Complex patterns of gene flow and convergence in the evolutionary history of the spiral-horned antelopes (Tragelaphini).

The Tragelaphini, also known as spiral-horned antelope, is a phenotypically diverse mammalian tribe comprising a single genus, Tragelaphus. The evolutionary history of this tribe has attracted the attention of taxonomists and molecular geneticists for decades because its diversity is characterised by conflicts between morphological and molecular data as well as between mitochondrial, nuclear and chromosomal DNA. These inconsistencies point to a complex history of ecological diversification, coupled by either phenotypic convergence or introgression. Therefore, to unravel the phylogenetic relationships among spiral-horned antelopes, and to further investigate the role of divergence and gene flow in trait evolution, we sequenced genomes for all nine accepted species of the genus Tragelaphus, including a genome each for the highly divergent bushbuck lineages (T. s. scriptus and T. s. sylvaticus). We successfully reconstructed the Tragelaphus species tree, providing genome-level support for the early Pliocene divergence and monophyly of the nyala (T. angasii) and lesser kudu (T. imberbis), the monophyly of the two eland species (T. oryx and T. derbianus) and, importantly, the monophyly of kéwel (T. s. scriptus) and imbabala (T. s. sylvaticus) bushbuck. We found strong evidence for gene flow in at least four of eight nodes on the species tree. Among the six phenotypic traits assessed here, only habitat type mapped onto the species tree without homoplasy, showing that trait evolution was the result of complex patterns of divergence, introgression and convergent evolution.

Expectations of a new eating disorder treatment and its delivery: Perspectives of patients and new therapists.

BACKGROUND: A significant number of people with bulimia nervosa (BN) or binge-eating disorder (BED) do not seek professional help. Important reasons include limited knowledge of eating disorders (EDs), feelings of shame, treatment costs, and restricted access to specialized healthcare. In this study, we explored if a novel therapy delivered in a primary care setting could overcome these barriers. We investigated factors such as motivation and expectations and included the patients' and newly trained therapists' perspectives. METHOD: We interviewed 10 women with BN (n = 2) or BED (n = 8), enrolled in the Physical Exercise and Dietary therapy (PED-t) program, in a Healthy Life Center (HLC) located in a primary healthcare facility. Interview topics discussed were motivations for and expectations of therapy, and the treatment location. In addition, 10 therapists from HLC's were interviewed on their experiences with the PED-t training program and expectations of running PED-t within their service. The semi-structured interviews were analyzed using reflexive thematic analysis. RESULTS: Most patients had limited knowledge about EDs and first realized the need for professional help after learning about PED-t. Patients exhibited strong motivations for treatment and a positive perception of both the PED-t, the new treatment setting, and the therapists' competencies. The therapists, following a brief training program, felt confident in their abilities to treat EDs and provide PED-t. With minor operational adjustments, PED-t can seamlessly be integrated into national HLC service locations. CONCLUSION: PED-t is an accessible therapeutic service that can be delivered in a primary care environment in a stepped-care therapy model. PUBLIC SIGNIFICANCE: This study investigates the views and experiences of patients and newly trained therapists of PED-t (Physical Exercise and Dietary therapy), a new program-led primary care therapy for binge-eating spectrum eating disorders. The treatment and the locations for the intervention, that is, local health care centers, were found to be highly acceptable to both patients and therapists, thus PED-t could easily be integrated as a first step into a step-care delivery model.

Dual-Energy X-Ray Absorptiometry Does Not Confirm Validity of the Craig's Test.

The Craig's test is a clinical assessment used to quantify femoral version. The validity of the Craig's test has been called into question due to instances where the test exhibits relatively poor correlation with three-dimensional imaging. Our study purpose was to use dual-energy X-ray absorptiometry (DXA) to indirectly assess the validity of the Craig's test. Twenty-three volunteers (n = 46; each hip analyzed separately) received two hip DXA scans using two different methods of positioning. During the first scan, a standard-sized wedge, the conventional tool of hip positioning for DXA scans, was used to fixate the legs without regard for individual levels of femoral version. For the second scan, the participants' hips were manually positioned according to their degree of femoral version determined by the Craig's test. We hypothesized that the bone mineral density (BMD) values from the customized positions would be lower due to the X-ray beams hitting the femoral neck perpendicularly. A paired t-test revealed weak evidence of a difference between BMD readings of the conventional and customized positions (p-value = 0.065); moreover, contrary to our hypothesis, the BMD readings obtained in the standard position were lower than those obtained in the customized position, albeit not significantly. Our findings suggest that the Craig's test is not a valid clinical assessment of true femoral version. A secondary conclusion is that the widespread use of the standard wedge for hip positioning during DXA scans is a better option than trying to find a customized position that is based on findings of the Craig's test.

Dynamic segmental kinematics of the lumbar spine during diagnostic movements.

Background: In vivo measurements of segmental-level kinematics are a promising avenue for better understanding the relationship between pain and its underlying, multi-factorial basis. To date, the bulk of the reported segmental-level motion has been restricted to single plane motions. Methods: The present work implemented a novel marker set used with an optical motion capture system to non-invasively measure dynamic, 3D in vivo segmental kinematics of the lower spine in a laboratory setting. Lumbar spinal kinematics were measured for 28 subjects during 17 diagnostic movements. Results: Overall regional range of motion data and lumbar angular velocity measurement were consistent with previously published studies. Key findings from the work included measurement of differences in ascending versus descending segmental velocities during functional movements and observations of motion coupling paradigms in the lumbar spinal segments. Conclusion: The work contributes to the task of establishing a baseline of segmental lumbar movement patterns in an asymptomatic cohort, which serves as a necessary pre-requisite for identifying pathological and symptomatic deviations from the baseline.

Dual-Sensing Piezoresponsive Foam for Dynamic and Static Loading.

Polymeric foams, embedded with nano-scale conductive particles, have previously been shown to display quasi-piezoelectric (QPE) properties; i.e., they produce a voltage in response to rapid deformation. This behavior has been utilized to sense impact and vibration in foam components, such as in sports padding and vibration-isolating pads. However, a detailed characterization of the sensing behavior has not been undertaken. Furthermore, the potential for sensing quasi-static deformation in the same material has not been explored. This paper provides new insights into these self-sensing foams by characterizing voltage response vs frequency of deformation. The correlation between temperature and voltage response is also quantified. Furthermore, a new sensing functionality is observed, in the form of a piezoresistive response to quasi-static deformation. The piezoresistive characteristics are quantified for both in-plane and through-thickness resistance configurations. The new functionality greatly enhances the potential applications for the foam, for example, as insoles that can characterize ground reaction force and pressure during dynamic and/or quasi-static circumstances, or as seat cushioning that can sense pressure and impact.

Classifying Nonspecific Low Back Pain for Better Clinical Outcomes: Current Challenges and Paths Forward.

SYNOPSIS: Low back pain classification systems are structured assessments used to guide choices of more specific treatments. Classification systems examined in randomized controlled trials have limited effects on pain intensity and disability compared to nonclassified interventions. Potential reasons for the lack of efficacy include (1) failing to assess multidimensional factors that contribute to pain, (2) relying on clinician judgement, (3) low accessibility, and (4) poor classification reliability. Overcoming these limitations is critical to deciding whether classification systems can improve clinical practice. Only once these limitations are addressed, can we feel certain about the efficacy, or lack thereof, of classification systems. This Viewpoint guides the reader through some limitations of common classification approaches and presents a path forward to open-access, reliable, and multidimensional precision medicine for managing low back pain. J Orthop Sports Phys Ther 2023;53(5):1-5. Epub: 5 April 2023. doi:10.2519/jospt.2023.11658.

Wearable Nanocomposite Sensor System for Motion Phenotyping Chronic Low Back Pain: A BACPAC Technology Research Site.

Chronic low back pain (cLBP) is a prevalent and multifactorial ailment. No single treatment has been shown to dramatically improve outcomes for all cLBP patients, and current techniques of linking a patient with their most effective treatment lack validation. It has long been recognized that spinal pathology alters motion. Therefore, one potential method to identify optimal treatments is to evaluate patient movement patterns (ie, motion-based phenotypes). Biomechanists, physical therapists, and surgeons each utilize a variety of tools and techniques to qualitatively assess movement as a critical element in their treatment paradigms. However, objectively characterizing and communicating this information is challenging due to the lack of economical, objective, and accurate clinical tools. In response to that need, we have developed a wearable array of nanocomposite stretch sensors that accurately capture the lumbar spinal kinematics, the SPINE Sense System. Data collected from this device are used to identify movement-based phenotypes and analyze correlations between spinal kinematics and patient-reported outcomes. The purpose of this paper is twofold: first, to describe the design and validity of the SPINE Sense System; and second, to describe the protocol and data analysis toward the application of this equipment to enhance understanding of the relationship between spinal movement patterns and patient metrics, which will facilitate the identification of optimal treatment paradigms for cLBP.

The influence of bed height as a percentage of participant height on low back forces when boosting a patient up in bed.

BACKGROUND: Repositioning patients is a frequent task for healthcare workers causing substantial stress to the low back. Patient handling methodologies that reduce low back load should be used. Some studies have observed the effect of bed height on back forces using a limited range of heights. This study details a wider range. OBJECTIVE: The aim of this study was to discover an optimal bed height for reducing low back force when boosting a patient. METHODS: 11 university students and local residents participated by completing a series of boosts with a 91.6 kg research assistant acting as dependent. The bed was adjusted 3% of participant height and 3 boosts were completed at each height which resulted in 8-10 different bed heights depending on the height of the participant. Motion and force data were collected to estimate low back forces via 3DSSPP. Pearson's R was performed to observe the correlation between caregiver height and low back forces. RESULTS: There were significant negative correlations between bed height and low back compression force at L4-L5 (r = -0.676, p = <0.001) and L5-S1 (r = -0.704, p = <0.001). There were no significant correlations with any shear forces. CONCLUSION: The highest bed height led to decreased low back compression forces regardless of participant height, but there was not a significant difference in shear forces. Thus, healthcare workers may experience less low back stress with the bed at a higher height. There may be a force tradeoff between the low back and other parts of the body that needs further exploration. Healthcare workers need to be made aware of the implications of adjusting the environment when performing patient handling tasks.

Assessing safety and treatment efficacy of running on intervertebral discs (ASTEROID) in adults with chronic low back pain: protocol for a randomised controlled trial.

Poor intervertebral disc (IVD) health is associated with low back pain (LBP). This 12-week parallel randomised controlled trial will evaluate the efficacy of a progressive interval running programme on IVD health and other clinical outcomes in adults with chronic LBP. Participants will be randomised to either a digitally delivered progressive interval running programme or waitlist control. Participants randomised to the running programme will receive three individually tailored 30 min community-based sessions per week over 12 weeks. The waitlist control will undergo no formal intervention. All participants will be assessed at baseline, 6 and 12 weeks. Primary outcomes are IVD health (lumbar IVD T2 via MRI), average LBP intensity over the prior week (100-point visual analogue scale) and disability (Oswestry Disability Index). Secondary outcomes include a range of clinical measures. All outcomes will be analysed using linear mixed models. This study has received ethical approval from the Deakin University Human Research Ethics Committee (ID: 2022-162). All participants will provide informed written consent before participation. Regardless of the results, the findings of this study will be disseminated, and anonymised data will be shared via an online repository. This will be the first study to evaluate whether a progressive interval running programme can improve IVD health in adults with chronic LBP. Identifying conservative options to improve IVD health in this susceptible population group has the potential to markedly reduce the burden of disease. This study was registered via the Australian New Zealand Clinical Trials Registry on 29 September 2022 (ACTRN12622001276741).

The Back Pain Consortium (BACPAC) Research Program: Structure, Research Priorities, and Methods.

In 2019, the National Health Interview survey found that nearly 59% of adults reported pain some, most, or every day in the past 3 months, with 39% reporting back pain, making back pain the most prevalent source of pain, and a significant issue among adults. Often, identifying a direct, treatable cause for back pain is challenging, especially as it is often attributed to complex, multifaceted issues involving biological, psychological, and social components. Due to the difficulty in treating the true cause of chronic low back pain (cLBP), an over-reliance on opioid pain medications among cLBP patients has developed, which is associated with increased prevalence of opioid use disorder and increased risk of death. To combat the rise of opioid-related deaths, the National Institutes of Health (NIH) initiated the Helping to End Addiction Long-TermSM (HEAL) initiative, whose goal is to address the causes and treatment of opioid use disorder while also seeking to better understand, diagnose, and treat chronic pain. The NIH Back Pain Consortium (BACPAC) Research Program, a network of 14 funded entities, was launched as a part of the HEAL initiative to help address limitations surrounding the diagnosis and treatment of cLBP. This paper provides an overview of the BACPAC research program's goals and overall structure, and describes the harmonization efforts across the consortium, define its research agenda, and develop a collaborative project which utilizes the strengths of the network. The purpose of this paper is to serve as a blueprint for other consortia tasked with the advancement of pain related science.

Lateral abdominal muscles of adults with hypermobility may be partially impaired during contraction.

Background: Muscle function may be impaired in people with generalised hypermobility, yet prior studies have primarily focused on muscles within the extremities. We aimed to examine changes in lateral abdominal muscle (transversus abdominis (TrA) and the external (EO) and internal abdominal obliques (IO)) thickness and length during contraction between participants with and without hypermobility. Methods: This cross-sectional study examined 12 participants with hypermobility and 12 age-matched, sex-matched, height-matched and weight-matched participants without hypermobility. The Beighton and Belavy-Owen-Mitchell score assessed systemic hypermobility. Muscle thickness and length were measured via panoramic ultrasound scans at rest and during contraction. Results: When compared with rest across all lumbar levels (L1-L5), contraction produced a lesser increase in TrA thickness (ß=0.03, p=0.034) for participants with hypermobility compared with control. No group-by-condition interaction was observed for TrA length across all lumbar levels (L1-L5; p=0.269). Contraction produced a greater decrease in EO thickness (ß=0.08, p=0.002) at L3 only for participants with hypermobility compared with control. No group-by-condition interactions were observed for IO thickness. Conclusion: Participants with hypermobility had partially impaired lateral abdominal muscle function given a lesser ability to increase TrA muscle thickness during contraction compared with controls.

Generation of GLA-knockout human embryonic stem cell lines to model peripheral neuropathy in Fabry disease.

Fabry disease is an X-linked glycolipid storage disorder caused by mutations in the GLA gene which result in a deficiency in the lysosomal enzyme alpha galactosidase A (AGA). As a result, the glycolipid substrate Gb3 accumulates in critical tissues and organs producing a progressive debilitating disease. In Fabry disease up to 80% of patients experience life-long neuropathic pain that is difficult to treat and greatly affects their quality of life. The molecular mechanisms by which deficiency of AGA leads to neuropathic pain are not well understood, due in part to a lack of in vitro models that can be used to study the underlying pathology at the cellular level. Using CRISPR-Cas9 gene editing, we generated two clones with mutations in the GLA gene from a human embryonic stem cell line. Our clonal cell lines maintained normal stem cell morphology and markers for pluripotency, and showed the phenotypic characteristics of Fabry disease including absent AGA activity and intracellular accumulation of Gb3. Mutations in the predicted locations in exon 1 of the GLA gene were confirmed. Using established techniques for dual-SMAD inhibition/WNT activation, we were able to show that our AGA-deficient clones, as well as wild-type controls, could be differentiated to peripheral-type sensory neurons that express pain receptors. This genetically and physiologically relevant human model system offers a new and promising tool for investigating the cellular mechanisms of peripheral neuropathy in Fabry disease and may assist in the development of new therapeutic strategies to help lessen the burden of this disease.

Brain Structure in Acutely Underweight and Partially Weight-Restored Individuals With Anorexia Nervosa: A Coordinated Analysis by the ENIGMA Eating Disorders Working Group.

BACKGROUND: The pattern of structural brain abnormalities in anorexia nervosa (AN) is still not well understood. While several studies report substantial deficits in gray matter volume and cortical thickness in acutely underweight patients, others find no differences, or even increases in patients compared with healthy control subjects. Recent weight regain before scanning may explain some of this heterogeneity. To clarify the extent, magnitude, and dependencies of gray matter changes in AN, we conducted a prospective, coordinated meta-analysis of multicenter neuroimaging data. METHODS: We analyzed T1-weighted structural magnetic resonance imaging scans assessed with standardized methods from 685 female patients with AN and 963 female healthy control subjects across 22 sites worldwide. In addition to a case-control comparison, we conducted a 3-group analysis comparing healthy control subjects with acutely underweight AN patients (n = 466) and partially weight-restored patients in treatment (n = 251). RESULTS: In AN, reductions in cortical thickness, subcortical volumes, and, to a lesser extent, cortical surface area were sizable (Cohen's d up to 0.95), widespread, and colocalized with hub regions. Highlighting the effects of undernutrition, these deficits were associated with lower body mass index in the AN sample and were less pronounced in partially weight-restored patients. CONCLUSIONS: The effect sizes observed for cortical thickness deficits in acute AN are the largest of any psychiatric disorder investigated in the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) Consortium to date. These results confirm the importance of considering weight loss and renutrition in biomedical research on AN and underscore the importance of treatment engagement to prevent potentially long-lasting structural brain changes in this population.

Generation of an in vitro model for peripheral neuropathy in Fabry disease using CRISPR-Cas9 in the nociceptive dorsal root ganglion cell line 50B11.

Fabry disease is a glycosphingolipid storage disorder that is caused by a genetic deficiency of the lysosomal enzyme alpha-galactosidase A (AGA, EC 3.2.1.22). As a result, the glycolipid substrate, globotriaosylceramide (Gb3) accumulates in various cell types throughout the body producing a multisystem disease that affects the vascular, cardiac, renal, and nervous systems. A hallmark of this disorder is neuropathic pain that occurs in up to 80% of Fabry patients and has been characterized as a small fiber neuropathy. The molecular mechanism by which changes in AGA activity produce neuropathic pain is not clear, in part due to a lack of relevant model systems. Using 50B11 cells, an immortalized dorsal root ganglion neuron with nociceptive characteristics derived from rat, we used CRISPR-Cas9 gene editing of the galactosidase alpha (GLA) gene for AGA to create two stable knock-out clones that have the phenotypic characteristics of Fabry cells. The cell lines show severely reduced lysosomal AGA activity in homogenates as well as impaired degradation of Gb3 in cultured cells. This phenotype is stable over long-term culture. Similar to the unedited 50B11 cell line, the clones differentiate in response to forskolin and extend neurites. Flow cytometry experiments demonstrate that the gene-edited cells express TRPV1 pain receptor at increased levels compared to control, suggesting a possible mechanism for increased pain sensitization in Fabry patients. Our 50B11 cell lines show phenotypic characteristics of Fabry disease and grow well under standard cell culture conditions. These cell lines can provide a convenient model system to help elucidate the molecular mechanism of pain in Fabry patients.

Accounting for Viscoelasticity When Interpreting Nano-Composite High-Deflection Strain Gauges.

High-deflection strain gauges show potential as economical and user-friendly sensors for capturing large deformations. The interpretation of these sensors is much more complex than that of conventional strain gauges due to the viscoelastic nature of strain gauges. This research endeavor developed and tested a model for interpreting sensor outputs that includes the time-dependent nature of strain gauges. A model that captures the effect of quasi-static strains was determined by using a conventional approach of fitting an equation to observed data. The dynamic relationship between the strain and the resistance was incorporated by superimposing dynamic components onto the quasi-static model to account for spikes in resistances that accompany each change in sensor strain and subsequent exponential decays. It was shown that the model can be calibrated for a given sensor by taking two data points at known strains. The resulting sensor-specific model was able to interpret strain-gauge electrical signals during a cyclical load to predict strain with an average mean absolute error (MAE) of 1.4% strain, and to determine the strain rate with an average MAE of 0.036 mm/s. The resulting model and tuning procedure may be used in a wide range of applications, such as biomechanical monitoring and analysis.

Grey wolf genomic history reveals a dual ancestry of dogs.

The grey wolf (Canis lupus) was the first species to give rise to a domestic population, and they remained widespread throughout the last Ice Age when many other large mammal species went extinct. Little is known, however, about the history and possible extinction of past wolf populations or when and where the wolf progenitors of the present-day dog lineage (Canis familiaris) lived1-8. Here we analysed 72 ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. We found that wolf populations were highly connected throughout the Late Pleistocene, with levels of differentiation an order of magnitude lower than they are today. This population connectivity allowed us to detect natural selection across the time series, including rapid fixation of mutations in the gene IFT88 40,000-30,000 years ago. We show that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east. However, we also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, reflecting either an independent domestication process or admixture from local wolves. None of the analysed ancient wolf genomes is a direct match for either of these dog ancestries, meaning that the exact progenitor populations remain to be located.

Accurate Prediction of Knee Angles during Open-Chain Rehabilitation Exercises Using a Wearable Array of Nanocomposite Stretch Sensors.

In this work, a knee sleeve is presented for application in physical therapy applications relating to knee rehabilitation. The device is instrumented with sixteen piezoresistive sensors to measure knee angles during exercise, and can support at-home rehabilitation methods. The development of the device is presented. Testing was performed on eighteen subjects, and knee angles were predicted using a machine learning regressor. Subject-specific and device-specific models are analyzed and presented. Subject-specific models average root mean square errors of 7.6 and 1.8 degrees for flexion/extension and internal/external rotation, respectively. Device-specific models average root mean square errors of 12.6 and 3.5 degrees for flexion/extension and internal/external rotation, respectively. The device presented in this work proved to be a repeatable, reusable, low-cost device that can adequately model the knee's flexion/extension and internal/external rotation angles for rehabilitation purposes.

Ultrasound imaging measures of vertebral bony landmark distances are weakly to moderately correlated with intervertebral disc height as assessed by MRI.

Objectives: To assess the validity and reliability of ultrasound-derived interbony landmark distances as a proxy for MRI-derived intervertebral disc (IVD) height. Methods: This is a cross-sectional criterion validity study. Twelve college-aged participants without current low back pain completed both MRI and ultrasound imaging of the lumbar spine in a prone position. Single-segment and multisegment distances between the spinous and mammillary processes at the lumbar segments (L2/L3, L3/L4, L4/L5) were measured twice using ultrasound and analysed digitally. Sagittal slices of the lumbar spine were taken via T1-weighted MRI and IVD height, and the overall distance between IVDs L2/L3 and L4/L5 was imaged once and measured twice. Results: There was moderate correlation between multilevel-based measurements (overall distance between L2 and L5, r=0.677, p=0.016) and the average across three levels (r=0.596, p=0.041) when using the spinous processes as bony landmarks. Single-segment measures were not significantly correlated (all: p>0.092). Accuracy and precision were better for the overall MRI-derived distance between the three IVDs from L2 and L5 MRI and the distance measured between the spinous processes L2-L5. There was excellent reliability within multiple measurements at each location, with intraclass correlation coefficient, ICC(3,1), ranging from 0.93 to 0.99 (95% CI 0.82 to 0.99) for ultrasound and from 0.98 to 0.99 (95% CI 0.92 to 0.99) for MRI. Conclusion: Findings do not support the use of ultrasound imaging for estimating single-segment IVD height, yet it may be used to measure the change in distance over time with a certain degree of precision based on its excellent reliability.

Internal and External Oblique Muscle Asymmetry in Sprint Hurdlers and Sprinters: A Cross-Sectional Study.

The abdominal muscles are vital in providing core stability for functional movements during most activities. There is a correlation between side asymmetry of these muscles and dysfunction. Thus, the purpose of this study was to evaluate and compare trunk muscle morphology and trunk rotational strength between sprint hurdlers, an asymmetrical sport, and sprinters, a symmetrical sport. Twenty-one trained collegiate sprint hurdlers and sprinters were recruited for the study (Hurdlers: 4M, 7F; Sprinters: 8M, 2F), average age (years) hurdlers: 20 ± 1.2; sprinters: 20.4 ± 1.9, height (cm) hurdlers: 172.6 ± 10.2; sprinters: 181.7 ± 4.5, and weight (kg) hurdlers: 67.6 ± 12.0; sprinters: 73.9 ± 5.6. Using real-time ultrasound, panoramic images of the internal oblique (IO) and external oblique (EO) were obtained at rest and contracted (flexion and rotation) in a seated position for both right and left sides of the trunk. While wearing a specially crafted shoulder harness, participants performed three maximal voluntary trunk rotational contractions (MVC). The three attempts were then averaged to obtain an overall MVC score for trunk rotation strength. Average MVC trunk rotational strength to the right was greater among all participants, p < 0.001. The IO showed greater and significant thickness changes from resting to contracted state than the EO, this was observed in all participants. The IO side asymmetry was significantly different between groups p < 0.01. Hurdlers, involved in a unilaterally demanding sport, exhibited the expected asymmetry in muscle morphology and in trunk rotational strength. Interestingly, sprinters, although involved in a seemingly symmetrical sport, also exhibited asymmetrical trunk morphology and trunk rotational strength.

Quality of knee strengthening exercises performed at home deteriorates after one week.

BACKGROUND: To compare the performance (as determined by lower extremity kinematics) of knee exercises in healthy middle-aged and older individuals immediately after instruction and one week later. METHODS: This is a cross-sectional study in a laboratory setting. Nineteen healthy volunteers (age [y] 63.1 ± 8.6, mass [kg] 76.3 ± 14.7, height [m] 1.7 ± 0.1) participated in this study. High speed video and reflective markers were used to track motion during four exercises. The exercises were knee flexion, straight leg raise, and "V "in supine position, and hip abduction in side lying position. All participants received verbal and tactile cues during the training phase and the therapist observed and, if necessary, corrected the exercises. Upon return a week later the participants performed the same exercises without any further instructions. Knee and hip sagittal and rotational angles were extracted from the motion capture. A repeated measures t-test was used to compare the motions between two visits. RESULTS: Participants demonstrated more knee flexion during straight leg raise and "V in" exercises at the 2nd visit compared to the 1st visit (both p <  0.05). During the "V out" exercise, they performed more external rotation (p <  0.05) while they showed more internal rotation during the "V in" exercise at the 2nd visit compared to the 1st visit. CONCLUSIONS: Exercise performance declined significantly in healthy middle-aged and older individuals one week after instruction. This decline occurred despite an instructional exercise sheet being given to every participant. Other approaches designed to help individuals retain the ability to perform rehabilitative exercises correctly need to be explored.