMG electrical signal.6 Collecting muscle activity

using both ultrasound imaging and EMG allows researchers and clinicians to visualize and

quantify muscle changes in spatial and electrical manners. This is useful in assessment of a

variety of musculoskeletal injuries and chronic conditions. Ultrasound imaging and EMG have

been used for biofeedback in rehabilitation settings to show the patient how to improve their

muscle activity by visualizing their own muscle activity either on the ultrasound screen or on the

EMG output device.7,8

Clinicians commonly use ultrasound imaging and EMG to effectively assess and monitor muscle

activity. Using musculoskeletal anatomy knowledge and defined landmarks from ultrasound

imaging and EMG literature, the probe and electrodes can be positioned appropriately, and

monitoring can take place. With these aforementioned skills and training, a novice may be

able to acquire these same data from patients and research participants. Reliability as well as the

comparison of a novice and experienced rater should be established prior to moving forward with

a synchronized ultrasound imaging and EMG technique. An assistant or aid who can do such

actions with fundamental training can allow for clinicians and researchers using this

technique to integrate those individuals into their practice and research studies seamlessly.

3

The purpose of this study was to determine inter-rater and intra-rater reliability of synchronous

ultrasound imaging and EMG of lumbopelvic-hip muscle activity performed by a novice and an

experienced investigator in healthy individuals. Our study aimed to show that even a novice with

a short amount of quality training can utilize this tool in a useful manner, specifically for

musculoskeletal ultrasound imaging. To our knowledge, prior research has not established

reliability in the lumbopelvic-hip muscles using this methodology.

Methods

Study Design

A descriptive laboratory study was used to assess inter-rater and intra-rater reliability in muscle

thickness at rest, during contraction, modulated rested and contracted thickness measures, and

latency values using synchronous ultrasound and EMG of the EO, RA, ES, GMAX, and GMED

of the lumbopelvic-hip complex. All measures were collected by two investigators, one novice

and one experienced, during two different sessions 48-72 hours apart.

Participants

Sixteen healthy participants without a history of low back, core, or hip injury participated in this

study. Individuals who reported any previous injuries or surgeries to the lumbopelvic-hip region

or lower extremities were excluded from this study. Participants’ ages ranged between 18-

45 years. Once in the lab, participants were given several questionnaires to evaluate their

physical fitness and activity level as well as to ensure no previous lower back or extremity pain

4

or injuries. Written informed consent was obtained from all participants and the study protocol

was approved by the University’s Institutional Review Board.

Instruments

In addition to questionnaires on health history and physical activity, a SPI-Tronic Pro 360 digital

inclinometer was used to measure and document range of motion for each participant. A hand-

held dynamometer (microFET®2, Hoggan Scientific, LLC., Salt Lake City, Utah) was used to

measure and record maximum volitional isometric contraction (MVIC) force output in N/kg

of all muscles. A portable GE NextGen LOGIQ e (GE Healthcare, Waukesha, WI) ultrasound

unit with a linear transducer was used to visualize brightness mode (B-mode) and motion mode

(M-mode) ultrasound output. To measure onset of electrical muscle activity, a Delsys

Trigno wireless system (Delsys, Inc., Boston, MA) with Trigno Avanti sensors captured surface

EMG data and EMGworks® 4.54 (Delsys, Inc., Boston, MA) was utilized for EMG acquisition.

A standard Dell (Dell, Inc., Round Rock, TX) Latitude 7490 running Windows 10 collected,

stored and analyzed data throughout the study.

Data Collection

All participants completed questionnaires and surveys about their musculoskeletal injury

history, and physical activity level. Following the collection of these questionnaires, height,

weight, and trunk range of motion (trunk flexion, trunk extension, hip abduction, hip

extension) were collected using the inclinometer. Participants had surface EMG electrodes

placed in the areas on the muscles of interest for this study, the EO, RA, ES, GMAX,

5

and GMED on the participant’s dominant side.9 Dominant side was self-reported on the

questionnaires. Once the adhesive electrodes were placed, the ultrasound gel was applied in each

area corresponding to the muscle of interest in the order listed above. The novice and

experienced rater collected a series of 3 ultrasound images at rest and during contraction using

B-mode. The other rater was not present in the room or able to view the screen when they were

not actively collecting. A random number generator was used to determine the order of rater for

each session and allocation was concealed until the start of each session. Following B-mode

imaging, 3 image clips during contraction while the EMG electrodes were collecting muscle

activity, were recorded.10 M-mode or motion mode was used on the ultrasound unit for this series

of contractions for each muscle.11 During M-mode collection, there was an EMG sensor attached

to the USI cart handle with non-adherent tape, to note when the activation of the contraction of

each participant was initiated (when the rater cued the participant to contract). After the rater

began the EMG recording, they initiated the M-mode recording, then immediately the EMG

sensor was tapped causing a spike in electrical activity on the system at the time that the rater

cued the participant to perform the contraction. The participant was then told to relax after

contraction, completing the 5-second interval of M-mode recording. All participants were asked

to return 48-72 hours later to repeat the same collection to determine intra-rater between session

reliability.12,13 After all muscles were collected, the muscle thickness was measured from the

ultrasound images and the delay, or latency, from cueing the participant and tapping the EMG

electrode, to the onset of electrical activity was measured using ImageJ (National Institutes of

Health, Bethesda, MD) and EMGworks (Delsys, Inc., Natick, MA), respectively.14 This data was

averaged from the 3 trials collected from each muscle.15 For EMG collection, a sampling rate of

6

2000Hz was used. A band pass filter of 10-500Hz and a root mean square signal. The signal was

smoothed using a 50ms moving window for the 5-second contraction acquisition. Onset of

activation for the latency variable was defined as the amplitude exceeding 3 standard

deviations16, for greater than 0.25ms, above the baseline (quiet baseline) prior to the

synchronization tapping of the sensor on the USI cart. The novice and experienced investigator

data were compared to determine inter-rater reliability and between session reliability was

compared for intra-rater reliability for the novice.5,13

Statistical Analysis

Intraclass correlation coefficients (ICC2,k) were calculated with a two-way mixed model and 95%

confidence intervals to determine reliability of thickness measures, latency of contraction, and

the activity for both inter-rater and intra-rater. Excellent reliability was interpreted as values

above 0.9, good reliability was known as 0.75-0.9, moderate was noted as 0.5-0.75, poor was

shown to be less than 0.5.17 Paired t-tests were used to assess differences between sessions for

MVIC data from sessions 1 and 2. All reliability and paired t-tests statistical analyses were

conducted using SPSS version 25.0 (IBM Corp, Armonk, NY). Standard error of measurement

(SEM) and minimal detectable change (MDC) were calculated for all variables using Microsoft

Excel (Microsoft Office 365, Microsoft Corp., Redmond, WA). Alpha was set a-prior at ≤ 0.05.

Results

Participant characteristics are depicted in Table 1, including range of motion from session 1 and

strength data collected from both sessions. There were no differences between sessions in any

7

muscle in hand-held dynamometry MVIC measures (N/kg). Muscle thickness at rest (cm), during

contraction (cm), muscle thickness modulated to body weight (cm/kg), activity ratios, and

latency in seconds are summarized for the novice and experienced raters from session 1 in Table

2. Inter-rater reliability between the novice and experienced raters was moderate for most

variables and is presented with SEM and MDC for each variable in Table 3. Outcomes of session

1 and 2 for the novice rater are provided in Table 4, followed by intra-rater reliability in Table 5.

GMED rested thickness revealed the highest inter-rater reliability (ICC2,k=.74), and GMAX had

the highest contracted thickness inter-rater reliability (ICC2,k=.63). Both GMAX and GMED had

consistently the highest inter-rater reliability for latency in timing of contraction delay with EMG

synchronization (ICC2,k=.51). The abdominal muscles had greater reliability for novice intra-

rater reliability compared to the gluteal muscles, as GMAX and GMED had poor reliability

(ICC2,k<0.2) or the average covariance of the variable was negative and the reliability model

assumptions were violated, resulting in a negative ICC value. Those variables are noted with a (-

-) in the ICC column (Tables 3 and 5).

Discussion

Reliability between a novice and experienced investigator, in addition to between session

reliability of a novice investigator were assessed in this study for M-mode ultrasound time-

synchronized with EMG of five different muscles in the lumbopelvic-hip complex. GMED had

the highest reliability for inter-rater reliability across all variables (Table 3) and EO was

consistently the most reliable muscle assessed for intra-rater reliability by the novice rater (Table

5). Inter-rater reliability produced acceptable, moderate results for most M-mode USI measures,

8

which were time-synchronized with EMG onset of activation. The most reliable inter-rater

results were observed when thickness measures were modulated or normalized to body weight in

kilograms. The location of the muscles assessed in this study played a large role in the

contractions performed by the participants and therefore, the measurements acquired by the

raters. Each contraction was performed in order to show that specific muscle being activated. As

body size affected these measures directly, once body weight was adjusted for, most ICC values

improved, some dramatically. The modulated values gave a better representation of that

individual. This was a significant unexpected finding that should be considered when utilizing

this technique of synchronous USI and EMG.

Regarding ES it is important to note that the contour of all of the tissue presented a unique task

when placing the transducer and visualizing facial borders in all participants when using USI.3

The amount of posterior lumbar musculature in each of the healthy, active participants in the

current study added to the extra attention that had to be paid to placement of the ultrasound

transducer during ES image capture, especially during movement. Increased muscle tissue and/or

adipose tissue can make it challenging for even an experienced investigator to obtain an image of

the same quality. Lumbar multifidus has had poor reliability in any position beyond tabletop,

static positions in past studies.3 Inter-rater reliability of the novice and experienced investigators

showed ES measurement with consistent moderate reliability (ICC2.k=.56-.66). The added

attention paid to the placement of the transducer and visualization of the fascial borders by both

investigators may have led to this moderate level of reliability. Additional training and practice

9

in this area was a focus for the novice due to its potential for increased change in muscle tissue

from rest to contraction.

RA had a larger discrepancy between raters compared to other muscles and positioning. RA also

had improved intra-reliability results with the novice investigator when contracted versus when

rested. This could be due to the fact that the facial borders were well defined once the participant

contracted and were unable to be detected amongst the tissue at rest. Measurements with

presence of abdominal fat may have been contributing factors to this inconsistency as well.

Although all participants met American College of Sports Medicine guidelines of a healthy

participant, this study did not incorporate a specific cut off for participants’ body mass index

(BMI). Considering BMI was not a limiting factor, some subjects did have a higher amount of

adipose and abdominal tissue than others as evidenced in the superficial regions of their RA

ultrasound images. This increased amount of tissue can play a major role in the ability to find

and visualize anterolateral muscles on the US. Individuals with increased subcutaneous tissue

necessitated the rater to increase the depth of the USI on-screen in order to get an accurate and

measurable image. To analyze the superior and inferior borders, the depth must be adjusted on

the USI unit and the appropriate depth must be selected before image capture and is up to the

individual rater’s discretion.

Females tend to have a higher percentage of body fat than males.18,19 It has been documented that

females are more effective at storing fat when compared to males.19 Females who have

additional adipose tissue around the lumbopelvic-hip area compared to their male counterparts

10

need to be taken into consideration, when imaging the abdominal region. Although in our study

the proportion of females-to-males was fairly even (females=57%) in the sample, this should be

noted when looking at the reliability of the RA. Imaging a lean individual presented an easier

process of identifying facial borders, particularly for the novice rater. With larger individuals it is

harder to not only identify these borders amongst the tissue, but to also reproduce those images

consistently over time. EO exhibiting a higher intra-rater ICC2,k of 0.63 and 0.66 for rested and

contracted values, respectively supports this notion that there was an ease with visualization of

those facial borders with less subcutaneous tissue in the same view as the muscle of interest for

the novice rater.

Critical aspects that should also be reflected from the intra-rater reliability results include the

trend in reduction of variance from session 1 to session 2 seen in Table 4. Although, all the same

actions were taken in both instances the novice was able to have a better understanding when

locating and visualizing musculature and facial borders, the second time. This could be reflected

in the shift in most rested and contracted thickness measures for the novice rater. The novice

rater’s reliability was moderate and consistent for most of the abdominal muscle variables,

although subtle improvement over time was shown as the standard deviation for group means

decreased based on both the rested and contracted thickness. This could be a resultant learning

effect from the short time period between sessions of only 48-72 hours. The participant may have

had a much better understanding of the instructions given after hearing them several times.

It is also important to understand each subject was given the same instructions while the other

11

rater was not in the room. Each follow-up session with participants was scheduled at a similar

time as their initial session, to avoid interference from changing of mealtimes or attending the

gym, which may have affected some of the abdominal images. Participants were scheduled to

meet 48-72 hours apart at the fixed time as their original session. Even though participants were

in a comfortable environment and given easy to follow directions they may have felt nervous

during the first session and did not give full effort during M-mode capture and contractions,

whereas in the second session they may felt increased confidence and put in added effort leading

to a disparity in thickness and latency. The opposite may have been true for some participants

where they put forth full effort to be impressive in session 1 and lessened their effort during the

second meeting thus altering reproducibility, which may have been especially true with RA. The

abdominal crunch required for the contraction for RA anecdotally was not the most favored

position of the participants throughout data collection and that may have affected overall effort

throughout the sessions and between investigators. Although there were no significant

differences between (p>.05) any of the MVIC strength assessments from session 1 to session 2,

the contractions performed during the M-mode and EMG collection were sub-maximal and may

not have elicited enough of a contraction to produce reliable results consistently.

Conclusion

Moderate, acceptable inter-rater reliability between a novice and experienced rater was found

amongst EO, ES, GMAX, and GMED thickness and modulated thickness, at rest and during

contraction. Intra-rater reliability of a novice between sessions revealed moderate reliability of

EO, ES, and contracted RA measures. Nearly all reliability improved for thickness measures

12

when divided by body weight in kilograms and this adjustment is important for assessment in the

abdominal and hip areas. Visualization of the lumbopelvic-hip complex is multi-faceted and the

location of measurement, and nature of contraction should be considered when training a novice

rater for USI and EMG synchronous collection.

13

Tables and Figures Table 1. Participant Characteristics

Characteristic

Age (years) 21.63±2.36

Height (cm) 169.08±7.44

Weight (kg) 66.86±12.72

Sex 9 female, 7 male

Dominant lower limb

(side of collection)

14 right, 2 left

Tegner Activity Scale 5.94±0.99

PROMIS Global Health 37.5±4.24

PROMIS Physical

Function

99.13±1.15

Range of Motion (°)

Trunk Flexion 35.98±11.18

Trunk Extension 28.59±7.03

Right Hip Extension 23.44±6.44

Left Hip Extension 25.28±7.87

Right Hip Abduction 33.64±9.75

Left Hip Abduction 29.35±10.57

MVIC Force Output

(N/kg)

Session 1 Session 2

External Oblique 0.30±0.06 0.33±0.08

Erector Spinae 0.29±0.08 0.30±0.07

Rectus Abdominis 0.31±0.07 0.31±0.05

Gluteus Maximus 0.51±0.12 0.51±0.09

Gluteus Medius 0.61±0.17 0.57±0.13

14

Table 2. Session 1 Results Summary

Group Means

(Standard Deviation)

Rested

thickness

(cm)

Modulated

rested thickness

(cm/kg)

Contracted

thickness

(cm)

Modulated

contracted

thickness

(cm/kg)

Activity ratio

(contracted/rested

thickness) Latency (s)

N E N E N E N E N E N E

External

Oblique

0.52

(0.17)

0.47

(0.17)

0.008

(0.003)

0.007

(0.003)

0.91

(0.29)

0.85

(0.24)

0.014

(0.006)

0.013

(0.004)

1.94

(0.77)

1.88

(0.44)

1.10

(0.42)

1.20

(0.36)

Erector

Spinae

1.39

(0.62)

1.87

(0.68)

0.022

(0.011)

0.029

(0.013)

2.03

(0.72)

2.51

(0.99)

0.032

(0.012)

0.039

(0.018)

1.56

(0.42)

1.41

(0.58)

1.44

(0.31)

1.31

(0.28)

Rectus

Abdominis

0.88

(0.33)

0.95

(0.37)

0.013

(0.004)

0.144

(0.006)

1.28

(0.46)

1.44

(0.42)

0.019

(0.005)

0.022

(0.008)

1.49

(0.33)

1.67

(0.67)

1.09

(0.54)

1.29

(0.40)

Gluteus

Maximus

0.61

(0.22)

0.79

(0.31)

0.009

(0.004)

0.013

(0.006)

0.82

(0.43)

1.27

(0.66)

0.012

(0.006)

0.019

(0.010)

1.35

(0.47)

1.67

(0.76)

1.30

(0.36)

1.36

(0.67)

Gluteus

Medius

1.06

(0.54)

1.26

(0.67)

0.016

(0.006)

0.019

(0.009)

1.36

(0.55)

1.65

(0.81)

0.021

(0.010)

0.025

(0.013)

1.41

(0.57)

1.35

(0.41)

1.02

(0.34)

1.25

(0.46)

Abbreviations: N, novice rater; E, experienced rater.

15

Table 3. Inter-rater Reliability Summary of Results

Standard Error of

Measurement

Minimal

Detectable Change ICC2.k 95% Confidence Interval

External Oblique Lower Bound Upper Bound

Rested thickness (cm) .10 .28 .63 -.07 .87

Modulated rested

thickness (cm/kg) 0.0070 0.0094 .68 .09 .89

Contracted thickness

(cm) .19 .53 .45 -.58 .81

Modulated contracted

thickness (cm/kg) 0.0014 0.0040 .66 .04 .88

Latency (s) .36 1.00 .14 .01 .67

Erector Spinae

Rested thickness (cm) .37 1.03 .66 .01 .88

Modulated rested

thickness (cm/kg) 0.0027 0.0075 .71 .18 .90

Contracted thickness

(cm) .53 1.47 .56 -.26 .85

Modulated contracted

thickness (cm/kg) 0.0030 0.0084 .62 -.10 .87

Latency (s) .20 .56 .55 .09 .82

Rectus Abdominis

Rested thickness (cm) .32 .89 .15 .53 .60

Modulated rested

thickness (cm/kg) --

Contracted thickness

(cm) .27 .76 .61 -.13 .86

Modulated contracted

thickness (cm/kg) 0.0013 0.0036 .47 -.53 .81

Latency (s) .40 1.12 .20 -1.0 .72

Gluteus Maximus

Rested thickness (cm) .19 .52 .44 -.60 .81

Modulated rested

thickness (cm/kg) 0.00089 0.0025 .55 -.29 .84

Contracted thickness

(cm) .30 .84 .63 -.05 .87

Modulated contracted

thickness (cm/kg) 0.0016 0.0043 .55 -.29 .84

Latency (s) .34 .93 .51 .40 .83

Gluteus Medius

Rested thickness (cm) .31 .85 .74 .26 .91

Modulated rested

thickness (cm/kg) 0.0015 0.0042 .68 .08 .89

Contracted thickness

(cm) .49 1.34 .52 -.37 .83

Modulated contracted

thickness (cm/kg) 0.0025 0.0070 .74 .26 .91

Latency (s) .28 .78 .51 -.39 .83

Abbreviations: cm, centimeter; kg, kilogram; s, seconds.

16

Table 4. Session 1 and 2 Results Summary for Novice Investigator

Group Means

(Standard Deviation)

Rested

thickness

(cm)

Modulated

rested thickness

(cm/kg)

Contracted

thickness

(cm)

Modulated

contracted

thickness

(cm/kg)

Activity ratio

(contracted/rested

thickness) Latency (s)

1 2 1 2 1 2 1 2 1 2 1 2

External

Oblique 0.52

(0.17)

0.50

(0.12)

0.008

(0.003)

0.008

(0.002)

0.91

(0.29)

0.76

(0.29)

0.014

(0.006)

0.012

(0.004)

1.94

(0.77)

1.51

(0.38)

1.10

(0.42)

0.91

(0.24)

Erector

Spinae 1.39

(0.62)

1.45

(0.31)

0.022

(0.011)

0.022

(0.006)

2.03

(0.72)

1.86

(0.30)

0.032

(0.012)

0.029

(0.007)

1.56

(0.42)

1.56

(0.35)

1.44

(0.31)

1.08

(0.37)

Rectus

Abdominis 0.88

(0.33)

0.86

(0.23)

0.013

(0.004)

0.013

(0.003)

1.28

(0.46)

1.31

(0.36)

0.019

(0.005)

0.20

(0.005)

1.49

(0.33)

1.33

(0.30)

1.09

(0.54)

1.00

(0.31)

Gluteus

Maximus 0.61

(0.22)

0.76

(0.14)

0.009

(0.004)

0.012

(0.003)

0.82

(0.43)

1.05

(0.24)

0.012

(0.006)

0.016

(0.005)

1.35

(0.47)

1.38

(0.25)

1.30

(0.36)

1.45

(0.48)

Gluteus

Medius 1.06

(0.54)

0.86

(0.31)

0.016

(0.006)

0.013

(0.005)

1.36

(0.55)

1.10

(0.33)

0.021

(0.010)

0.017

(0.005)

1.41

(0.57)

1.41

(0.39)

1.02

(0.34)

1.07

(0.45)

Abbreviations: cm, centimeter; kg, kilogram; s, seconds.

17

Table 5. Novice Intra-rater Reliability Summary of Results

Standard Error

of Measurement

Minimal Detectable

Change ICC2.k 95% Confidence Interval

External Oblique

Lower

Bound Upper Bound

Rested thickness (cm) .08 .21 .57 -.24 .85

Modulated rested

thickness (cm/kg) .001 .003 .63 -.06 .87

Contracted thickness

(cm) .20 .55 .55 -.28 .84

Modulated contracted

thickness (cm/kg) .002 .006 .66 .03 .88

Latency (s) .15 .41 .64 -.04 .87

Erector Spinae

Rested thickness (cm) .22 .87 .49 -.48 .82

Modulated rested

thickness (cm/kg) .004 .017 .60 -.14 .86

Contracted thickness

(cm) .29 .84 .1 -1 .69

Modulated contracted

thickness (cm/kg) .005 .02 .61 -.12 .86

Latency (s) .25 .70 .53 -.35 .84

Rectus Abdominis

Rested thickness (cm) .21 .59 .12 -1 .69

Modulated rested

thickness (cm/kg) --

Contracted thickness

(cm) .19 .003 .73 .23 .91

Modulated contracted

thickness (cm/kg) 1.01 .01 .54 -.32 .84

Latency (s) .30 .83 .08 -1 .68

Gluteus Maximus

Rested thickness (cm) --

Modulated rested

thickness (cm/kg) .003 .009 .03 -1 .66

Contracted thickness

(cm) --

Modulated contracted

thickness (cm/kg) --

Latency (s) .34 .96 .49 -.45 .82

Gluteus Medius

Rested thickness (cm) --

Modulated rested

thickness (cm/kg) .005 .015 .01 -1 .66

Contracted thickness

(cm) .31 .91 .09 -1 .68

Modulated contracted

thickness (cm/kg) .004 .015 .42 -.65 .80

Latency (s) .39 1.09 .22 -1 .73

Abbreviations: cm, centimeter; kg, kilogram; s, seconds.

18

Appendix A: Review of Literature

19

Lumbopelvic Hip Complex

The lumbopelvic hip complex is known as the area that transitions from your lower to upper

body. Some of the major components of this complex are the rectus abdominus (RA), external

oblique (EO), erector spinae (ES), gluteus maximus (GMAX), and gluteus medius (GMED). The

role of these muscles including how they coordinate with one another for optimal function has

been extensively studied. These muscles as a whole work to be local stabilizers as well as global

movers.20,21 A global mover is known to move the load, while local stabilizers maintain

steadiness throughout the body during such movements. It is critical for our understanding to be

able to correctly visualize and examine this region in healthy individuals in order to aid and

assess the injured population such as those who suffer from low-back pain.22 Studies suggest

that the lumbopelvic hip complex not only plays a major role in the lower extremity movement

during daily tasks and our ability to do daily functions like use the stairs or squat, but it is just as

is important in functions in our upper body for activities like throwing.23

Core Stability

The core is comprised of the RA, transverse abdominus (TrA), EO, internal oblique (IO), ES as

well as piriformis, GMAX, gluteus minimus and GMED muscles.24 These muscles play a major

role in the function, stability and mobility of the core. Core stability is described as one’s ability

to provide strength and control the position and movement of their core complex. A person

having a stable core is said to have better balance and stability in everyday activities whether it

be moving or playing field hockey. Many studies focus on the importance of a stable

core.20,25,26,27,28,29,30 Research has shown that a less stable lumbopelvic hip complex and/or core

20

will cause the body to place more pressure and strain on the specific area instead of using these

particular muscles.23 The ability to recognize, understand, and train your core for stability is so

significant and allows clinicians to prevent injuries and build endurance in athletes.26

Table 1.0 Global Muscles

Stabilizers Mobilizers

TrA RA

GMAX EO

GMED ES

IO

Spinal Stabilization

The primary goal of the spine is to provide strength and spinal stability in order to prevent and

treat the possibility of lumbar damage. The dynamics that affect lumbar stabilization have shown

to be important not only for patients, but for clinicians as well. Exercises that play a role in

enhancing the stabilization of the spine have been shown to have a positive impact on prevention

of injuries and treatments with low back pain when used in clinical settings.31,32 In addition,

patients who report low back pain are able to retrain their muscles and increase spinal stability

while decreasing symptoms of lower back pain by repeatedly doing lumbar stabilization

exercises.33

Range of Motion

Range of motion (ROM) can be determined using different tools and techniques. Goniometers

are a well-known tool for their reliability to measure ROM of joints. They consist of two arms

that can pulled apart or brought closer depending on the extent the patient is able to move. These

21

two arms then determine the degree of the angle at which the patient can bend that joint (as

shown in the image depicted in figure 1.0). Another common way to measure ROM is through

the use of a digital inclinometer. By simply zeroing out the device the tool can then be placed on

the patient and as they abduction/adduct the degree of inclination will be inputted. These devices

are a representation of the motions the joint can move when propelled by muscles meaning from

full flexion to the full extension. ROM is deeply connected and related to many aspects involving

our ability to function on a daily basis. Evidence shows improvement of ROM helps prevent

injuries and further suggests an improvement in trunk muscle strength tests.26 ROM is a

fundamental element in monitoring progress as well as pit falls in patient care plans in clinical

practice.34

Figure 1.0 Goniometer in Use

Measurement of Muscle Activity

22

Ultrasound Imaging

Ultrasound imaging (USI) is a non-invasive technique that uses high-frequency sound waves to

produce images of structures within the body and can aid clinicians in the diagnosis and

treatment of medical conditions and other injuries. The use of USI is increasing amongst

healthcare providers.35 Recent studies have proven USI to be a reliable tool.36,37,38,39 USI are

reliable ways to measure the thickness of muscles by placing the transducer over the specified

muscle region and examining the diameter of the cross-sectional area of said muscle. Thickness

is determined by the distance between the inner edge of each fascicle border.40 USI yield

consistent results in a timely manner.41,42,43 The use of bed side ultrasound imaging can speed up

the process of decision making amongst clinicians and have a beneficial impact on patients when

an early diagnosis is critical.44,45,46,47 B-mode which stands for brightness mode is the most

commonly used method of USI. It is named brightness mode because it depicts 2D images by

transmitting sounds waves which are then either absorbed or reflected based on the water

content, the tissues of the muscles, the US gel, and other make ups in the surrounding area. Once

these sound waves have hit a boundary they are then reflected and recognized by the transducer

which in turn relay the image to the machine. USI works because they use echoes that can

transmit and depict an image during one instant compared to radiation which is a much more

complicated process. In contrast, M-mode stands for motion mode which illustrates time motion

display. The movement being seen on the screen allows for the tracking of facial borders to take

place from their position at rest through the muscle contraction and back to relaxation. Both B

and M-mode can be used to measure muscle thickness.48 However, M-mode plays a critical role

in collecting the duration of contractions in muscles since it is able to record the entire motion of

23

the muscle. When combining the use of M-mode and EMG clinicians can evaluate the two time

domains that take place simultaneously and evaluate the excitation compared to the diameter of

muscle thickness.11

USI Training

A recent survey revealed the lack of musculoskeletal USI training among residents.35

Researchers note the importance and high demand of implementing simple training sessions that

can be from web modules or even peer taught.35 Other studies prove that we can successfully

teach novice students who plan to later become physicians the basics of interventional USI.49 Not

only is USI training achievable it is both valuable and economically favored for clinicians.49

Even emergency medicine residents have been able to confirm having only a short training

course and given basic knowledge of USI devices they can intubate patients.49,50 It has been

shown that implementation of simulator training can advance USI performance on radiology

residents compared to the students who received standard clinical training.51 In addition, USI

has been proven to be one of the fastest methods to confirm and determine necessary action not

only for injured athletes, but for anesthesia trainees in hospitals learning to intubate and place

endotracheal tubes in the esophagus. The use of US can help guide the trainee and direct them

toward the correct area.52

Electromyography

24

Surface electromyography (sEMG) is another non-invasive way to assess muscles. Clinicians

and researchers are able to study their electrical activity and monitor changes in endurance. Strict

guidelines on musculoskeletal anatomy and proper sensor placement have been defined when

using sEMG.9 Before placement of sensor the skin must be prepared in order to get good to

excellent skin-electrode contact. Then the subject is to be positioned in the recommended posture

for that specific position. Following that the sensor is ready to be placed, it is to be located on a

point that lies between two anatomical landmarks. The specific position and orientation for every

muscle is based on two rules; 1. The sensor is to be placed halfway between the most distal

motor endplate and that tendon that is also located distally, and 2. The sensor is to be placed

within this region and not on the edge to maximize the distance between what is examined and

other muscles.9

EMG and its Connection to USI

The clinical standard when assessing electrical signals from the fibers of muscles and

interpreting their characteristic meaning and underlying pathological changes has always been

needle electromyography.53,54 The use of needle EMG permits inserting a needle into the patients

muscle and putting them at a higher risk of pain, bleeding and even pneumothorax.55 There is

evidence to validate that surface EMG and needle EMG can detect the same activation of

muscles when implemented.56 In the following study they noted the surface EMG and needle

EMG reflected dependable findings, but the surface EMG yielded higher velocity when

measuring the muscle fiber conduction.57

25

Surface EMG and USI have both become an alternative for a subtle less invasive approach and

have been used simultaneously on patients when collecting data. When examining the leg, the

rate of agreement with US and sEMG was maximal, with a median of 30%, for single differential

recordings.53, 58 USI can cooperate with sEMG to achieve a more accurate human machine

interface when looking at finger motion recognition.59 The USI uses a higher resolution to be

able to depict the structural changes of muscles59, while EMG is less sensitive to spatial

arrangment.58

Thickness and Activation

The thickness of muscles has been measured through USI and compared with the electrical

activity during movement and contraction of muscles. The TrA, IO and EO have been studied

using such measures within a healthy population.60 This research showed after three exercises of

a drawing-in maneuver no change was seen throughout the EO and IO muscles, but a change in

thickness and strength of the TrA was seen.60 The drawing in maneuver is understood as the

activation of the transversus abdominus, the deepest muscle, in order to assist in stabilizing the

spine. Subjects are directed to bend knees to a 90-degree angle and lay in a supine position.

While in this position they are instructed to pick a focal point, place their hands on their head and

breathe out while pulling in the navel with continuous pressure.60 The RA is activated during

isometric movements such as supine trunk raise and supine bent leg raise which is seen in the

frequency changes of EMG.61 Using USI researchers compared the muscle thickness of IO, EO,

and TrA after being activated by a forced expiration.62 EO can also be activated when the torso is

being rotated and abducted. A common wat to quantify and measure neuromuscular function of

26

GMAX and GMED is using the central activation ratio (CAR). CAR verifies isometric torque

movements of hip abduction and hip extension activates GMAX and GMED.63

EMG and USI Synchronization

USI and EMG diagnostics are together one of the most often used resources when examining

muscles. Muscle changes seen on the US data were closely linked with the spike changes on the

EMG.64 Systems such as the Teager-Kaiser Energy Operator (TKEO) have been set in place to

capture both the spikes with the images in a synchronized manner.11 The TKEO can detect

motion intensity using an algorithm which is common when using EMG. This motion intensity

can also be seen visually when muscle fascicles are being contracted and then later processed

with TKEO and the onset of the two signals (the EMG and the US) can then be compared.11

However, not having these custom programs to determine the exact timing of activation can

make this process extremely difficult and not allow for them to be integrated into many clinical

care facilities. With the use of M-mode clinicians can see the start and end of muscle activity. A

change in muscle thickness can be witnessed using USI when contraction takes place and during

the same interval as the muscle is activated to contract a spike can be seen on the EMG monitor

due to the excitation of muscle.11

Reliability of Ultrasound

Inter-Rater Reliability

Inter-rater reliability focuses on the consistency between raters or investigators. Intraclass

correlation coefficient (ICC), which measures the reliability using quantitative measures is

27

important when defining reliability. An ICC of 1.0 represents a perfect agreement. Assessment of

the morphologic characteristics at rest and contracted showed good to excellent reliability with

ICC scores all above 0.85 with a 95% confidence interval between novice investigators.5

General investigations of the abdominal muscles and fasciae have determined good reliability of

raters with an ICC score of 0.83 when examining the fasciae and excellent reliability with an

ICC score of 0.99 when using USI to see the muscles.38 Other studies have been conducted using

2D and 3D USI with novice and expert raters when examining the hips of infants. Reliability of

inter-rater was poor for 2D USI, but moderate to high reliability for 3D USI.65 Inter-rater

reliability has overall showed to be a good and highly reliable source in daily clinical routines

when examining the architecture of gastrocnemius muscles.66

Intra-Rater Reliability

Intra-rater reliability is the uniformity between two sessions when conducting the same

investigation with the same rater. TrA, IO, and EO thickness was measured using USI at rest and

during contraction, revealing reliability between sessions.39 Using a single group and repeating

measures using USI, results clearly proved excellent reliability of measures of abdominal

muscles when using the straight leg test with an ICC score of 0.90.39 In the same hip study

mentioned in the earlier section raters examined intra- reliability and discovered accuracy was

higher for 3D USI when compared to the 2D USI.65 Using M-mode to observe intra-rater

reliability when assessing diaphragmatic motion resulted in accurate and reproducible

measurements yielding observer agreement ICC scores of 0.90 and 0.797. 67 In another instance,

two raters used USI to assess the pelvic tilt of healthy individuals and determined reliability to be

good to excellent with ICC scores above 0.86.68 Intra-reliability has been proven to be of feasible

28

and of great clinical use in many other aspects and studies using USI such as on tendons, tissues

and other structures outside of the lumbopelvic hip complex.69,70,71 Although the focus is on the

lumbopelvic-hip complex these muscles and structures outside of the complex are still significant

in that they represent the various ways clinicians can use USI to enhance the body’s ability to

function better as a whole.

29

Overall Significance of Study

Ultrasound imaging in trunk musculature has been investigated with similar methods5, but not

with this type of synchronous muscle activity collection. It must also first be established in a

healthy group of participants before testing in injured individuals and is the first study of its

kind. This study is impactful not only because this specific measurement technique has not been

explored in this manner, but because of the application potential to help clinicians successfully

aid injured patients through their rehabilitation process. The establishment of the reliability of

this technique will allow for synchronous collection of electrical and visual muscle activity

changes of a variety of muscles in the lumbopelvic-hip complex for both novice and experienced

raters.

30

Appendix B: Additional Methods

31

Table B1. IRB Approval Letter

32

Table B1. IRB Approval Letter Cont.

33

Table B2. Health History Form

34

Table B3. Physical Activity Questionnaire

35

Table B3. Physical Activity Questionnaire Cont.

36

Table B4. Global Health Form

37

Table B4. Global Health Form Cont.

38

Table B5. Godin Questionnaire

39

Table B5. Godin Questionnaire Cont.

40

Table B6. Oswestry Disability Index

41

Table B7. Physical Function Form

42

Table B7. Physical Function Form Cont.

43

Table B8. Disability Rating Scale For Low Back Pain

44

Table B9. Tegner Activity Scale

45

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