Jackie L. Whittaker

Ultrasound Characteristics of the Deep Abdominal Muscles During the Active Straight Leg Raise Test

OBJECTIVE To determine whether changes in the transversus abdominis (TrA) and internal oblique (IO) muscles, as seen on ultrasound imaging, during the active straight leg raise (ASLR) test differ between subjects with and without unilateral lumbopelvic pain. DESIGN Cross-sectional, case-control study. SETTING Clinical laboratory. PARTICIPANTS Subjects (n=15) with unilateral symptoms in the lumbopelvic region and age-matched and sex-matched control subjects (n=15). INTERVENTIONS Bilateral measurements of the deep abdominal muscles (TrA and IO) were obtained simultaneously using ultrasound imaging to compare the percent change in muscle thickness from rest with (1) immediately on raising, (2) after a 10-second hold, and (3) within 5 seconds after returning the lower extremity to the plinth. MAIN OUTCOME MEASURE Percent change in muscle thickness of both muscles from rest to the other 3 time intervals during the ASLR test. RESULTS The 3-way group x side measured x time and 2-way side measured x time interactions were not significant for either the TrA (P> or =.34) or the IO (P> or =.14) muscles. The 2-way interaction group x time was significant for both the TrA (P=.003) and the IO (P=.02) muscles. On lifting the lower extremity, the control group demonstrated a 23.7% and 11.2% increase in TrA and IO muscle thickness, respectively, while those with lumbopelvic pain demonstrated a 6.4% and 5.7% increase in TrA and IO muscle thickness, respectively. CONCLUSIONS Although subjects with unilateral lumbopelvic pain demonstrated a smaller increase in muscle thickness, during the ASLR test there appears to be a symmetrical response in both of the deep abdominal muscles regardless of which lower extremity is lifted during the ASLR test or the unilateral nature of the symptoms. This study attests to the potential construct validity of using the ASLR test to assess different motor control strategies of the TrA and IO muscles in subjects with unilateral lumbopelvic pain.

Ultrasound Imaging and Muscle Function

There is a growing trend in the physical therapy profession to use conventional grayscale brightness (B-mode) ultrasound imaging (USI) as a tool to assess the morphological (form and structure) and morphometric (measures of form) characteristics of muscle, and to use these findings to draw conclusions regarding muscle function. This trend is reflected in numerous published investigations. As many physical therapists may lack training in the principles and instrumentation underlying USI use, it is critical that therapists gain a clear understanding of the information that USI can, and cannot, provide about muscle function before employing the technique for either research or clinical applications. Failure to do so may result in the propagation of inaccurate terminology and beliefs. This paper aims to clarify the role that USI has in the assessment of muscle function, first, by briefly reviewing how conventional grayscale B-mode ultrasound images and clips are generated, and second, by summarizing the types of information that these images can provide. It also discusses the various factors that need to be considered when interpreting a dynamic USI assessment of muscle specifically as it relates to the assessment of muscle function.

Changes in Lateral Abdominal Muscle Thickness During the Abdominal Drawing-in Maneuver in Those With Lumbopelvic Pain

STUDY DESIGN Controlled laboratory study. OBJECTIVES To determine if changes in transversus abdominis (TrA) and internal oblique (IO) muscle thickness and side-to-side symmetry differ in individuals with and without unilateral lumbopelvic pain while at rest and during the abdominal drawing-in maneuver (ADIM). BACKGROUND Although the ADIM has been found to produce a symmetrical change in TrA and IO muscle thickness in healthy subjects, how these muscles are activated in those with unilateral lumbopelvic pain during the ADIM remains unknown. METHODS Fifteen subjects with lumbopelvic pain and 15 age- and gender-matched control subjects were recruited. To investigate a similar subgroup of patients with lumbopelvic pain that has been used in previous research, subjects were required to have unilateral symptoms, a positive sacroiliac provocation test, and a positive active straight-leg raise test. Ultrasound images were obtained bilaterally at 2 different points during each trial of the ADIM: (1) at rest and (2) while maintaining the ADIM. Average percent change in thickness of the TrA and IO muscles was obtained over 3 trials. RESULTS The percent change in thickness of the TrA was 20.9% less in those with lumbopelvic pain compared to the control group (P = .035), while the percent change in IO thickness was equivalent between groups (P = .522). No differences were observed for the TrA or IO muscles between the symptomatic and asymptomatic sides in those with (TrA, P = .263; IO, P = .172) or without (TrA, P = .780; IO, P = .635) lumbopelvic pain during the ADIM. Changes in TrA muscle thickness were greater than the IO muscle during the ADIM for both groups (P<.001). Specifically, the increases in TrA muscle thickness in those with and without lumbopelvic dysfunction were 32.7% and 47.3% greater, respectively, compared to changes in the IO muscle. CONCLUSIONS Individuals with unilateral lumbopelvic pain demonstrated a smaller increase in thickness of the TrA muscle during the ADIM. This finding provides an element of construct validity for the use of the ADIM for assessing TrA muscle thickness in those with unilateral lumbopelvic pain. However, both groups demonstrated a symmetrical side-to-side change in TrA and IO muscle thickness despite the symptomatic group having unilateral symptoms. Further, we detected a preferential change in TrA muscle thickness during the ADIM in both groups.

Comparison of the sonographic features of the abdominal wall muscles and connective tissues in individuals with and without lumbopelvic pain.

STUDY DESIGN Cross-sectional, case-control study. OBJECTIVES To measure and compare the resting thickness of the 4 abdominal wall muscles, their associated perimuscular connective tissue (PMCT), and interrecti distance (IRD) in persons with and without lumbopelvic pain (LPP), using ultrasound imaging. BACKGROUND The muscles and PMCT of the abdominal wall assist in controlling the spine. Functional deficits of the abdominal wall muscles have been detected in populations with LPP. Investigations of the abdominal wall in those with LPP are primarily concerned with muscle, most commonly the transversus abdominis (TrA) and internal oblique (IO). Because the abdominal wall functions as a unit, all 4 abdominal muscles and their associated connective tissues should be considered concurrently. METHODS B-mode ultrasound imaging was used to measure the resting thickness of the rectus abdominis (RA), external oblique, IO, and TrA muscles; the PMCT planes; and IRD in 50 male and female subjects, 25 with and 25 without LPP (mean ± SD age, 36.3 ± 9.4 and 46.6 ± 8.0 years, respectively). Univariate correlation analysis was used to identify covariates. Analyses of covariance (ANCOVAs) and the Kruskal-Wallis test (IRD) were used to compare cohorts (α = .05). RESULTS The LPP cohort had less total abdominal muscle thickness (LPP mean ± SD, 18.9 ± 3.0 mm; control, 20.3 ± 3.0 mm; ANCOVA adjusted for body mass index, P = .03), thicker PMCT (LPP, 5.5 ± 0.2 mm; control, 4.3 ± 0.2 mm; ANCOVA adjusted for body mass index, P = .007), and wider IRD (LPP, 11.5 ± 2.0 mm; control, 8.4 ± 1.8 mm; Kruskal-Wallis, P = .005). Analysis of individual muscle thickness revealed no difference in the external oblique, IO, and TrA, but a thinner RA in the LPP cohort (LPP mean ± SD, 7.8 ± 1.5 mm; control, 9.1 ± 1.2 mm; ANCOVA adjusted for body mass index, P<.001). CONCLUSION To our knowledge, this is the first study to investigate the morphological characteristics of all 4 abdominal muscles and PMCT in individuals with LPP. The results suggest that there may be altered loading of the PMCT and linea alba secondary to an altered motor control strategy involving a reduced contribution of the RA. Further, the change in RA and connective tissue morphology may be more evident than changes in external oblique, IO, and TrA thickness in persons with LPP. The causes and functional implications of these changes warrant further investigation, as does the role of the RA muscle in the development and persistence of LPP.

Abdominal Ultrasound Imaging of Pelvic Floor Muscle Function in Individuals with Low Back Pain

Abstract Research reveals that the primary impairment of the muscular system in individuals with low back pain is not one of strength or functional capacity but rather one of motor control of the deep muscles of the trunk. These deep muscles include the transversus abdominis, the deep segmental fibers of lumbar multifidus, the pelvic floor, and the diaphragm. Advances in knowledge regarding load transfer in the lumbopelvic region have provided the orthopaedic manual therapist with the necessary tools to assess most components of lumbopelvic dysfunction with the exclusion of an evaluation technique for pelvic floor motor control. The use of ultrasound imaging to observe the real-time contraction of muscles is a valuable tool, specifically when the muscles of interest are deep and not readily observable. The author proposes a novel abdominal ultrasound imaging method to assess voluntary pelvic floor motor control and discusses the rationale for its application in a population with lumbopelvic dysfunction.

Osteoarthritis: Models for appropriate care across the disease continuum

Osteoarthritis (OA) is a leading cause of pain and disability worldwide. Despite the existence of evidence-based treatments and guidelines, substantial gaps remain in the quality of OA management. There is underutilization of behavioral and rehabilitative strategies to prevent and treat OA as well as a lack of processes to tailor treatment selection according to patient characteristics and preferences. There are emerging efforts in multiple countries to implement models of OA care, particularly focused on improving nonsurgical management. Although these programs vary in content and setting, key lessons learned include the importance of support from all stakeholders, consistent program delivery and tools, a coherent team to run the program, and a defined plan for outcome assessment. Efforts are still needed to develop, deliver, and evaluate models of care across the spectrum of OA, from prevention through end-stage disease, in order to improve care for this highly prevalent global condition.

Association Between Changes in Electromyographic Signal Amplitude and Abdominal Muscle Thickness in Individuals With and Without Lumbopelvic Pain

STUDY DESIGN Validation study. OBJECTIVES To investigate the association between changes in electromyographic (EMG) signal amplitude and sonographic measures of muscle thickness of 4 abdominal muscles, during 2 clinical tests, in adults with and without lumbopelvic pain. BACKGROUND There is a trend in rehabilitation to use ultrasound imaging (USI) to determine the extent of abdominal muscle contraction. However, the literature investigating the relationship between abdominal muscle thickness change and level of activation is inconclusive and has not included clinically relevant tasks. METHODS Simultaneous recording from fine-wire EMG and USI was performed for 4 abdominal muscles, in 7 adults with lumbopelvic pain (mean ± SD age, 29.7 ± 12.0 years) and 7 adults without lumbopelvic pain (32.0 ± 10.6 years), during an active straight leg raise (ASLR) test and an abdominal drawing-in maneuver (ADIM). Cross-correlation functions and linear regression analyses were used to describe the relationship between the 2 measures. Analyses of variance were used to compare individuals with and without lumbopelvic pain, with an alpha set at .05. RESULTS Across all muscles, peak cross-correlation values were low (ASLR, r = 0.28 ± 0.09; ADIM, r = 0.35 ± 0.11), and there was large variability in associated time lags (ASLR, τ = 0.69 ± 2.56 seconds; ADIM, τ = 0.53 ± 3.75 seconds). Regression analyses did not detect a systematic pattern of association between EMG signal amplitude and USI measurements, and analyses of variance revealed no differences between cohorts. CONCLUSION These results suggest a weak relationship between EMG amplitude and abdominal muscle thickness change measured with USI during the ADIM and ASLR, and raise questions about thickness change derived from USI as a measure of muscular activity for the abdominal musculature.

Sonographic Measures of the Gluteus Medius, Gluteus Minimus, and Vastus Medialis Muscles

STUDY DESIGN Intrarater, repeated-measures, within-session reliability study. OBJECTIVE To describe a standardized method and preliminary reliability estimates for sonographic measures of resting and contracted gluteus medius (GMd), gluteus minimus (GMn), and resting vastus medialis (VM) muscles. BACKGROUND Sonography has been used to assess the morphology of a diversity of muscles in relation to a variety of musculoskeletal dysfunctions. Although the GMd, GMn, and VM muscles are associated with dysfunctions such as patellofemoral pain and osteoarthritis, there is a paucity of information regarding protocols for sonographic measurements of these muscles. METHODS A standardized method was developed and used to gather sonographic measures of resting and contracted (sidelying hip abduction task) GMd and GMn thickness and resting VM cross-sectional area during 1 measurement session in 29 female soccer players 14 to 17 years of age. RESULTS Intrarater reliability values for ultrasound imaging measurements of resting, contracted, and change during contraction (intraclass correlation coefficient model 3,3 [ICC3,3]) of the GMd were 0.98 (95% confidence interval [CI]: 0.97, 0.99), 0.98 (95% CI: 0.96, 0.99), and 0.84 (95% CI: 0.71, 0.92), respectively, and of the GMn were 0.98 (95% CI: 0.97, 0.99), 0.94 (95% CI: 0.88, 0.97), and 0.53 (95% CI: 0.21, 0.76), respectively. Reliability (ICC3,3) for resting VM cross-sectional area was 0.99 (95% CI: 0.99, 0.99). Standard error of measurement for GMd, GMn, and VM varied between 0.5 and 1.6 mm, 0.3 and 1.4 mm, and 0.4 cm2, respectively, and 95% minimal detectable change ranged from 0.8 to 4.5 mm for the gluteals and 0.4 to 0.5 cm2 for the VM. CONCLUSION Reliable sonographic measurements of the lateral hip and knee musculature at rest and during contraction are feasible. Further investigation is required to establish the generalizability and reproducibility of the protocols presented in this report.

Higher Fat Mass Is Associated With a History of Knee Injury in Youth Sport

• STUDY DESIGN: Historical cohort study. • BACKGROUND: History of a knee joint injury and increased fat mass are risk factors for joint disease. • OBJECTIVE: The objective of this study was to examine differences in adiposity, physical activity, and cardiorespiratory fitness between youths with a 3‐ to 10‐year history of sport‐related intraarticular knee injury and uninjured controls. • METHODS: One hundred young adults (aged 15‐26 years; 55% female) with a sport‐related intra‐articular knee injury sustained 3 to 10 years previously and 100 controls matched for age, sex, and sport, who had no history of intra‐articular knee injury, were recruited. Fat mass index (FMI) and abdominal fat (fat mass at the L1 to L4 vertebral levels) were derived using dual‐energy X‐ray absorptiometry. Physical activity and cardiorespiratory fitness were measured using the Godin Leisure‐Time Exercise Questionnaire and the multistage 20‐meter shuttle run test for aerobic fitness, respectively. • RESULTS: Previously injured participants demonstrated higher FMI (within‐pair difference, 1.05 kg/m2; 95% confidence interval [CI]: 0.53, 1.57) and abdominal fat (461 g; 95% CI: 228, 694) than uninjured controls. In multivariable linear regression analysis, previous injury was significantly associated with increased FMI. This increase was attenuated in those who participated in higher levels of physical activity or had higher estimated maximum volume of oxygen. • CONCLUSION: As a risk factor for osteoarthritis in an already susceptible group, excess adiposity is an undesirable trait in the potential pathway to joint disease. Increasing physical activity in this population may be a potential intervention to reduce adiposity thus impede disease initiation and/or progression. • LEVEL OF EVIDENCE: Level 2b.

Predicting sport and occupational lower extremity injury risk through movement quality screening: a systematic review

Background Identification of risk factors for lower extremity (LE) injury in sport and military/first-responder occupations is required to inform injury prevention strategies. Objective To determine if poor movement quality is associated with LE injury in sport and military/first-responder occupations. Materials and methods 5 electronic databases were systematically searched. Studies selected included original data; analytic design; movement quality outcome (qualitative rating of functional compensation, asymmetry, impairment or efficiency of movement control); LE injury sustained with sport or military/first-responder occupation. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were followed. 2 independent authors assessed the quality (Downs and Black (DB) criteria) and level of evidence (Oxford Centre of Evidence-Based Medicine model). Results Of 4361 potential studies, 17 were included. The majority were low-quality cohort studies (level 4 evidence). Median DB score was 11/33 (range 3–15). Heterogeneity in methodology and injury definition precluded meta-analyses. The Functional Movement Screen was the most common outcome investigated (15/17 studies). 4 studies considered inter-relationships between risk factors, 7 reported diagnostic accuracy and none tested an intervention programme targeting individuals identified as high risk. There is inconsistent evidence that poor movement quality is associated with increased risk of LE injury in sport and military/first-responder occupations. Conclusions Future research should focus on high-quality cohort studies to identify the most relevant movement quality outcomes for predicting injury risk followed by developing and evaluating preparticipation screening and LE injury prevention programmes through high-quality randomised controlled trials targeting individuals at greater risk of injury based on screening tests with validated test properties.