Muscles In People Research Articles

Convolutional neural networks for the automatic segmentation of lumbar paraspinal muscles in people with low back pain

The size, shape, and composition of paraspinal muscles have been widely reported in disorders of the cervical and lumbar spine. Measures of size, shape, and composition have required time-consuming and rater-dependent manual segmentation techniques. Convolutional neural networks (CNNs) provide alternate timesaving, state-of-the-art performance measures, which could realise clinical translation. Here we trained a CNN for the automatic segmentation of lumbar paraspinal muscles and determined the impact of CNN architecture and training choices on segmentation performance. T2-weighted MRI axial images from 76 participants (46 female; age (SD): 45.6 (12.8) years) with low back pain were used to train CNN models to segment the multifidus, erector spinae, and psoas major muscles (left and right segmented separately). Using cross-validation, we compared 2D and 3D CNNs with and without data augmentation. Segmentation accuracy was compared between the models using the Sørensen-Dice index as the primary outcome measure. The effect of increasing network depth on segmentation accuracy was also investigated. Each model showed high segmentation accuracy (Sørensen-Dice index ≥ 0.885) and excellent reliability (ICC2,1 ≥ 0.941). Overall, across all muscles, 2D models performed better than 3D models (p = 0.012), and training without data augmentation outperformed training with data augmentation (p < 0.001). The 2D model trained without data augmentation demonstrated the highest average segmentation accuracy. Increasing network depth did not improve accuracy (p = 0.771). All trained CNN models demonstrated high accuracy and excellent reliability for segmenting lumbar paraspinal muscles. CNNs can be used to efficiently and accurately extract measures of paraspinal muscle health from MRI.

An sEMG-Controlled Forearm Bracelet for Assessing and Training Manual Dexterity in Rehabilitation: A Systematic Review.

Background: The ability to perform activities of daily living (ADL) is essential to preserving functional independence and quality of life. In recent years, rehabilitation strategies based on new technologies, such as MYO Armband®, have been implemented to improve dexterity in people with upper limb impairment. Over the last few years, many studies have been published focusing on the accuracy of the MYO Armband® to capture electromyographic and inertial data, as well as the clinical effects of using it as a rehabilitation tool in people with loss of upper limb function. Nevertheless, to our knowledge, there has been no systematic review of this subject. Methods: A systematically comprehensive literature search was conducted in order to identify original studies that answered the PICO question (patient/population, intervention, comparison, and outcome): What is the accuracy level and the clinical effects of the MYO Armband® in people with motor impairment of the upper limb compared with other assessment techniques or interventions or no intervention whatsoever? The following data sources were used: Pubmed, Scopus, Web of Science, ScienceDirect, Physiotherapy Evidence Database, and the Cochrane Library. After identifying the eligible articles, a cross-search of their references was also completed for additional studies. The following data were extracted from the papers: study design, disease or condition, intervention, sample, dosage, outcome measures or data collection procedure and data analysis and results. The authors independently collected these data following the CONSORT 2010 statement when possible, and eventually reached a consensus on the extracted data, resolving disagreements through discussion. To assess the methodological quality of papers included, the tool for the critical appraisal of epidemiological cross-sectional studies was used, since only case series studies were identified after the search. Additionally, the articles were classified according to the levels of evidence and grades of recommendation for diagnosis studies established by the Oxford Center for Evidence-Based Medicine. Also, The Cochrane Handbook for Systematic Reviews of Interventions was used by two independent reviewers to assess risk of bias, assessing the six different domains. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was followed to carry out this review. Results: 10 articles with a total 180 participants were included in the review. The characteristics of included studies, sample and intervention characteristics, outcome measures, the accuracy of the system and effects of the interventions and the assessment of methodological quality of the studies and risk of bias are shown. Conclusions: Therapy with the MYO Armband® has shown clinical changes in range of motion, dexterity, performance, functionality and satisfaction. It has also proven to be an accurate system to capture signals from the forearm muscles in people with motor impairment of the upper limb. However, further research should be conducted using bigger samples, well-defined protocols, comparing with control groups or comparing with other assessment or therapeutic tools, since the studies published so far present a high risk of bias and low level of evidence and grade of recommendation.

Feasibility and reliability of measuring muscle stiffness in Parkinson's Disease using MyotonPRO device in a clinical setting in Ghana.

To examine the feasibility and within-session reliability of Myoton technology to measure muscle stiffness objectively in people with Parkinson's disease in an outpatient setting. An exploratory quantitative study design was used. The study was conducted in the outpatient physiotherapy department of a Teaching Hospital in Ghana. Participants were recruited from three sites. Thirty adults with Parkinson's disease over 18 years with increased tone (muscle stiffness) and at Hoehn and Yahr Stages I-III were studied. Persons with severe comorbidities were excluded. There was no intervention before testing. The MyotonPRO device measured the mechanical properties of the biceps brachii, flexor carpi radialis and tibialis anterior muscles in a relaxed supine position. The probe applied mechanical impulses to the skin, eliciting tissue oscillations. The muscles' three parameters (stiffness, non-neural tone and elasticity) were recorded bilaterally. The reliability of two sets (of 5 impulses) of Myoton data on all three muscles was examined. All 30 participants (66.3±8.9 years) were recruited and tested within eight weeks. Intraclass correlation coefficients (ICC 3,2) were above 0.92 for biceps brachii and tibialis anterior and above 0.86 for flexor carpi radialis. The MyotonPRO was reliable for measuring two sets of data within the same session, indicating that only one set of measurements is needed. The technique is feasible and easy to use in a clinical setting in Ghana, with the potential to assess the effect of medical and physiotherapy interventions on muscles in people with Parkinson's disease. M.S discloses a grant from the Science and Technology Facilities Council Impact Acceleration Account at the University of Southampton to support this collaborative research (no personal finance received). All other authors, M.W.A, P.E.M, C.O.Y, B.E.A.S, S.A.-B, and A.A have no financial disclosure.

Effect of Electrical Stimulation Followed by Exercises in Postnatal Diastasis Recti Abdominis via MMP2 Gene Expression.

Since abdominal muscle training is one of the most important ways to treat rectal diastasis, it is necessary to design and provide appropriate exercises to treat this problem. One of the complementary methods to achieve higher intensity training is the use of electrical muscle stimulation along with voluntary activity, which causes maximum recall in muscle units. Therefore, in the current study, the effect of electrical stimulation followed by exercises was evaluated in postnatal diastasis recti abdominis via MMP2 gene expression. For this purpose, we studied on thirty-two women who had rectal diastasis for six months and were referred to a physiotherapy clinic by a gynecologist. They were divided into the control group (n=16) and the intervention group (n=16). The distance between the two blocks of the rectus abdominis muscle and the thickness of the abdominal muscles at rest was determined by ultrasound. In the intervention group, electrical stimulation and strengthening exercises of oblique muscles were performed for six weeks. The control group did not perform any specific exercises. After six weeks, another ultrasound was performed. The expression of the MMP2 gene was measured by the real-time PCR method. Comparison of the distance between the two blocks of rectus abdominis muscle (above the umbilicus and below the umbilicus) before and after six weeks showed that in the experimental group after intervention in both areas had a significant decrease (above the umbilicus = 0.001 and below the umbilicus P = 0.03), while this distance in the control group did not decrease significantly (p >0.05). Also, in the upper part of the umbilicus, the distance between the two rectus abdominis muscle blocks in two groups after the intervention showed a significant difference (p = 0.04). Evaluation of MMP2 gene expression showed that there was no significant difference between the two groups before the intervention (p >0.05). However, after the intervention, the expression of this gene decreased significantly in the intervention group (p = 0.007). In general, the present study results showed that electrical stimulation of abdominal muscles with strengthening exercises of internal and external oblique muscles could reduce rectal diastasis and increase the thickness of these muscles in people with rectal diastasis.

Chiropractic Spinal Adjustment Increases the Cortical Drive to the Lower Limb Muscle in Chronic Stroke Patients.

This study aimed to investigate the effects of a single session of chiropractic spinal adjustment on the cortical drive to the lower limb in chronic stroke patients. In a single-blinded, randomized controlled parallel design study, 29 individuals with chronic stroke and motor weakness in a lower limb were randomly divided to receive either chiropractic spinal adjustment or a passive movement control intervention. Before and immediately after the intervention, transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) were recorded from the tibialis anterior (TA) muscle of the lower limb with the greatest degree of motor weakness. Differences in the averaged peak-peak MEP amplitude following interventions were calculated using a linear regression model. Chiropractic spinal adjustment elicited significantly larger MEP amplitude (pre = 0.24 ± 0.17 mV, post = 0.39 ± 0.23 mV, absolute difference = +0.15 mV, relative difference = +92%, p < 0.001) compared to the control intervention (pre = 0.15 ± 0.09 mV, post = 0.16 ± 0.09 mV). The results indicate that chiropractic spinal adjustment increases the corticomotor excitability of ankle dorsiflexor muscles in people with chronic stroke. Further research is required to investigate whether chiropractic spinal adjustment increases dorsiflexor muscle strength and walking function in people with stroke.

Increased trunk flexion may underlie elevated knee flexor activity in people with knee osteoarthritis

BackgroundPrevious research has demonstrated elevated activation of the knee flexor muscles in people with knee osteoarthritis. People with this condition have also been observed to walk with increased trunk flexion; this may alter biomechanical loading patterns and change muscle activation profiles. Therefore, the aim of this study was to understand the biomechanical effect of increasing trunk flexion during walking. MethodsKinetic and EMG data were collected from a sample of 20 people with knee osteoarthritis and a sample of 20 healthy matched controls during normal walking. Using a biofeedback protocol, participants were subsequently instructed to walk with a 5° increase in trunk flexion. Sagittal moments, muscle activations and co-contractions were then compared across a window in early stance with a two-way ANOVA test. ResultsWhen trunk flexion was increased, there was a corresponding increase in activity of the medial and lateral hamstrings and gastrocnemius muscles as well as a rise in medial co-contraction. This effect was consistent across the two groups. The most pronounced effect was observed for semitendinosus, which showed a dramatic change in activation profile in the healthy group and a 127% increase in activation during early stance. ConclusionsThis is the first study to demonstrate that increased trunk flexion in people with knee osteoarthritis may explain, to some degree, the elevated knee flexor activity and medial co-contraction which is associated with this disease. These findings motivate further work to understand the therapeutic potential of interventions designed to improve postural alignment.

Does Motor Control Exercise Restore Normal Morphology of Lumbar Multifidus Muscle in People with Low Back Pain? - A Systematic Review.

Aberrant morphological changes in lumbar multifidus muscle (LMM) are prevalent among patients with low back pain (LBP). Motor control exercise (MCE) aims to improve the activation and coordination of deep trunk muscles (eg, LMM), which may restore normal LMM morphology and reduce LBP. However, its effects on LMM morphology have not been summarized. This review aimed to summarize evidence regarding the (1) effectiveness of MCE in altering LMM morphometry and decreasing LBP; and (2) relations between post-MCE changes in LMM morphometry and LBP/LBP-related disability. Cumulative Index to Nursing and Allied Health Literature, MEDLINE, Cochrane Central Register of Controlled Trials, the Physiotherapy Evidence Database, EMBASE and SPORTDiscus were searched from inception to 30 September 2020 to identify relevant randomized controlled trials. Two reviewers independently screened articles, extracted data, and evaluated risk of bias and quality of evidence. Four hundred and fifty-one participants across 9 trials were included in the review. Very low-quality evidence supported that 36 sessions of MCE were better than general physiotherapy in causing minimal detectable increases in LMM cross-sectional areas of patients with chronic LBP. Very low- to low-quality evidence suggested that MCE was similar to other interventions in increasing resting LMM thickness in patients with chronic LBP. Low-quality evidence substantiated that MCE was significantly better than McKenzie exercise or analgesics in increasing contracted LMM thickness in patients with chronic LBP. Low-quality evidence corroborated that MCE was not significantly better than other exercises in treating people with acute/chronic LBP. Low-quality evidence suggested no relation between post-MCE changes in LMM morphometry and LBP/LBP-related disability. Collectively, while MCE may increase LMM dimensions in patients with chronic LBP, such changes may be unrelated to clinical outcomes. This raises the question regarding the role of LMM in LBP development/progression.

Walking Exercise Therapy Effects on Lower Extremity Skeletal Muscle in Peripheral Artery Disease.

Walking exercise is the most effective noninvasive therapy that improves walking ability in peripheral artery disease (PAD). Biologic mechanisms by which exercise improves walking in PAD are unclear. This review summarizes evidence regarding effects of walking exercise on lower extremity skeletal muscle in PAD. In older people without PAD, aerobic exercise improves mitochondrial activity, muscle mass, capillary density, and insulin sensitivity in skeletal muscle. However, walking exercise increases lower extremity ischemia in people with PAD, and therefore, mechanisms by which this exercise improves walking may differ between people with and without PAD. Compared with people without PAD, gastrocnemius muscle in people with PAD has greater mitochondrial impairment, increased reactive oxygen species, and increased fibrosis. In multiple small trials, walking exercise therapy did not consistently improve mitochondrial activity in people with PAD. In one 12-week randomized trial of people with PAD randomized to supervised exercise or control, supervised treadmill exercise increased treadmill walking time from 9.3 to 15.1 minutes, but simultaneously increased the proportion of angular muscle fibers, consistent with muscle denervation (from 7.6% to 15.6%), while angular myofibers did not change in the control group (from 9.1% to 9.1%). These findings suggest an adaptive response to exercise in PAD that includes denervation and reinnervation, an adaptive process observed in skeletal muscle of people without PAD during aging. Small studies have not shown significant effects of exercise on increased capillary density in lower extremity skeletal muscle of participants with PAD, and there are no data showing that exercise improves microcirculatory delivery of oxygen and nutrients in patients with PAD. However, the effects of supervised exercise on increased plasma nitrite abundance after a treadmill walking test in people with PAD may be associated with improved lower extremity skeletal muscle perfusion and may contribute to improved walking performance in response to exercise in people with PAD. Randomized trials with serial, comprehensive measures of muscle biology, and physiology are needed to clarify mechanisms by which walking exercise interventions improve mobility in PAD.

Electromyographic Analysis of Gluteus Medius Activity in People with Non-Specific Chronic Low Back Pain Compared to Healthy Controls

Background and Objectives: The functioning of the hip and trunk muscles has an effect on low backregion. Gluteus medius (Gmed) being the primary hip abductor plays a significant role in maintaining thestability of the pelvis. Despite the significance, this muscle activity is least addressed and is also thoughtto be one among the major causes of pain in the low back. The aim of the study was to compare theactivity of Gmed in non-specific chronic low back pain (NSCLBP) and healthy individuals using SurfaceElectromyography (SEMG).Methods: 506 subjects were screened, of which 200 subjects were selected. Group A: NSCLBP (n=100)and GROUP B: Healthy controls (n=100). Both groups were instructed to perform maximum voluntarycontractions. The mean root mean square (RMS) value of Gmed muscle activity for the exercise task wasrecorded and analyzed using SEMG.Results: The results demonstrated that the mean RMS value of the right Gmed muscle activity for GROUPA was lesser (53.00 ± 24.81) than GROUP B (87.9 ± 37.47). The mean RMS value of the left Gmed activitywas also lesser for GROUP A (55.99 ± 27.21) compared to GROUP B (89.72 ± 39.83). The difference inmeans between the two groups showed highly significant outcome (P<0.001).Conclusion: The study concluded that the muscle activity of Gmed between the groups was lesser in GroupA compared to Group B indicating differential activation of the muscle in people with NSCLBP. However,there was no significant difference in mean RMS value of the right and left Gmed muscle activity whencompared within the groups respectively.

Multifidus Muscle Fiber Type Distribution is Changed in Mouse Models of Chronic Intervertebral Disc Degeneration, but is not Attenuated by Whole Body Physical Activity.

Case-controlled animal study. The aim of this study was to investigate whether multifidus muscle fiber type distribution changes in models of interverbal disc (IVD) degeneration and whether this is resolved by physical activity (PA). The loss of slow type I muscle fibers in the multifidus muscle in people with low back pain is contentious. Data from animal models of IVD degeneration suggest some discrepancies in human studies might be explained by the dependence of slow muscle fiber changes and their underlying mechanisms, on the time since injury and progression of IVD degeneration. It is not yet resolved what changes are apparent once the chronic phase is established. It is also not known whether muscle fiber changes can be resolved by whole body PA. This study aimed to examine slow fiber distribution in the multifidus muscle in models of IVD injury or spontaneous degeneration in animals with or without exposure to PA. Two models of IVD degeneration were used. The first model used a genetically modified mouse (SPARC-null) that spontaneously develops IVD degeneration. The second model involved a surgically induced IVD lesion to induce degeneration. Mice in each study were allocated to housing with or without a running wheel for PA. At 12 months of age, the multifidus muscle was harvested. Slow muscle fiber distribution and the mRNA expression of genes associated with muscle fiber type transformation were examined. The proportion and cross-sectional area of slow muscle fibers were reduced in both models of IVD degeneration compared to controls, without evidence of ongoing fiber transformation. Whole-body PA did not attenuate these alterations. Results confirmed slow muscle fiber loss in the multifidus in the chronic phase of IVD degeneration induced spontaneously and by injury. Whole-body PA did not attenuate changes to muscle fiber distribution. More specific approaches to muscle activation might be required to achieve more complete reversal of muscle fiber changes, with potential implications for therapy in humans.Level of Evidence: N/A.

Abdominal Expansion versus Abdominal Drawing-In Strategy on Thickness and Electromyography of Lumbar Stabilizers in People with Nonspecific Low Back Pain: A Cross-Sectional Study.

The abdominal expansion (AE) strategy, involving eccentric contraction of the abdominal muscles, has been increasingly used in clinical practices; however, its effects have not been rigorously investigated. This study aimed to investigate the immediate effects of the AE versus abdominal drawing-in (AD) strategy on lumbar stabilization muscles in people with nonspecific low back pain (LBP). Thirty adults with nonspecific LBP performed the AE, AD, and natural breathing (NB) strategies in three different body positions. Ultrasonography and surface electromyography (EMG) were, respectively, used to measure the thickness and activity of the lumbar multifidus and lateral abdominal wall muscles. The AE and AD strategies showed similar effects, producing higher EMG activity in the lumbar multifidus and lateral abdominal wall muscles when compared with the NB strategy. All muscles showed higher EMG activity in the quiet and single leg standing positions than in the lying position. Although the AE and AD strategies had similar effects on the thickness change of the lumbar multifidus muscle, the results of thickness changes of the lateral abdominal muscles were relatively inconsistent. The AE strategy may be used as an alternative method to facilitate co-contraction of lumbar stabilization muscles and improve spinal stability in people with nonspecific LBP.

Peak Forces and Force Generating Capacities of Lower Extremity Muscles During Dynamic Tasks in People With and Without Chronic Ankle Instability

ABSTRACT People with chronic ankle instability (CAI) exhibit neuromuscular deficits. However, no study has investigated deficits in forces or force-generating capacities of individual muscles in people with CAI during dynamic tasks. Therefore, the purpose of this study was to estimate and compare peak forces and force-generating capacities of individual muscles during dynamic tasks in people with CAI and healthy controls (CON). Eleven people with CAI and eleven CON performed landing, anticipated cutting, and unanticipated cutting as motion capture, force plate, and electromyography data were recorded. A musculoskeletal model was used to estimate the force and force-generating capacity of lower extremity muscles. People with CAI exhibited greater gluteus maximus force and force-generating capacity than CON during all tasks. In addition, people with CAI exhibited greater force-generating capacity of the vastii muscles than CON during the unanticipated cutting task. These findings suggest that, during dynamic tasks, people with CAI exhibit a neuromuscular control strategy that is characterised by differences in peak forces and force-generating capacities of proximal muscles, which may allow them to compensate for previously described deficits in distal muscles.

Variability of Corticospinal Excitability for the Ankle Dorsiflexor Tibialis Anterior Muscle in People with and Without Incomplete Spinal Cord Injury

Variability of Corticospinal Excitability for the Ankle Dorsiflexor Tibialis Anterior Muscle in People with and Without Incomplete Spinal Cord Injury

Skeletal Muscle Pathology in Peripheral Artery Disease: A Brief Review.

This brief review summarizes current evidence regarding lower extremity peripheral artery disease (PAD) and lower extremity skeletal muscle pathology. Lower extremity ischemia is associated with reduced calf skeletal muscle area and increased calf muscle fat infiltration and fibrosis on computed tomography or magnetic resonance imaging. Even within the same individual, the leg with more severe ischemia has more adverse calf muscle characteristics than the leg with less severe ischemia. More adverse computed tomography-measured calf muscle characteristics, such as reduced calf muscle density, are associated with higher rates of mobility loss in people with PAD. Calf muscle in people with PAD may also have reduced mitochondrial activity compared with those without PAD, although evidence is inconsistent. Muscle biopsy document increased oxidative stress in PAD. Reduced calf muscle perfusion, impaired mitochondrial activity, and smaller myofibers are associated with greater walking impairment in PAD. Preliminary evidence suggests that calf muscle pathology in PAD may be reversible. In a small uncontrolled trial, revascularization improved both the ankle-brachial index and mitochondrial activity, measured by calf muscle phosphocreatine recovery time. A pilot clinical trial showed that cocoa flavanols increased measures of myofiber health, mitochondrial activity, and capillary density while simultaneously improving 6-minute walk distance in PAD. Calf muscle pathological changes are associated with impaired walking performance in people with PAD, and interventions that both increase calf perfusion and improve calf muscle health are promising therapies to improve walking performance in PAD.

Effectiveness of functional training in improving function of facial muscles in people with facial palsy due to trauma

Background: This study aimed to examine the effects of a functional training in improving function of facial muscles in people with facial palsy due to trauma. Settings and Design: Saveetha Physiotherapy OPD, Two group pre-test post-test non-equivalent design. Methods: 20 participants based on convenient sampling were assigned to either receive Functional training group or conventional treatment group. The primary outcome measures are House Brackman score and facial disability index (FDI). Statistical analysis used: Mann Whitney U test was used to compare the data sets between the groups. Results: Between group analysis of post-test mean and standard deviation for House-Brackman score for Func-tional training group and conventional treatment were 1.6(1) and 3.67(0.72) respectively. It was statistically significant with p&lt;0.05.Between group analysis for FDI were statistically significant with p=0.01 at the end of 4 weeks for both subscales of physical and social. Conclusions: Functional training may improve function of facial muscles and can be recommended for people affected with facial palsy due to trauma. Keywords: functional training, traumatic facial palsy, facial exercises, recovery of function, facial rehabilitation, FDI, House-Brackman, Task training

Effectiveness of functional training in improving function of facial muscles in people with facial palsy due to trauma

Effectiveness of functional training in improving function of facial muscles in people with facial palsy due to trauma

Greater fatigue resistance of dorsiflexor muscles in people with prediabetes than type 2 diabetes

Although exercise can prevent progression to T2D among people with prediabetes, little is known about fatigue during exercise in people with prediabetes compared to T2D. The purpose of the study was to compare the magnitude and mechanisms of fatigability of the ankle dorsiflexor muscles between people with prediabetes and T2D. Ten people with prediabetes (6 females, 51.7 ± 6.9 years) and fourteen with T2D (6 females, 52.6 ± 6.2 years) who were matched for age, body mass index and physical activity performed an intermittent (6 s contraction: 4 s relaxation) fatiguing task at 75% maximal voluntary contraction (MVC) with the dorsiflexors. Electrical stimulation was used to assess contractile properties of the dorsiflexor muscles before and after the fatiguing task. People with prediabetes had a longer time-to-task failure, i.e. greater fatigue resistance (7.9 ± 5.1 vs. 4.9 ± 2.5 min, P = 0.04), and slower rate of decline of the (potentiated) twitch amplitude (6.5 ± 3.1 vs. 16.5 ± 11.7%·min−1, P = 0.03) than people with T2D. Shorter time-to-task failure (i.e. greater fatigability) was associated with greater baseline MVC torque (r2 = 0.21, P = 0.02) and faster rate of decline of twitch amplitude (r2 = 0.39, P = 0.04). The ankle dorsiflexor muscles of males and females with prediabetes were more fatigue resistant than people with T2D, and fatigability was associated with contractile mechanisms.

Residual Innervation of the Pelvic Floor Muscles in People with Motor-Complete Spinal Cord Injury.

Individuals classified clinically as having a motor-complete spinal cord injury (mcSCI) should lack voluntary motor function below their injury level. Neurophysiological assessments using electromyography (EMG) and transcranial magnetic stimulation (TMS), however, have demonstrated that persons with mcSCI retain limited cortical descending innervation and voluntary activation of muscles below their level of injury, including muscles of the trunk and lower limb. We explored the possibility of whether there is also preserved innervation of the pelvic floor muscles (PFM) in persons with mcSCI. The PFM are controlled by widespread cortical and subcortical areas and typically coactivated with trunk and gluteal muscles to maintain continence and regulate intra-abdominal pressure. Nine mcSCI and eight control subjects participated in this cross-sectional study. Surface EMG was used to record activity in the PFM. Data were recorded while participants attempted various maneuvers of the trunk and pelvis. We also applied TMS at incrementing levels of intensity over the primary motor cortex area to record motor evoked potentials (MEPs) in the PFM. When performing the maneuvers, activation of the PFM was possible in all controls and the majority of SCI participants. However, the PFM were only activated in the SCI participants during maneuvers that engaged other trunk muscles, however. MEP responses in the PFM were also elicited in all controls and SCI participants, but MEP response characteristics were significantly altered in the SCI group. Our results suggest that persons with mcSCI retain some residual innervation of the PFM after injury, possibly via indirect cortical descending pathways.

Magnetic Resonance Imaging Studies in Duchenne Muscular Dystrophy: Linking Findings to the Physical Therapy Clinic

Duchenne muscular dystrophy (DMD) is a muscle degenerative disorder that manifests in early childhood and results in progressive muscle weakness. Physical therapists have long been an important component of the multidisciplinary team caring for people with DMD, providing expertise in areas of disease assessment, contracture management, assistive device prescription, and exercise prescription. Over the last decade, magnetic resonance imaging of muscles in people with DMD has led to an improved understanding of the muscle pathology underlying the clinical manifestations of DMD. Findings from magnetic resonance imaging (MRI) studies in DMD, paired with the clinical expertise of physical therapists, can help guide research that leads to improved physical therapist care for this unique patient population. The 2 main goals of this perspective article are to (1) summarize muscle pathology and disease progression findings from qualitative and quantitative muscle MRI studies in DMD and (2) link MRI findings of muscle pathology to the clinical manifestations observed by physical therapists with discussion of any potential implications of MRI findings on physical therapy management.

Comparison of Ultrasonic Thickness of Masseter Muscle Between Individuals With and Without Severe Forward Head Posture: A Cross-Sectional Study

ObjectiveIn this cross-sectional descriptive-analytical study, we sought to compare the ultrasonic thickness of the masseter muscle in people with severe forward head posture vs people without forward head posture, and to determine sex differences in muscle thickness. MethodsThirty-eight volunteers (19 with normal head postures and 19 with severe forward head postures), aged 18 to 35 years, entered the study. The severity of the forward head posture was measured by a plumb line and the craniovertebral angle drawn on the recorded images. Based on the recorded images, the masseter muscle thickness was also measured by a 7.5-MHz linear transducer using an ultrasound device in the seated position with 3 mouth positions (closed, half open, and fully open). ResultsThe results showed that the head posture affects masseter thickness significantly (P = .01), with masseter thickness significantly lower in the participants without severe forward head postures compared to those with severe forward head postures in the closed, half-open, and fully open mouth positions (P < .05). Comparing the mean masseter thickness across sexes showed that the masseter muscle is significantly thicker in men compared to women (P = .01). ConclusionHead posture and thickness of the masseter muscle are linked, as the masseter muscle was thicker in all 3 positions in the participants with severe forward head postures.